I'm very pleased to present issue No. 2 for 1997. Along with letters to the editor, news from ESA Council, PAB, NSW Branch, and the National Conference, you'll also find an array of professional development resources. Of particular interest is an article by Kim Vicente (University of Toronto) titled "Is it always a good idea to design an interface to match the operator's mental model?" followed by commentary on the article by ESA members Bill Green and Gitte Lingaard. Additional comments on this topic are welcome.
Two articles are available in full in the electronic version (http://www.uq.edu.au/eaol/) of the journal only. The first is "A checklist for handle design" by Michael Patkin. This article was included in the Proceedings of the 1985 Victorian Occupational Health & Safety Convention, but has been republished in Ergonomics Australia On-Line (EAOL) to make it more accessible. The second item included in EAOL is "A walk through a laboratory" by myself and Elizabeth Bunker. The latter provides pictorial examples from a walk through of a laboratory to illustrate principles of workplace design and will primarily be of interest to student members, or those who teach students. Permission is given to use these materials for non-profit purposes provided the source is acknowledged. The article is one of a series of case studies prepared with support from the Australia Occupational Health & Safety Trust. (The trust is calling for funding applications for 1998. The closing date is September 30, further details are provided elsewhere in this issue)
In my role as ex-PAB member I'm very pleased to see the first iteration of PAB recertification procedures finalised and published. In my new role as editor of Ergonomics Australia I'm also pleased to see the inclusion of non-refereed publications and review articles as ways of meeting recertification requirements. I hope that this provides the incentive needed to prompt more Certified Professional Ergonomists to provide such contributions for publication in Ergonomics Australia. and I look forward to the deluge!
Best wishes to all,
Robin Burgess-Limerick
Email: robin@hms.uq.edu.au
From Michael Patkin (xpymp@whx.whyalla.unisa.edu.au)
EAOL is ABSOLUTELY BRILLIANT!
For some months I have been saying to friends that I knew that the millenium [the good one] had arrived because I had seen 3.5 inch diskettes at the supermarket two aisles down from the breakfast cereals.
As president of ESA, at the 1985 or so Council meeting I battled for a bulletin board system for the Society, but it all seemed to difficult and too far away. Suddenly it is here in living breathing technicolour - and electronically manipulable for search, downloading, easy retrieval, and implicit safe storage. And your layout is just great!
Not perfect, of course, though damn near. I had to copy and past your email address to the Mail program, instead of just clicking onto your email address - just to show I'm not just full of unctuous flattery but indeed sitting up and taking note. You are of course welcome to reproduce this fanmail.
Ergonomically I can't think of a better time to be alive - such tools as these now here and usable. And the layout is great. The big challenges are going to be, inevitably, the organisation of information, its findability and usability. I think the tools to use will be site-specific search engines such as AltaVista, where I had previously pinned all my hopes on ISYS, which I think may still turn out to be the winner because it is so smart.
If I haven't outlasted my welcome, here is a query. Where can I get an electronic versionof MIL-STD-1472c on the Web, without have to negotiate a huge trapdoor needing money to traverse?
[Editor's note: The answer to Michael's query re MIL-STD-1472C is that the current version is 1472D, and that it is not available electronically for love or money, at least as far as I could determine (although it can be ordered online!)]
Brief summary of the March 17 ESA Council teleconference
1. Model for Branch Scientific Program Coordinators:
The Victorian Branch in collaboration with PAB and Jim Carmichael (as co-ordinator of the competencies project) agreed to take responsibility formn drafting a model of scientific programming that would assist Branches.
2 SIGs as structural building block (of the Society):
At its September meeting Council resolved that a review of the future, direction, purposes and funding of SIGs within the Society's structure be considered through a Workshop at the next face-to-face (May 1997) Council meeting.
3 Media Kit:
The ACT Branch reported that it had drafted a marketing plan which was ready for distribution to Councillors with these Minutes in order that the Council could seek Branch input and consider at the next meeting.
4 PAB re-Certification:
The final draft of the re-certification document was tabled, amended and approved.
5 ESA Membership card:
It was reported that in accordance with the decision of the last Council meeting, a Membership Card is being produced and will be issued on receipt of renewal subscriptions for the 1997-98 year.
6 President of IEA:
Council formally ratified Australia's nomination of Margaret Bullock as a candidate for the position of President of the International Ergonomics Association.
7 Professional Enquiries & Complaints:
It was resolved to ask the PAB to consider and to recommend terms, costs, structure and process for the establishment of an Appeal Panel to which members of the public and the Society may refer, and to recommend a set of By-Laws to Council, so that the appeal mechanism is consistent with the existing Code of Practice and the Constitution.
8 Electronic Communication:
Councillors noted that -
* ESA has a very general Home Page (it needs updating but that is in hand)
* The ESA Office has an email address - esa@ozemail.com.au - which is beginning to work well
* several members are on email and their site addresses are part of the Directory information
* The Editor of Ergonomics Australia is proposing that there be an on-line version of EA
* South Australia is proposing to create its own home-page to advertise scientific meetings
It was agreed that the Membership's views be sought on how the Society would like to use the electronic media.
Accordingly, members are invited to contact, before 1 June 1997, their Branch Councillor or the Secretariat with ideas/opinions/concerns about this topic so that the views of members can be considered by the Council.
Ian Mitchell
This is the first report of the new Board formed following the elections held earlier this year. There are still some vacancies on the board which at present consists of Elizabeth Bunker (Queensland) Jeffrey Frith (ACT), Marcia Lusted (NSW, elected secretary) and Neil Adams (NSW, elected chair). The new Board expects to build on thework of the previous Board which made considerable progress on several vital issues:
(1). Nomenclature:
Professionally certificated ergonomists and the Federal Council have reached agreement about the nomenclature and the post-nominals that will apply. The term to be used is"Certified Professional Ergonomist (CPE)". The post nominal to be used consists of those three letters: CPE.
(2). Brochures:
Two brochures have finally reached completion and should be circulated at the same time as the next issue of "Ergonomics Australia". The first is a general informational brochure for circulation within the society, intended to increase members'awareness of the value of professional certification - to individual members and to the society as a whole. The second is for use by CPEs (Certified Professional Ergonomists) in promoting their own ergonomic services to prospective clients.
(3). Certification maintenance (Re-certification).
The Board has finalised the criteria and requirements for certification maintenance. The various activities which contribute to a total number of points to be accumulated over a three year period have been defined, the points allocated and the procedure ratified by Federal Council. The Board is fully aware of the fact that the re-certification criteria and procedures may (probably will) need to be reviewed when the competency standards are finalised. There was some concern expressed about the criteria for recertification in that a superficial scanning of the list of criteria might lead one to feel that thoseworking in academia would find it easier to produce performances that would qualify them than would those working as consultants or employed in industry or public service.However, a thoughtful review of the items which may qualify a person for recertification has satisfied the Board and the Federal Council that any ergonomist who is performing effectively in the profession would be productive in many of the areas ofactivity and certainly in a sufficient number of the areas to accumulate the required 60 points over a period of three years.
The recertification process:
There are three parts of the recertification process:
(a). The self-administered assessment: CPEs are required to maintain personal records of their level of professional development and activity on an annual basis;
(b). The declaration by the CPE of their continuing development as an ergonomist. The CPE is asked to submit copies of records which justify the declaration.
(c). Confirmation by the Board of the CPE's standing (or a request for additional validation). Members of the Board itself, seeking recertification, must submit their declaration to three other CPEs nominated independantly by Federal Council from the register of CPEs.
(4). Criteria and activities for recertification:
The following activities with their respective point allocation may be recognised as contributing to one's professional development and eligibility for recertification. It must be noted that it is expected that the CPE will accumulate 20 points a year with no more than half of the 20 points each year being derived from any one of the professional activities specified below:
Authorship of refereed published articles and/or books or the editorship of an anthology (10 points per publication).
Preparation and presentation of papers or workshops to ESA, other professional/industry bodies and educational institutions (5 points per presentation).
Non-refereed publications (5 points each)
Chairing of international conference sessions (5.).
Preparation and conduct of structured courses or training programmes (5
points).
Preparing a critical study of ergonomics literature including: ergonomics; applied ergonomics; research papers and other relevant material (5 points each document).
Documented structured research of specific relevance to the science, teaching or practice of ergonomics (3 points each)
Structured study in the area of personal or business skills designed to increase management/business efficiency (2 points for each half day of study).
Attendance at formal courses including conferences, workshops, seminars, lectures and scientific meetings. Only programmes presented by universities, the ESA, the ESA special interest groups, professional/industry bodies and other relevant course providers may be cited as professional development (1 point per half day of attendance).
Membership of committees, organised either by the ESA or other professional, educational or industry bodies concerned with the advancement of ergonomics (1 point per meeting date).
Membership of and regular attendance at formally constituted ESA administrative or special interest group activities (1 point for each half day of activity)
Participation at special functions such as Ergo Week, awards nights, lunches with keynote speakers and the like (1 point for each half day of activity).
Other client oriented activities or reports, provided that they are accompanied by Quality Assurance information or feedback from the client (points according to the extent of the report or intervention, ranging from 1 to a maximum of 10, allocated and justified by the CPE himself/herself).
(5). Management of the Board:
It was agreed that the board should retain a formal secretary as well as a chair, although most of the routine activities would be undertaken by the Federal secretariat. Financial matters would be handled entirely by the secretariat. It was considered to be highly desirable that the Board should consist of six elected CPEs, preferably but not necessarily providing for informal Branch representation on the Board.There are still strong hopes that representation from WA and from Victoria will be forthcoming. (South Australia is in a rather difficult position with the few available members being so heavily involved in Federal Council affairs - a laudable situation since one would hope and expect to see CPEs playing a significant role in the society - but obviously limiting their capacity to be directly involved in PAB management as well).
(6). Continuing activities:
The number of CPEs is growing steadily. We like to think that this growth reflects a growth in awareness of the value of Professional Certification to individual ergonomists and it is also a recognition by the Society of the status of those members who achieve this level of membership. Perhaps more importantly, it is a message to the world of clients and employers that that member has been recognised by the professional Society as having the competence and professional standing that justify that grade of membership. The new Board is currently developing its two year plan forthe PAB andwelcomes suggestions and advice from CPEs and from the membership at large. The next meeting of the Board - a teleconference - is to be held on 6 May at 1530 E S T.
(7). Last word:
As the incoming chair, I would like to express my appreciation of Jeffrey Frith's consistent efforts during the last couple of years, and the able support of the retiring members of the Board. I would also thank Jeffrey for his decision to offer himself again for election and thus to remain on the Board for another two years. I welcome the two new members to the Board - Marcia and Elizabeth, and look forward to working productively with them to further the professionalism and effectiveness of the PAB and the ESA as a whole. I also look forward to a continuing growth in both numbers and value (value to the Society as a whole, to ergonomics in Australia, and to the individual CPEs) of the Professional Affairs Board.
With best wishes for your continued growth in ergonomics,
Yours faithfully,
Neil Adams.
(Dr. Neil Adams & Associates, P.O. Box 10, Broadway, NSW 2007;
Ph: 02 92121824; Fax: 02 92123069; e-mail: doctergo@OzEmail.com.au
NSW
Christine Aickin (Chairperson) Phone/Fax: (02) 9810 2199
Trudy Tilbury (Secretary) Phone: 0419 447 440 Fax: (02) 9759 5577
VIC
Michael Michaliades (Chairperson) Phone: (03) 9319 5870 Fax: (03) 9319 5909
Phil Clark (Secretary) Phone: (03) 9844 3091
QLD
Justin O'Sullivan (Chairperson) (07) 3895 8111 Fax: (07) 3895 8222
Melanie McGaw (Secretary) Phone: (07) 3896 1567 Fax: (07) 3247 9426
SA
Lyn Barnett (Chairperson) Phone: (08) 8226 6553 Fax: (08) 8232 0334
Marion Pocock (Secretary) Phone: (08) 8263 5158 Fax: (08) 8263 7518
WA
Annabel Cooper (Chairperson) Phone: (09) 322 7622 Fax: (09) 322 7624
Judy McCarthy (Secretary) Phone: (09) 381 9800 Fax: (09) 381 3299
ACT
Margaret Head (Chairperson) Phone: (06) 244 2169 Fax: (06) 285 3492
Lenore Gunning (Secretary) Phone: (06) 202 8834 Fax: (06) 202 8855
COUNCIL
Dr Ian Gibson (President) Phone/Fax: (09) 279 8783
Jenni Miller (General Secretary) Phone: (09) 386 1419 Fax:: (09) 386 3946
Rod Powell (Treasurer) Phone: (09) 327 8815 Fax: (09) 322 7651
Verna Blewett (Past President) Phone: (08) 8361 2501 Fax: (08) 8361 2504
Trudy Tilbury (Councillor) Phone: 0419 447 440 Fax: (02) 9759 5577
Michael Michaliades (Councillor) Phone: (03) 9319 5870 Fax: (03) 9319 5909
Jim Carmichael (Councillor) Phone: (07) 3233 1304 Fax: (07) 3233 1390
Phillip Moody (Councillor) Phone: (08) 8282 8867 Fax: (08) 8282 8780
Angela Summers (Councillor) Phone: (09) 224 3430 Fax: (09) 224 1137
Margaret Head (Councillor) Phone: (06) 244 2169 Fax: (06) 285 3492
The year got off to a good start with the Competency Workshop in February which helped to clarify the personal and corporate thinking (of those members who attended!) about the hard realities as opposed to feel-good wishes in setting out the goals and criteria for our activities as ergonomists. This was followed in March by a presentation on current trends in shiftwork research and practice compared to the traditional patterns which have been in operation for many years. A brief overview of this presentation follows:
Shiftwork
by Ann Williamson and Rebecca Mitchell
Shiftwork has been a topic of research for decades and it has been established that many shiftworkers suffer ill effects from working the irregular hours that shiftwork requires. Ill effects arising from disruption to biological rhythms, social and domestic restrictions and individual concerns. However, there are some individuals for which working irregular hours poses no problems at all.
Solutions are being sought to combat the adverse effect that shiftwork has on many individuals. One alternative to the traditional shiftwork pattern is the adoption of compressed work weeks. Compressed work weeks involve the use of a set block of shifts of increased length, usually of 12 hours duration, compensated for by shortening the work week with three to four extra days rest.
It is generally accepted that compressed work weeks can be advantageous to the individual as they contain shorter blocks of shifts, fewer successive night shifts, increased blocks of free time and more weekends off.
Conversely, these 12 hour shifts involve an additional four hours in working time per shift, with this increase in working time possibly leading to fatigue. The extended work hours may also unfavourably affect a worker's health and the recovery time for an individual after completing a block of 12 hour shifts may often be extended, with individuals generally more fatigued after completing the extended shift hours.
When implementing compressed work weeks several factors should be considered:
(1) the nature of the work to be performed. For instance, individuals who work with noxious chemicals, where exposure standards for the extended workdays may not be developed, should not contemplate working compressed work weeks, nor should individuals who are involved in heavy physical labour;
(2) the type of workload involved. Extending the work hours in a job that requires an individual to maintain high levels of attention, where the consequences of an error or non- reaction may be dire for the individual or for the community at large, is not recommended. However, some occupations may have flexible workloads and in this instance it is recommended that tasks that require error- free performance should not be scheduled towards the end of a 12 hour shift;
(3) the number of consecutive 12 hour shifts should not exceed four, with no more than two consecutive 12 hour night shifts;
(4) overtime should not be required of individuals working 12 hour shifts;
(5) suitable arrangements need to be made to cover individuals who are absent from work through sickness;
(6) it is essential that the shiftworkers are consulted and take an active role in determining the changes to be made to the current shift roster and how these changes are to be implemented in the workplace; and
(7) an evaluation of the new shift roster should be undertaken to establish the benefits, or any adverse effects that the new roster has for the shiftworkers. After the evaluation is completed, alterations to the new shift roster, or changes to the way work is completed may need to be conducted.
It is true that in some industries the adoption of the compressed work week has benefited shiftworkers through increasing their recreation time, improving their quality and duration of sleep and through improving their physical health and well- being. However, each workplace and each workforce is unique and different shift rosters will suit different workplaces. Compressed work weeks may not be suitable for all workers as an alternative to traditional shiftwork.
Program for NSW Scientific Meetings in 1997
April 23 - Ergonomics Research, Design Practice - Bridging the Gap
Stephen Ward & Jonathan Talbot
May 21 - Ergonomics Reporting & Communication
Pamela Freeman
June 18 - Vibration & Environmental Measurement in Ergonomics
Byron Longstaff & Bruel & Kjaer
July 23 - Cognitive Ergonomics & Warnings
Austin Adams
August 20- Work Physiology & Project Aquarius
John Brotherhood
September 17- Designing for Useability
Roger Hall & Jonathan Talbot
October 22 - Slipping & Falling - the Measurement Debate & Forensic Issues
Neil Adams & Mike Stevenson
In addition, there will be a One Day Workshop on Friday, 27 June 1997:
Effective Communication & Report Writing in Ergonomics
Pamela Freeman
and
Wednesday 19 November 1997 - NSW Branch ANNUAL GENERAL MEETING
Unless otherwise notified, all scientific meetings are conducted at the "Worksafe" Auditorium, 92-94 Parramatta Road, Camperdown (opposite Sydney Uni near Missenden Road, at 6.00 pm for 6.30 pm. All members and their friends/colleagues are welcome - visitors are potential members! Ergonomes visiting from other states are particularly welcome to join us - make yourself known to the welcoming committee and join us for dinner afterwards at a nearby restaurant (costs always competitively small!).
Backwatch Program
Over the past year the NSW Branch has actively promoted the various Backwatch initiatives via our state newsletter. Max Hely, a member of our Branch committee and a WorkCover employee has contributed a short article to alert a wider readership via "Ergonomics Australia" - "Participatory Ergonomics at Industry Level" which appears later in this issue.
Shann Gibbs
NSW Correspondent "EA"
PRODUCTIVITY, ERGONOMICS & SAFETY - THE TOTAL PACKAGE
Gold Coast, Queensland, 24-27 November 1997
LATE NEWS - the conference has been endorsed by IEA (level 3).
'Call for Papers' brochures were sent out last month. Closing date for submission of abstracts is 1 June l997. (So it is time to get your abstract together).
ESA members are invited to consider contacting a group of authors to present three or four papers on related topics as a symposium.
The convenor of PsychSig, Dr. Janice Langan-Fox of the Department of Psychology, University of Melbourne, would be pleased to receive ideas and offers of participation to arrange symposia from psychologists and other interested persons for the ESA National Conference. Contact Dr. Langan-Fox, ph. 03 9344 6290; fx 03 9347 6618; email J.Langan-Fox@Psych.unimelb.edu.au
Keynote speakers
The scientific committee has approached two international keynote speakers.
One keynote speaker confirmed for the conference is Prof. Stuart McGill, Waterloo University, Canada. A dynamic speaker, Prof. McGill gave an outstanding lecture to a "standing room only" audience at 1996 Australian Sports Medicine Conference in Hobart. To whet your appetite, the information below describe Prof. McGill's research interests.
"My research spans from basic investigations into normal low back function to applied studies of injury mechanisms and evaluating ways to avoid injury. We have two separate laboratory approaches - one which examines intact humans which utilizes a rather unique approach that monitors spine motion and body segment position, muscle activation, ligament involvement and modelling tissue loading in each individual subject; and a second approach where we examine the mechanical behaviour of low back tissues and spine specimens harvested mostly from pigs. Some of my graduate students have been involved in investigating the load tolerance of the spine under various types of load, assessment of spine stability, examination of devices such as abdominal belts and examination of various injury mechanisms."
Selected recent publications
Rafacz,W. and McGill, S.M. (1996) Abdominal belts increase diastolic blood pressure,J.Occup.Env.Med. 38(9): 925-927.
McGill, S.M. (1996). Invited Manuscript: Distribution of tissue loads in the low back during a variety of rehabilitation tasks. J. Rehab. Res. Develop.
McGill, S.M., van Wijk, M., Axler, C.T., Gletsu, M. (1996). Spinal shrinkage: Is it useful for evaluation of low back loads in the workplace. Ergonomics, 39(1): 92- 102.
Cholewicki, J., and McGill, S.M. (1996). Mechanical stability of the in vivo lumbar spine: Implications for injury and chronic low back pain. Clin. Biomech. 11(1):1- 15.
McGill, S.M. (1996). A revised anatomical model of the abdominal musculature for torso flexion efforts. J. Biomech. 29(7): 973-977.
McGill, S.M., Juker, D., Kropf., P. (1996). Quantitative intramuscular myoelectric activity of quadratus lumborum during a wide variety of tasks, Clin. Biomech, 11(3): 170-172.
McGill, S.M., Norman, R.W., Cholewicki, J. (1996). A simple polynomial for predicting low back compression in 3-D industrial tasks, Ergonomics 39(9): 1107-1118.
Potvin, J.R., Norman, R.W., McGill, S.M. (1996). Mechanically corrected EMG for the continuous estimation of erector spine muscle loading during repetitive lifting. Eur. J. Appl. Physiol.74: 119-132.
Cholewicki, J., and McGill, S.M., Norman, R.W. (1995). Comparison of muscle forces and joint load from an optimization and EMG assisted lumbar spine model: Towards development of a hybrid approach. J. Biomech. 28(3): 321-331.
McGill, S.M., Seguin, J., Bennett, G., (1994). Passive stiffness of the lumbar torso about the flexion-extension, lateral bend and axial twist axes: The effect of belt wearing and breath holding. Spine. 19(6):696-704.
Sponsorship & Trade display
Sponsors and participants in the trade displays are also sought. An Exhibition and Sponsorship Package is available from the Conference Secretariat.
Further Information
For further information and general enquiries please contact:
Conference Secretariat
PO Box 177, RED HILL QLD 4059 AUSTRALIA
tel: 07 3368 2644 (international callers: + 61 7 3368 2644)
Freecall: 1 800 811 510 (Australian callers from outside Brisbane only)
Facsimile: 07 3369 3731 (international callers: + 61 7 3369 3731)
e-mail: carillon@ozemail.com.au
Congratulations to Margaret Bullock
Congratulations to Prof. Margaret Bullock are in order (again!). Margaret was made Member in the General Division of the Order of Australia (AM) in this years Australia Day honours for her service to physiotherapy as research leader, academic and administrator.. Margaret is a past president of the ESA (1988-90), and recent recipient of the ESA Presidents Medal (1995). Margaret is Head of the School of Health and Rehabilitation Sciences at The University of Queensland. Margaret has also been nominated as a candidate for the position of President of the International Ergonomics Association.
Births - the Queensland branch is expanding through recent reproductive efforts of Sharon Goodwin (Danyon) and Roxanne Egeskov (Samuel).
Roxanne writes on the Ergonomics of Parenthood....
"As each day unfolds, I am confronted by the risks and unique ergonomics issues relating to having and caring for newborn child.
The first dilemma was the purchase and selection of furniture and equipment. After test driving almost 35 prams, reviewing numerous change tables and cots, the appropriate slections were made - he is undiputably the child of an ergonomist!
Emergency procedures were established and trialed for "the event" - thankfully too, as a 1.5 hour time frame left little time for delays. For my next child I'm camping in the car park of the hospital one month before it's due !!!
Education, training, information sessions and copious advice from family, friends and strangers has adequately equipped me with knowledge and skills to deal with unique happenings with a newborn. Not always though - no-one told me about: (i) onions and cabbage causing sleepless nights, (ii) projectile vomiting, or (iii) the unpredictable aim of little boys!
Shiftwork and sleep deprivation has had a profound physiological and psychological effect on both parents. I now have significant memory loss, reduced tolerance, far less energy and an increased risk of accidents - I now write important things down and eat off plastic.
Exposure to copious bodily products and fluids has enforced my procedures for hygiene and personal protective equipment - I carry spare sets of clothes everywhere.
And as I continue to discover how my skills and knowledge as an ergonomist apply to my new career, I ponder the year ahead...the positives and the negatives. As my little boy looks and smiles at me, I know it is all worth it - I also know it is only wind!"
Shann Gibbs <shanng@gibbsplus.com.au> writes:
I was thrilled to receive a fax from CIDEM (Centre for research and development of drugs) in Cuba a few weeks ago inviting me for a one week stay to collaborate in "assistance concerning waste and other aspects related to cytostatic drugs". They would "take care of lodging and food expenses, as well as plane tickets (including return flight) from Canada to Havana" but could not afford the full fare from Australia.
This followed a request from them last year for a copy of a paper I had published in AJHP in 1989, and then a request for an update on my work once they had received it. I thought the contact had fizzled out. Cuba must be the most difficult location on the planet for telecommunications - so far no joy with email (I keep suggesting it but get no answer as may be it is not available?) and while their fax gets to me, the delay cuts out anything going from this end and I must have had a dozen "line errors" or "communications errors" and end up posting everything ... heaven knows what route it takes to get there airmail as nothing direct to Cuba except from Mexico and no direct flights from here to Mexico; seamail would be en route still, presumably!
Having self-funded all my research, including trips to USA, Europe, UK and Malaysia I've exhausted my coffers, but would love to help them. The foreign desk in Canberra tells me that OZ is concentrating on funding efforts in Asia-Pacific and Cuba does not feature; they gave me the contact numbers for the Cuban Consul-General in Sydney; after phoning him and at his request faxing him a copy of the CIDEM fax plus my thesis precis, he phoned and arranged to visit me the next day! He assures me that I must go to Cuba; he has offered to liaise directly as he returns to Cuba next week and will take a survey I have prepared, as well as brief his successor here to maintain contact.
I just wondered if any of our ESA members would have some ideas about contacts for possible help with plane fare to Mexico/Canada as CIDEM would then get me to Havana; eg is WHO a likely source? It is such a large organisation it would be useless to try unless a personal contact is known. Any other ideas? Even if it is not possible to go I have been extremely flattered to have been invited ...(and encouraged - at a time when full of self-doubt while writing up and having violent mood swings about whether the whole project is important or a waste of everyone's time and effort!)
Shann
Is it Always a Good Idea to Design an Interface to Match the Operator's Mental Model?
Kim J. Vicente
University of Toronto, Canada.
INTRODUCTION
Human factors professionals know that it is always important to design a human-computer interface to be compatible with the operator's mental model of the system to be controlled. Or is it? In this article, I will critically examine this cognitive compatibility principle to determine if it is valid and useful for all types of application domains. In particular, I will evaluate its usefulness for work domains that impose dynamic, objective, environmental constraints (e.g., the positions of other aircraft and the terrain in aviation, and the laws of physics governing a nuclear power plant) on the goal-directed behavior of human operators. Following Vicente (1990), these work domains will be referred to as correspondence-driven. To anticipate, I will conclude that in these cases cognitive compatibility is impotent without first establishing ecological compatibility.
THE COGNITIVE COMPATIBILITY PRINCIPLE
Example #1
In a review of advanced alarm and diagnostic systems for nuclear power plants, Kim (1994) provides a clear statement advocating the cognitive compatibility principle: "the computerized systems for on-line management of plant anomalies must provide the operators with representations of plant functions that are compatible with their mental image of the plant, the so-called mental model or conceptual model" (p.293). This may seem like a logical and defensible claim, but it overlooks an important factor. What if the operator's mental model is incomplete, or even worse, incorrect in the sense that it does not faithfully capture how the plant actually works? Given the human factors design inadequacies in existing control rooms, and the fact that the control room design can shape operators' mental models, one can hardly take it for granted that deficiencies in operators' mental models do not exist. How useful would it be, then, to design an interface that is consistent with an operator's mental model but that describes the plant in a way that is incorrect or incomplete? The answer to this question should be self-evident since the laws of physics are unforgiving.
For those who remain unconvinced, however, an anecdote from the nuclear industry should help to illustrate the limitations of the cognitive compatibility principle. One nuclear power plant vendor chose an exceptionally skilled operator to participate in the design of a new control room. This practice is consistent with existing theories of "participatory design" or "user-centered design", the goal being to get user input into the design process. This is a laudable goal and represents a distinct improvement over traditional design practices which essentially leave the user out of the design process. Nevertheless, the moral of this anecdote is that it is possible to take this user-centered approach too far. When the new control room design was shown to other operators, the designers quickly realized that the design process they had adopted was faulty. The first valuable lesson they learned was that other operators did not think of the plant in the same way as the exceptional operator who was part of the design team. In fact, no two operators seemed to have the same mental model of the plant. This finding caused the designers to reflect more deeply upon the relationship between operators' mental models and the engineering laws and principles governing plant behavior. This reflective exercise revealed another valuable lesson, namely that all of the operator's mental models were limited in the sense that they contained misconceptions, omissions, or both. As a result, the control room in question had to be redesigned to reflect better the way in which the plant actually worked. Needless to say, this was a costly and time-consuming process.
Example #2
Some readers might think that this critique of cognitive compatibility is self-evident. If this is the case, then one would expect that all prominent human factors theories would have incorporated these considerations. To determine whether this is the case, let's examine briefly the well-known proximity compatibility principle (PCP) (Wickens &Carswell, 1995). In a nutshell, the PCP states that the perceptual characteristics of displays should be designed to be compatible with the cognitive processes used by operators to perform a particular task. For example, if operators use two sources of information to complete a task,then the display should somehow integrate these data for the operator. Conversely, if the operator focuses on a single source of information to complete a task, then that datum should be presented so that it is separate from other data.
It is clear from the applications that have been chosen to evaluate the PCP (e.g., aviation, process control) that it is intended to be applied to correspondence-driven work domains. Nevertheless, Wickens and Carswell (1995) clearly advocate the cognitive compatibility principle. For example, in defining various forms of task proximity (which, according to PCP, dictate what type of displays should be designed), Wickens and Carswell (1995) discuss the concept of functional similarity, which they state "refers to the similarity of the units or objects being measured, as represented in the operator's semantic space" (p. 476, emphasis added). They then go on to state that "functional similarity could be derived from multidimensional scaling techniques eliciting the structure of the operator's semantic space or mental model of the displayed system" (p. 476, emphasis added).
These recommendations made by the PCP are subject to the critique already presented above. Focusing on cognitive compatibility overlooks the fact that the operator's mental model may be incorrect or incomplete. Furthermore, basing a display on a "buggy" mental model can be a costly mistake, as the anecdote from the nuclear industry made clear.
Conclusion
The cognitive compatibility principle focuses so much on the characteristics of the human operator that it virtually ignores the characteristics of the system being controlled. This can be a significant problem in correspondence-driven work domains that impose dynamic, objective, environmental constraints on productive operator behavior.
What might be the cause of this oversight? The reason seems to be that the cognitive compatibility principle is based on an information processing approach to human factors (e.g., Wickens, 1992). This approach begins with, and devotes most of its theoretical energy to, analyzing and describing human characteristics. As a result, the information processing approach tends to underemphasize the design relevance of the environment in which behavior takes place. This can be seen by contrasting the traditional information processing approach with a more recent alternative, the ecological approach to human factors (Flach, Hancock, Caird, & Vicente, 1995; Hancock, Flach, Caird, & Vicente, 1995).
THE ECOLOGICAL APPROACH
The ecological approach to human factors is based on the concepts developed within ecological psychology (Brunswik, 1956; Gibson, 1979). Interestingly, this approach has strong ties with systems engineering as well (cf. Meister, 1989). More important for the purposes of this article is the fact that the ecological approach has several characteristics that distinguish it from traditional approaches to human factors based on information processing psychology (Vicente, 1995). Whereas more traditional approaches (e.g., Wickens, 1992) tend to put a great deal of emphasis on analyzing human characteristics, the ecological approach (e.g., Rasmussen, Pejtersen, & Goodstein, 1994) puts much more emphasis on analyzing the interaction between people and their environment. It is important to note that the term "environment" here is used in a very broad sense. Depending on the domain of application and the question of interest, the environment can be the physical properties of a workplace (e.g., lighting, heat, humidity), the demands of the tasks that people are required to perform (e.g., landing vs. take-off in aviation), the structural characteristics of the work domain people are interacting with (e.g., flexible manufacturing system, nuclear power plant), the values and organizational structure of the company they work in (e.g., safety culture, matrix organization, respectively), and even the nature of the climate that governs the particular industry of which people are a part (e.g., how tightly regulated the industry is, how many companies are competing for the same market). One of the fundamental commitments of the ecological approach is that it is not possible to understand human behavior without simultaneously understanding the environment in which people are acting.
Consequently, the ecological approach demands that we explicitly analyze the constraints that the environment imposes on behavior (in addition to investigating the characteristics of people). Even more strongly, however, the ecological approach claims that it is important to begin by analyzing the environment before analyzing what people are doing, or how they are doing it, or what they know. This provides a strong contrast to the information processing approach to human factors, which focuses primarily on the individual. This difference can be observed in the familiar flow diagrams illustrating the various stages of human information processing (e.g., sensation, perception, attention, working memory, long-term memory, decision making, problem solving, planning, motor control). Not only does the environment in which behavior take place not play a central role in these diagrams, but in many cases, the environment is not even explicitly represented (except perhaps in a very spartan manner by a feedback loop from motor control to sensation).
Relevance to Interface Design
What does the ecological approach have to say about how interfaces should be designed for correspondence-driven work domains? Instead of focusing exclusively on cognitive compatibility, this approach suggests an ecological compatibility principle: the design process should begin by ensuring that the content and structure of the interface is compatible with the constraints that actually govern the process to be controlled. In doing so, the goal is to ensure that operators will acquire a veridical mental model of the work domain, so that their understanding corresponds, as closely as possible, to the actual behavior of the system. This is not to say that psychological considerations are not important. Whereas the content and structure of the interface is dictated by ecological considerations, the form of the interface should be designed to be cognitively compatible with the properties of human cognition, action, and perception.
One can generalize this argument to any application domain where there is an external reality -- outside of the person and the computer -- that imposes dynamic, goal-relevant constraints on meaningful behavior (Vicente, 1990). For these correspondence-driven work domains, operators' mental models should correspond with this external reality and thus the interface should be based on the ecological compatibility principle. There are many examples of such domains aside from the prototypical example of nuclear power. To take but one, in aviation it is important that pilots' mental models of how the aircraft functions, of geometric constraints in 3-D space, and of the flight management system (FMS) be accurate. Thus, interfaces displaying the status of aircraft systems, air traffic, and the FMS should be based on the constraints that describe how these entities actually work, not on how pilots might think that they work. Adopting the cognitive compatibility principle would support the operator's mental model, but would eventually lead to a rude awakening when the pilot's assessment of a situation does not correspond to what is actually going on.
POTENTIAL COUNTERARGUMENTS
To avoid any misconceptions, it is important to address head-on several potential objections to this critique. First, it could be argued that I have presented a straw man. After all, how could anyone possibly advocate designing an interface based on a grossly incorrect operator mental model? The only way to determine if I have misrepresented others' views is to look closely at the words they use. It is certainly true that neither of the papers in the two examples cited above directly state that interfaces should be designed according to system models that are incorrect or incomplete. However, it does not follow that those papers reflect an appreciation for the importance of the ecological compatibility principle. The fact of the matter is that Wickens & Carswell (1995), for instance, never explicitly state that a display should be designed to be compatible with the way the system actually works. Moreover, the words that they do use (see above) indirectly conflict with such an assertion.
Second, it could be argued that operators' mental models do not have be exactly accurate. As long as they are "close enough", then performance may not suffer. This may be true for the set of situations that operators encounter frequently and to which they have adapted. However, accident analyses have repeatedly shown that when unfamiliar, abnormal events that are outside of operators' adaptation boundaries occur, the divergence between operators' mental models and the actual behavior of the system becomes practically significant and greatly jeopardizes system safety (Rasmussen, 1986). Thus, "close enough" may be good enough most of the time, but in systems where the consequences of error have enormous financial, safety, and environmental implications, a more cautious and thorough approach to interface design is required.
Third, one could argue that there are several different correct mental models for any system with objective characteristics. This is absolutely correct but it does not invalidate the critique of cognitive compatibility presented above. After all, just because there are several equally faithful mental models does not mean that designers can assume that operators have one of those models. It is always important to make sure that the system model serving as the basis for interface design captures the way in which the system actually works.
This latter point opens the way for integrating ecological compatibility and cognitive compatibility. It should be clear by now that cognitive compatibility is of little use unless ecological compatibility has already been established. That is, making an interface compatible with an operator's mental model will not do much good if that model does not correspond with the way the system actually works. However, given that ecological compatibility has been ensured, cognitive compatibility provides a useful way of closing the remaining degrees of freedom in interface design. Bringing together these two principles in this order is productive because it ensures that interfaces will present operators with the information they need to develop accurate mental models in a form that is compatible with existing knowledge of human cognition.
CONCLUSION
Designing a human-computer interface so as to be compatible with the operator's mental model of the system to be controlled is inappropriate for applications domains where there is an objective reality imposing dynamic, goal-relevant constraints on meaningful behavior. In these cases, it is more appropriate to begin the design process by creating an interface that is compatible with the actual constraints of the environment. Only then will have cognitive compatibility have any potency as a design principle. This observation follows directly from the ecological approach, and shows the limitations of the more traditional information processing approach to human factors. Moreover, this illustrates that the ecological approach can make significant contributions to our discipline that build upon those of more traditional approaches.
ACKNOWLEDGEMENTS
The writing of this article was sponsored by grants from the Natural Sciences and Engineering Research Council of Canada. I would like to thank Jeff Landis for his kind invitation, Cathy Burns for suggesting the theme for the article, and an anonymous reviewer for vigorous yet constructive criticisms.
REFERENCES
Brunswik, E. (1956). Perception and the representative design of experiments (2nd ed.). Berkeley, CA: University of California Press.
Flach, J., Hancock, P., Caird, J., & Vicente, K. J. (1995). Global perspectives on the ecology of human-machine systems. Hillsdale, NJ: Erlbaum.
Gibson, J. J. (1979). The ecological approach to visual perception. Boston, MA: Houghton-Mifflin.
Hancock, P., Flach, J., Caird, J., & Vicente, K. J. (1995). Local applications of the ecological approach to human-machine systems. Hillsdale, NJ: Erlbaum
Kim, I. S. (1994). Computerized systems for on-line management of failures: A state-of-the-art discussion of alarm systems and diagnostic systems applied in the nuclear industry. Reliability Engineering and System Safety, 44, 279-295.
Meister, D. (1989). Conceptual aspects of human factors. Baltimore, MD: Johns Hopkins University Press.
Rasmussen, J. (1986). Information processing and human-machine interaction: An approach to cognitive engineering. Amsterdam: North-Holland.
Rasmussen, J., Pejtersen, A. M., & Goodstein, L. P. (1994). Cognitive systems engineering. New York: Wiley.
Vicente, K. J. (1990). Coherence- and correspondence-driven work domains: Implications for systems design. Behaviour and Information Technology, 9, 493-502.
Vicente, K. J. (1995). A few implications of an ecological approach to human factors. In J. Flach, P. Hancock, J. Caird, & K. J. Vicente (Eds.), Global Perspectives on the Ecology of Human-Machine Systems, (pp. 54-67). Hillsdale, NJ: Erlbaum.
Wickens, C. D. (1992). Engineering psychology and human performance (2nd ed.). New York: Harper-Collins.
Wickens, C. D., & Carswell, M. (1995). The proximity compatibility principle: Its psychological foundation and relevance to display design. Human Factors, 37, 473-494.
Author Biography
Kim J. Vicente received a Ph.D. (1991) in Mechanical Engineering from the University of Illinois at Urbana-Champaign. He is currently an assistant professor of Mechanical & Industrial Engineering and of Biomedical Engineering at the University of Toronto, and director of the Cognitive Engineering Laboratory there.
[Editors note: to attempt to promote discussion of the issues raised by Kim Vicente, I sent the paper to a couple of ESA members with interests in the design field. Any other members who would like to contribute additional comment for inclusion in Ergonomics Australia On-Line are most welcome to do so.]
Commentary on Vicente (1997) Is it Always a Good Idea to Design an Interface to Match the Operator's Mental Model?
Bill Green,
Professor, Design, Applied Ergonomics and Product Safety
Faculty of Industrial Design Engineering, TUDelft.
email: W.S.Green@io.TUDelft.nl
Thanks for sending on the article by Kim Vicente - "Is it always a good idea to design an interface to match the operator's mental model?" I read it with great interest and make these off-the-cuff comments.
I think Kim Vicente is absolutely right to question the cognitive compatibility approach to interface design. There is an assumption implicit in such an approach that (a) it is possible to construct an accurate mental model for the operator and (b) that such a mental model has some inalienable effectiveness. Why is it surprising that what is essentially a human characteristics based strategy fails to predict what actually happens?
His example from the nuclear industry is evidence of the primitive understanding of 'user-centred' design which exists. Would any serious researcher accept such a manifestly biased input into a design process?
The ecological approach, whilst undeniably attractive, may also be inadequate, depending on the particular definition one applies to it. Vicente quite properly notes the inevitable presence of "dynamic, goal-relevant constraints on meaningful behaviour" and my emphasis would be on 'dynamic'. We have found that attempts to generalise user/object/environment outcomes are extremely problematic. There is a high degree of specificity at what may be called the edges of the interface, and it is at these edges (physical/conceptual/perceptual/cognitive) where the problems occur. Thus predictability of use may, as Vicente says, be good enough most of the time, but all that does is allow 'normal' operation. By definition (we hope!) things don't go wrong in 'normal' circumstances. Direct observatiom of users, with the product, in the environment, is a way of gaining insight of the way things actually happen, which may be independent of the predictions of any single set of mental or environmental models. If the 'ecological' definition encompasses this, then I support it fully.
An accident is by definition an event without predictable cause. The best we can do is to combine available information on human characteristics and environmental characteristics with observations of user behaviour into a compendium of data with which to inform product and systems designers. Even then, it would be naive to suppose that (a) the data are adequate, (b)they are translated effectively, and (c) that Murphy's Law will not apply anyway! It is clear, though, that there are many other problems - of inefficiency, discomfort, irritation - which are this side of an accident but which nonetheless deserve design address.
Kim Vicente takes a supportable stance. It is not new in academic terms, but interaction design needs as many people of Vicentes persuasion saying it as often as possible.
Bill Green seems to agree with my thesis but for different reasons than I originally gave to support it. For example, he questions the assumption that "it is possible to construct an accurate mental model for the operator". Unless I am missing something, I firmly believe that this can be done. Moreover, it must be done if one is to follow the ecological compatibility principle. A normative mental model of the domain must be developed, and then built into the interface, if we are going to have ecological compatibility. Similarly, Green questions the assumption that "such a mental model has some inalienable effectiveness". Again, unless I am misinterpreting what he is saying, I do agree that such a mental model is absolutely critical if operators are able to effectively problem solve when they encounter unfamiliar or unanticipated situations. It seems to me that the only way to deal with such situations is to reason effectively based on a veridical representation of how the system in question is supposed to work.
Having said that, I agree wholeheartedly that the current understanding of what it means to be user-centred is primitive. Different people mean different things by this term, and as I tried to show, not all of these views are particulary productive. We need to come to grips with this terminological and conceptual muddle in our discipline.
As for the generality of the ecological approach, the environmental model I envision using is based on Gibson's (1979) concept of affordances. It describes the actual possibilities for action in the environment, i.e., the various productive ends to which the system can be put to use. As a result, it should encompass the subset of uses which are observed in descriptive observations of actual user behaviour.
Finally, I disagree with Green's view on supporting people during accident situations. It is in fact possible to design systems that support people in events that are unfamiliar to them and that have not been anticipated by system designers. The rationale for this claim can be found in Vicente & Rasmussen (1992) and Bisantz & Vicente (1994), so I will not repeat it here. In a nutshell, what we need are not more data but better models because (in correspondence-driven domains, at least) there are an infinite number of abnormalities that can occur. We can never collect enough data to address them all. The alternative is to adopt a model based approach that will support people in adapting to unforeseen contingencies. As Bateson (1979) pointed out "the generic we can know, but the specific eludes us" (p. 45).
REFERENCES
Bateson, G. (1979). Mind and nature. New York: Dutton.
Bisantz, A. M., and Vicente, K. J., "Making the abstraction hierarchy concrete," International Journal of Human-Computer Studies, vol. 40, pp. 83-117, 1994.
Gibson, J. J. (1979). The ecological approach to visual perception. Boston: Houghton-Mifflin.
Vicente, K. J., and Rasmussen, J., "Ecological interface design: Theoretical foundations," IEEE Transactions on Systems, Man, and Cybernetics, vol. SMC-22, pp. 589-606, 1992.
Gitte Lingaard
Gitte Lindgaard & Associates Pty Ltd
e-mail: glindgaard@acslink.net.au
It is invariably easier to comment on other people's work than to generate new ideas. Having been asked by the editor to comment on Vicente's article in order to open up discussion, I am in the very fortunate position that I can pick and choose the topics I think could get the discussion going. My comments are therefore directed more at facilitating discussion than being a direct critique of Vicente's contribution.
Having said that, there are three issues in Vicente's article that I would like to take up. the first is the issue of ecological approaches vis [[daggerdbl]] vis, for example, information processing, or cognitive analyses as a basis for designing interactive systems. The second issue of mental models and cognitive processes concerns the confusion about form and process. The third issue concerns user centred design philosophy. I want to explore briefly what it is, how it is practised, what its limitations are.
In defending the ecological approach, Vicente tells us that it is best to start the user interface design of a complex interactive system that is compatible with the actual constraints of the environment within which it will eventually reside. I doubt anyone could disagree with that. However, the gist of his argument seems to suggest that Wickens and Carswell (1995) are presenting the proximity compatibility principle (PCP) as an alternative to the ecological approach advocated by Vicente. In fact, Wicken and Carswell say in their article that "we believe that the PCP is complementary to recent principles of ecological interface design, not in competition with them..." (1995, p. 474). In other words, they do not advocate that PCP replace the ecological approach, as one could be led to believe from Vicente's contribution.
Vicente does point out that the PCP, or indeed any human information processing theory, is too narrow and limited to be used as a sole basis for designing user interfaces to complex interactive systems intended for complex, uncertain environments. Again, I don't think anyone would disagree, and I wonder at the importance of such a statement. It is not a matter of taking sides, favouring one and disregarding the other, but rather one of understanding the merits and limitations of a variety of techniques and approaches in their application to a range of problems.
What bothers me about Vicente's thoughts on ecological approaches to interface design is that we HF folks seem continually to rediscover issues and principles that should be part of our basic knowledge base, both for theoreticians and practitioners. Vicente is by no means alone in this. In his recent collection of short essays, David Meister repeatedly asks: Where are the "new" ideas in HF? "Any "bright" ideas that will enable us to solve the many problems that we have, such as the inability to predict human performance, to relate these predictions to design parameters, the lack of validation for our methods and study conclusions?" (Meister, 1996, p.150).
Vicente gives due credit to Egon Brunswik who, in the 1950s pursued his philosophy of `probabilistic functionalism' which led him to study successes and failures of organisms in an uncertain environment (Slovic & Lichtenstein, 1971). Brunswik realised that psychology is not only about people who emit behaviour; it is also about the tasks that elicit behaviour. that is, the task-relevant characteristics of the environment are a necessary part of every process theory in psychology (Edwards, 1971). Brunswik's theoretical orientation was thus committed to an analysis of the interrelation between the organism and the environment and he was primarily interested in the organism's ability to absorb the characteristics in an uncertain probabilistic environment and to use his knowledge to his advantage. Brunswik (1955) was the first to make explicit the fact that modelling tasks is different from modelling people, to devise tools for modelling tasks and to provide links between models of tasks and models of people.
The 1970s brought a strong interest in judgmental `bootstrapping' when it was discovered that models based on an individual's own judgments attained a higher level of predictive accuracy than the person on whose judgments the model had been produced. In other words, people were being outperformed by their own very simple, linear models, and only minute changes to the judgmental conditions resulted in vastly different judgments. This finding ought to have emitted warning signals regarding the usefulness, durability and reliability of `mental models'. Alas, the mental model industry is still alive and well in the 1990s, an issue we shall return to in a moment.
The 1980s taught us that interactive computers live in work or play environments which have quite an impact on tasks, user interface design, and the technologies we choose to represent tasks. Human-computer interaction (HCI) was not, we learned, the fertile grounds for verifying psychological theory as had so enthusiastically been hoped in the early 1980s. Instead, it was realised that good interface design requires input from a range of professionals like sociologists and anthropologists whose base encompasses more than a single individual interacting with a single terminal. Apparently, we rediscovered Brunswick's realisation that context cum environment is extremely important.
Most recently, with increasing public concern about VDT work-related musculoskeletal disorders, interest in the mechanisms underlying repetition injuries and other musculoskeletal disorders has again risen. In an editorial of Applied Ergonomics (Winkel & Westergaard, 1996), the editors suggest that their "thorough review of the literature shows that Ergonomists are often unsuccessful" and that "musculoskeletal disorders may be prevalent in work places where large ergonomic resources have been invested" (p. 71). They argue that this points to the significance of other factors in addition to those that are commonly associated directly with musculoskeletal discomfort in the upper extremities.
According to these same authors, the literature shows that many documented interventions against occupational musculoskeletal disorders are unsuccessful (Westergaard & Winkel,1996). One reason, they suggest, is that Ergonomists generally intervene only against a minor fraction of the problem, such as concentrating on individual factors, or work station and tool design, including keyboards, but leaving out the basic problems of work, job, and task design. Brunswik's 1950s message again reminds us in the 1990s that we cannot afford to ignore the environment in which equipment and systems reside.
Meister (1996) suggests that we need to establish a database of past studies to see what they tell us that might help shed light on currently `hot' issues and problems. Doing this, he argues, is extremely difficult because our collective HF database is fragmented and disorganised, perhaps covering up a knowledge base that may be found, on closer scrutiny, to comprise a few facts and a lot of speculation. Is, as Meister asks, "our generation too self-satisfied, too smug, to challenge the foundations of our discipline? It requires, he asserts, a sort of intellectual bravery to challenge the general complacency. But without the challenge it is possible there will be no progress" (p.151).
Many definitions of mental models have been proposed over time. Toffler says that it is a "subjective representation of external reality" (1970, p. 139), which is consistent with Rasmussen's (1979) definition saying it is an "internal representation of the properties or constraints in the environment which determine the interrelation among the data which can be observed from the environment: (p. 10). Such representations consist of images ranging from mental pictures of concrete objects to abstract conceptions and inferences about structures and functions of complex systems. The construct evolves over time and is believed to be modified as knowledge increases.
Since a mental model is a subjective representation, the strategies preferred by one person may differ substantially from those preferred by another, equally knowledgeable person. Efficient use of a system can thus be achieved in various ways. Hence, there is not one single `correct' mental model of a given system. An expert may be able to describe a system's structure and functions in detail, but he cannot describe his mental model of the system in the same detail, because he does not have direct access to his own thought processes, and because there are many concepts which cannot be verbalised. Mental models are thus hypothetical constructs that must be described by inference from behaviour and performance because they cannot be readily observed.
Vicente acknowledges that mental models are likely to be deficient or incomplete, and he provides an anecdotal example demonstrating an instance in which a system was designed on the basis of an expert's incomplete mental model.
At the same time, there seems to be some confusion about the notion of mental models as a framework for operation and cognitive processes. Vicente says that "the PCP states that the perceptual characteristics of displays should be designed to be compatible with the cognitive processes used by operators to perform a particular task. For Example, if operators use two sources of information to complete a task, then the display should somehow integrate these data for the operator." Later he states that "...operators' mental models should correspond with this external reality and thus the interface should be based on the ecological compatibility principle."
The way in which the perceptual processes that are necessary to perform a given operation are supported says nothing about the frame of reference, or the mental model, that operators possess or should possess. Processes are not synonymous with the framework within which they operate, and the degree of correspondence between the two may be largely irrelevant from the point of view of supporting effective performance. Similarly, the fact that the ecological compatibility principle is a reasonable point of departure for interface design does not imply that, therefore, operators' mental models must adhere to a certain prescribed formula.
Returning for a moment to judgmental `bootstrapping' as discussed earlier. Because the level of predictive accuracy of the bootstrapping models was found to be very high, some researchers erroneously believed they had captured the respective judge's decision processes, or his mental model. Being able to predict output from knowledge of the input yields no information about the intervening processes; at least some of these processes are left unexplained. Evaluation of input and output can serve to estimate the effectiveness of a given model or metaphor in a certain context, which can be valuable in a practical sense. Because such findings are not generalizable beyond the given context, these evaluations are of little theoretical value; they are insufficient for the researcher who is seeking to understand the psychological processes that people use in certain interactive computing tasks.
If we can accept that a mental model is `owned' by an individual, that the properties of such a model change as knowledge increases, and that neither the properties nor the boundaries of the model are directly observable, it would seem inefficient to base the design of a system to be used by many individuals on the inferred mental model belonging to one individual. Vicente does acknowledge this, but he seems to believe that this is only true for the highly complex system types which he addresses. In fact, the same would be true for all systems, and indeed, all kinds of equipment design. No one would recommend designing a tool or a piece of equipment based on a sample of one! Therefore, the whole notion of mental models as a basis for design is of very little practical value and should be discarded.
User centred design is another much abused term. While Vicente claims that his anecdote is an example of user-centred design having been taken too far, I would argue that it has not been taken far enough!
Participatory, or user centred, design philosophy certainly seeks user involvement in the systems design and development process. But the idea is first, that several user representatives be involved, and second, that this involvement does not replace the iterative design-test-redesign cycle. As was suggested above, a sample of one is neither workable nor acceptable.
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Reply to Lingaard
Kim Vicente
Usually, the goal of a conceptual critique like the one I wrote originally is to try to correct some misconception which the author perceives to exist in a particular research community. Many times, responses to such efforts are perceived by the author of the original piece as not quite getting the point of the critique. This can be caused by one of at least two reasons: a) the original author did not write his critique clearly enough; b) the original author was justified in writing the original critique since there is in fact a deeply embedded misconception in the research community that is not easily rectified. Partialling out these two effects is difficult, so I am grateful for the chance to get my message across more clearly. What follows is a list of clarifications that respond to specific points made by Lindgaard.
1. Lindgaard doubts that anyone could disagree with my claim that it is best to start the design of an interface for a correspondence-driven system by ensuring that that interface is compatible with the actual constraints of the environment within which it will eventually reside (i.e., the ecological compatibility principle). One might think that this would be the case. However, if one closely examines the quotes I cited from both Kim and Wickens & Carswell, it is clear that they both recommend that the interface by compatible with the operator's mental model. If we assume that operators' existing mental models are either incomplete or incorrect in a substantive way (which seems extremely likely, given that existing interfaces tend to be quite poor), then the recommendations made by Kim and by Wickens & Carswell clearly conflict with the ecological compatibility principle I advocated. Of course, we do not know what Kim or what Wickens & Carswell would say if we asked them directly if they disagreed with the ecological compatibility principle. As scientists, what we can do is closely examine the words they use. In this case, there seems to be a clear conflict, despite what Lindgaard states. Furthermore, the fact that Wickens & Carswell view their ideas as complementary to my own, as Lindgaard correctly observes, is not of central importance because it does not change the fact that the words that Wickens & Carswell use directly conflict with the ecological compatibility principle, given the empirically verifiable assumption listed above.
2. Lindgaard also goes on to state that nobody would disagree with my claim that human information processing theories ares too narrow and limited to be used as a sole basis for designing interfaces for correspondence-driven domains. She also adds: "I wonder at the importance of such a statement". The importance of such a statement is that people have been advocating approaches to design based on an information processing perspective for several decades, and that many of these approaches do not make reference to some of the factors that Lindgaard thinks are obvious to everyone. If they are in fact obvious, then one should find them in every paper and book. But as I mentioned above, this is not the case at all. This needs to be pointed out, so that researchers and designers do not overlook the factors that are not explicitly considered in the information processing approach.
Having said all this, I agree completely with Lindgaard that "it is not a matter of taking sides, favouring one and disregarding the other, but rather one of understanding the merits and limitations of a variety of techniques and approaches in their application to a range of problems". It is precisly for that reason that I limited my discussion to correspondence-driven domains (for a discussion of coherence-driven domains, see Vicente, 1990). This is also why I pointed out that: "This is not to say that psychological considerations are not important. Whereas the content and structure of the interface is dictated by ecological considerations, the form of the interface should be designed to be cognitively compatible with the properties of human cognition, action, and perception". I also ended my critique by pointing out a "way for integrating ecological compatibility and cognitive compatibility" and by observing that "bringing together these two principles in this order is productive because it ensures that interfaces will present operators with the information they need to develop accurate mental models in a form that is compatible with existing knowledge of human cognition".
3. Another aspect of my critique which "bothered" Lindgaard is that "we HF folks seem continually to rediscover issues and principles that should be part of our basic knowledge base". She also states that "Vicente is by no means alone in this", citing a recent book by Meister. I don't understand why Lindgaard thinks I am rediscovering anything because, in my critique, I cited the seminal works of Brunswik and Gibson and also acknowledged that the ecological approach to human factors "has strong ties with systems engineering as well", which is not a new discipline. I would hope that, given these references, nobody would interpret me as believing that I had discovered something new. And to come to Meister's defense for a moment, it certainly is unfair of Lindgaard to accuse Meister of rediscovering anything. On the contrary, as one of the pioneers who founded the discipline of human factors, Meister should be applauded for discovering, not criticized for rediscovering. In any case, just because an idea is not a new one, does not mean it is not worth repeating. The problems that Lindgaard points out with the lack of impact of ergonomics in reducing musculoskeletal disorders make my point. Old ideas are sometimes worth repeating when people don't seem to have gotten the original message.
4. In her subsequent discussion, Lindgaard seems to confuse the concept "mental model" with that of a "strategy": "Since a mental model is a subjective representation, the strategies preferred by one person may differ substantially from those preferred by another, equally knowledgeable person". Strategies and mental models are two different things, at least from my theoretical perspective (cf. Rasmussen, 1986).
Lindgaard continues, stating that "there is not one single 'correct' mental model of a given system". As I pointed out in my critique, I agree: "one could argue that there are several different correct mental models for any system with objective characteristics. This is absolutely correct but it does not invalidate the critique of cognitive compatibility presented above".
Lindgaard follows up with the claim that:
"there seems to be some confusion about the notion of mental models as a framework for operation and cognitive processes. Vicente says that "the PCP states that the perceptual characteristics of displays should be designed to be compatible with the cognitive processes used by operators to perform a particular task. For Example, if operators use two sources of information to complete a task, then the display should somehow integrate these data for the operator." Later he states that "...operators' mental models should correspond with this external reality and thus the interface should be based on the ecological compatibility principle."
I must admit I am very confused by this. In the first quote, I was pointing out the perspective advocated by Wickens & Carswell, which is why I stated "the PCP states". In the second quote, I was describing the alternative perspective I am advocating which is why I referred to "the ecological compatibility principle". Lindgaard sees confusion. I see a comparison between two different theoretical viewpoints that conflict which other.
5. Lindgaard also wants to distinguish mental processes from mental models: "The way in which the perceptual processes that are necessary to perform a given operation are supported says nothing about the frame of reference, or the mental model, that operators possess or should possess". I find this hard to understand. Mental models are the substantive content supporting reasoning. How can the reasoning process by divorced from the underlying knowledge base?
6. Finally, with respect to user centred systems design, Lindgaard's solution that several users be involved and that design should be based on the iterative design-test-redesign cycle does not solve the problem I identified. Using several users with conflicting mental models will not help one decide how a system really works, and therefore what model the interface should be supporting. Similarly, rapid prototyping followed by iterative testing and redesign may not capture all of the ommissions of relevant information in the interface. Frequently, it is only when events that are unfamiliar to operators and unanticipated by designers occur that such deficiencies become empirically observable. A good example, is the Three Mile Island control room. Despite years of daily operational "testing", nobody realized that the flowrate from the auxiliray feedwater system was not represented in the interface and that this can be a very relevant piece of information in certain critical situations. For safety-critical systems, an analytical approach to design is needed (Rasmussen, Pejtersen, & Goodstein, 1994).
REFERENCES
Rasmussen, J. (1986). Information processing and human-machine interaction: An approach to cognitive engineering. Amsterdam: North-Holland.
Rasmussen, J., Pejtersen, A. M., & Goodstein, L. P. (1994). Cognitive systems engineering. New York: Wiley.
Vicente, K. J. (1990). Coherence- and correspondence-driven
work domains: Implications for systems design. Behaviour and Information
Technology, 9, 493-502.
Last Word
Gitte Lindgaard
First of all, I think Vincente is owed an apology. The editorial guidelines under which we worked varied sufficiently to set us off in different directions. I had been specifically instructed to arouse the Australian readership into a discussion, taking as a starting point VincenteÕs article. Terms such as Ôno one would disagree that...Õ were therefore thrown in as a provocative invitation to persuade our readership to disagree and enter into the discussion. Well, that backfired! I managed instead to insult Vincente who adopted the level of formality one would in a different forum. For that he deserves an apology. For us it is a lesson suggesting that editorial guidelines need to be more accurately specified to avoid future misunderstandings and embarrassment.
My point about Human Factors folks rediscovering the past was not a shot at Vincente or anybody else. It is not wrong to dig out valuable lessons from the past. The problem is that so many of these valuable lessons keep on being forgotten or ignored - and then they have to be rediscovered. As a discipline we are not very good at accumulating knowledge by building on the past in a systematic, coherent fashion. What Meister (1996) advocates, and I agree wholeheartedly, is that we desperately need a coherent database that contains our collective knowledge base as well as our collective goals. If those things that we do know were collected in one place and were readily accessible, that ought to form much more fertile grounds for new bright ideas that might help solving our problems. A central database should also prevent lessons of the past slipping through the net. The energy expended in so many areas, as I was trying to point out, to rediscover what we should have known all along, is a sad observation of the state of our discipline.
Now, regarding mental models, mental strategies and pereceptual processes, I think Vincente and I actually agree more than we disagree. We may regard a complex system as an organism, be it a nuclear plant, a chemical plant, or a human body. My mental model of the organism would, in my terminology, be my understanding of its anatomy and physiology. I would have an anatomical picture of the different parts of the organism, where they are located relative to each other, and what functions and purposes they each serve in keeping the organism going. In terms of physiology, my understanding would relate to how the organism works and how it responds to various stimuli like increasing or decreasing the rate of water flow, oxygen intake, the mix of catalysts, and so forth. Both kinds of understanding may be complete or incomplete at various levels of accuracy.
When the organism malfunctions, it emits certain cues, or symptoms, that signal a deviation from the norm. My ability to take a proper corrective action to bring the organism back to a normal state depends on my ability to detect and interpret these cues correctly as well as knowing how to deal with the problem. My ability to detect the cues is partly a matter of their salience, the strength with which they present themselves, and partly a matter of me paying attention to them.
My failure to pay attention even to salient cues may or may not be indicative of my mental model of the organism being incomplete or inaccurate. The assumption that the underlying knowledge base is invariably activated or even referred to when diagnosing a problem does not hold, at least in the medical literature. We have known for some time that even expert medical diagnosticians select a salient symptom first as a ÔpivotÕ around which further evidence is gathered (Eddy & Clanton, 1982). That is, diagnosticians very quickly formulate a diagnosis on the basis of a perceptually salient symptom, jumping to conclusions before inspecting the full range of presenting symptoms and indeed without consulting their vast physiological, anatomical and medical knowledge base. This together with the tendency to seek confirmatory information (T, Doherty & Sweeney, 1977) to strengthen confidence in the diagnosis already made can result in wrong treatment. Cue selection and interpretation does thus not necessarily rely on correct reasoning, or mental processes, regardless of the completeness and accuracy of the underlying knowledge base, framework, or mental model.
Anecdotal evidence from observations of operators in an advanced petro-chemical plant suggests the same is true for these operators. Salient physical cues were found to be responded to very quickly in an Ôif X then YÕ rule-based, habitual fashion in a range of situations. In these situations there was no evidence suggesting that operators engaged in high level reasoning that one would expect if they were seeking causal explanations of the problem by consulting their underlying knowledge base. The mental processes by which they interpreted the perceptual cues and decided on a strategy to solve the problem at hand were not based on their overall understanding of the plant, but rather on incidental physical cues.
Indeed, so strong was this reliance on individual perceptual cues that the quality of product deteriorated so seriously that the manufacturer nearly lost their largest customers when the equipment in the control room was replaced by computer screens. The system had been developed on the assumption that faults were diagnosed via high level knowledge-based reasoning, but operator performance showed that this was not the case in a range of situations. And nor that this assumption been tested or even questioned (Lindgaard, 1995).
I belive this is saying that one can have a complete and correct mental model of the organism and still miss an important diagnostic cue or set of cues, depending on the way in which the diagnostician is framing the problem at the time. This frame is determined by a number of factors other than the full set of symptoms emitted by the organism and other than the underlying knowledge base of the organism. The relative frequency of occurrence of certain combinations of symptoms, similar cases that one has experienced or heard about, the severity of the outcome of a particular action, primacy and recency effects, and several others contribute forming to the present frame in addition to the mental model the diagnostician holds of the organism. Knowledge of an individualÕs mental model of the organism, and a direct mapping of it to the display that represents it, is therefore not enough to ensure that detection of cues signalling a deviation from the norm will always be perfect.
As a diagnostician my reading of the state of affairs still depends on my selection of cues from the environment. Perception is a cue selection process. Reasoning about the perceived cue comes later. The perception - reasoning - action sequence one would expect is often found to be replaced by a perception - action loop. Thus, it appears that perceptual processes needed to initiate corrective action can be divorced from reference to the underlying knowledge base.
Finally, regarding iterative testing, it is reasonable to argue that it does not help to decide how the system works, but rather how well the interface conveys to the user how the system works. I agree with Vincente that iterative testing per se cannot reveal how right the interface is, but only how wrong it is. To my mind that is essential information for designing more supportive computer systems.
Eddy, D.M. & Clanton, C.H. (1982). The art of diagnosis: Solving the clinicopathological exercise, New England Journal of Medicine, 306, 1263-1268.
Lindgaard, G. (1995). DCS usability in the Alkathene Plant, confidential report, ICI Engineering, Australia.
Meister, D. (1996). Divergent viewpoints: Essays on human factors questions, Unpublished manuscript.
Mynatt, C.R., Doherty, M.E. & Tweeney, R.D. (1977). Confirmation bias in a simulated research environment: An experimental study of scientific inference, Quarterly Journal of Experimental Psychology, 29, 85-95.
Participatory Ergonomics at Industry Level.
Max Hely
Physical Hazards Unit/BackWatch
WorkCover NSW, 400 Kent St, Sydney 2000
The value of participative approaches to ergonomics practice is becoming increasingly apparent, underpinned as they are by the active involvement of both workers and management in solving work problems. Ownership of the proposed solutions by the affected parties is considered an essential ingredient for the ultimate success of any ergonomic consultancy.
Cooperation between employers and employees of an individual workplace, when assessing occupational back injury risk, is mandated by the National Standard for Manual Handling. The BackWatch Program of WorkCover NSW is currently attempting to emulate that requirement in their broader arena of interaction with whole industries.
Back injuries are the largest occupational health and safety problem in NSW, accounting for approximately one third of all workplace injuries and workers' compensation costs. In 1992-1993, this amounted to $433 million. In 1994, WorkCover NSW undertook the BackWatch program as a major initiative aimed at reducing workplace back injury by engendering an increase in industry best practice, especially in regard to manual handling injury prevention.
Whilst the BackWatch program is wide ranging, incorporating enforcement and rehabilitation efforts as well, ergonomics plays a major role in one of the central program elements - the development of industry-specific "best practice" in back injury prevention.
The increasing complexity and diversity of work makes the successful generation of generic solutions less likely, and thus demands industry-specific approaches tailored to particular problems. When applied at industry level in this way, ergonomics has the clear potential to broadly and fundamentally influence the future design of work and workplaces, especially if operating in tandem with the development of standards, guidelines and recommendations of various kinds and, ultimately, in the interpretation of current and future regulations. Participation of industry representatives in these efforts is crucial if they are to play a part in influencing the shape of their industrial practices for the future.
The difficulty for a regulatory organisation involved in assisting industry is to determine how to address the specificity which sound ergonomics practice requires, yet be able to effectively, and impartially, assist industry as a whole. BackWatch approached this by first identifying those industry sectors with, statistically, the greatest need for assistance in reducing back injuries. Eight key industries have been targeted, including wholesale and retail trades, health, road transport, civil and building construction, the cleaning industry and local government.
Representatives from these industries were then invited to participate in expert working groups (a.k.a. BackWatch Action Committees, or BAC's) whose purpose is to provide the "expert user" input into the identification and assessment of, and the development of solutions for, the activities which, within each industry, appear to have the greatest impact on the production of back injuries.
The role of ergonomists in addressing these "high impact" activities in the targeted industries can be seen in the following examples :
Health
The ergonomic evaluation of patient lifting aids is one of the current major projects being undertaken for the health industry. Others include development of selection criteria for purchase of beds, investigation of linen handling systems, examination of patient assessment criteria, and floor material selection and cleaning practices.
Construction
A major project currently underway, is the evaluation of a prototype upright storage rack for formwork frames. Currently, formworkers need to lift the frames (which can weigh up to 60 kg.) from the ground. The upright rack, developed by an industrial design student, has been designed to minimise the manual handling risk factors in this work. A number of other issues are currently being assessed, ranging from the manufacture of supplied products (e.g., discontinuing use of 40kg cement bags), consideration of design issues to reduce awkward and constrained working postures, and training requirements for apprentices.
Retail
The varying characteristics of cashier workstations are of concern in the retail trades. Ergonomic expertise being applied to this question includes anthropometric assessments to determine the appropriate workstation design to accommodate physical and visual requirements when using conveyors, scanners, registers, bag units and cash drawers. Other factors being evaluated include the force requirements when moving trolleys and bagged products, floor surface requirements to minimise friction and fatigue, and the relationships between shiftwork and fatigue, and processing speeds and cognitive consequences, including mental workload and error.
Cleaning
The use of backpack vacuum cleaners is widespread, yet information is needed about their use, suitability, and manual handling risk potential. The current range of backpack vacuum cleaners is being assessed in terms of energy expenditure, comfort, useability, cleaning efficiency, and user preferences. Selection criteria which are being investigated for specific models include consideration of the user's anthropometric characteristics.
Road Transport
Loading/unloading and entering/exiting vehicles constitute major back injury risks for road transport workers. A variety of issues are to be evaluated, including the quality and availability of information resources to assist in the selection of appropriate manual handling equipment, design solutions to reduce access and egress difficulties which contribute to slips, falls, and jarring, and the effects of seat and cabin design, and operator technique, on exposure to shock and vibration when operating vehicles.
Benchmarking
An initiative applicable to all industries is the development of a manual handling risk management performance tool. This assessment tool will make use of performance indicators that are closely aligned with steps in the risk management process - consultation, hazard identification, risk assessment, etc. - and will also permit industry performance benchmarking. BackWatch ergonomists will soon be pilot testing a provisional set of measures to refine the system. Following this, WorkCover inspectors will commence using the tool as an aid to assessing compliance with the manual handling legislation.
Conclusion
The identification of high impact activities and the selection of projects or approaches to address these is by no means at an end. We are continuing to seek advice, suggestions, and criticism, about all aspects of the BackWatch program in order that we can more effectively tune our efforts to meet real industrial needs. Input along these lines is especially welcomed from ergonomists and other occupational health and safety professionals, as well as from representatives of management, workers, professional organisations, researchers, consultants, and any other individuals or interested parties.
Contact regarding BackWatch ergonomics work can be made with the author, Max Hely, or with fellow BackWatch ergonomists, Donna Lee, Steve Ward or Fiona Weigall, at WorkCover NSW (Ph. 9370 5993).
Disclaimer
This article reflects the views of the author and not necessarily those of Workcover NSW.
HEALTH & SAFETY TRUST
1998 GRANTS
APPLICATIONS NOW INVITED
The Australian Occupational Health & Safety Trust is established as a non profit making organisation the purpose of which is to provide grants to occupational health & safety practitioners.
These grants will be awarded for projects involving the development of occupational health & safety education/training material or for personal professional education.
The ultimate goal of any grant must be to improve the health & safety of people at work in Australia and therefore preference may be given to projects relating to the development of educational material due to its wider application in this area.
Written applications should state the objectives of the project, its methodology and how this will benefit people at work in Australia. Applications must conform to the Guidelines for Grant Applications, available from the Trust at the address below.
Applications will be judged on merit. The decision of the Trust will be final in all matters associated with the awarding of grants. Trustees are ineligible.
Upon receipt all applications will be acknowledged in writing.
The Australian Occupational Health & Safety Trust
PO Box R804
SYDNEY NSW 2000
Telephone: (02) 9220-6374
Closing date for applications - 30th September 1997
A selection of electronic resources.
A Check-List for Handle Design
Michael Patkin
Department of Surgery
The Whyalla Hospital, South Australia
There will always be a need for well-designed hand tools and hand operated controls despite newer technology. Good handle design is important at work and in all kinds of daily activities for items that are efficient to use, safe, and attractive to buy.
Anything that can picked up by the human hand or which the body comes in contact with is in some sense a handle. All these need some of the same features, whether it is a door or a doorhandle pushed open by the body, or a book or glass or box, or any of a hundred thousand other items.
The author of children's books about Peter Rabbit, Beatrix Potter, insisted her publisher made her books small, to fit the small hands of children, at the same time as the typeface was large to make reading easy. Like many expert and intelligent people she was an excellent intuitive ergonomist.
Newer demanding activities such as micro- and keyhole surgery have put more critical demands on hand-work than in the past. There is an even greater need to apply principles of good design to handles and understanding better how they are to be used.
There are other reasons for looking at the ergonomics of handle design for products. They are more likely to sell better when competing internationally with established manufacturers.
This article starts by looking at the common types of hand-grip, their features, and how they hold and use items. Most of the article consists of more than 50 criteria against which the design of a handle or hand-held item can be compared, and it includes ways of checking some features of handle design.
(Complete text available at http://www.uq.edu.au/eaol/apr97/handle.html)
Robin Burgess-Limerick (The University of Queensland)
and Elizabeth Bunker (Elizabeth Bunker & Associates)
The aim of this case study is to illustrate general principles of workstation design through examples taken from a walk through of a laboratory which provides on site quality control for a large minerals processing plant. The laboratory was undergoing extension and refurbishment and the walk through was conducted to identify areas deserving particular attention.
(full paper at - http://www.uq.edu.au/eaol/apr97/laboratory/laboratory.html)
A Case Study in Participatory Design: Incorporating Tools from Paper and Pencil to Virtual Reality
Hypermedia Technical Report HCIL-96-01
Authors: Snow, M. P., Kies, J. K., Neale, D. C., and Williges, R. C.
Date: April, 1996
(full paper available at http://hci.ise.vt.edu/~hcil/htr/HCIL-96-01/HCIL-96-01.html)
Australia New Zealand OHS Bibliographic Database (http://www.allette.com.au/~wsa1/wksafe21.htm)
The Australia New Zealand OHS Bibliographic Database includes bibliographic references for journal articles, monographs, reports or papers presented at conferences.
Abstracts are included for many of the entries in this searchable index. Thanks to Leon Straker for pointing this one out.
What do we plan or control when we perform a voluntary movement?
Gerald L. Gottlieb in Biomechanics and Neural Control of Movement, Winters and Crago, Eds., Springer Verlag, in press (1997)
(full text at http://www.ee.cua.edu/~bme_des/vi/gg/evi-gg.htm)
Management of an OH&S laboratory
A Paper presented by Barry Pratt, Director Occupational Health & Safety, The University of Queensland
(presented at a Training Program for managers of Indonesian OH&S Centres, Brisbane, March, 1996)
(full text available at http://www.uq.oz.au/ohs/OHLab.html)
American Industrial Hygiene Conference & Exposition (AIHCE) 1996 Abstracts are available at http://www.aiha.org/abstract/abindex.html
Relevant topics include:
Ergonomic Risk Factors and Their Effects on Performance
Ergonomics in Construction
Ergonomics Analysis Tools and Interventions
Ergonomics of Computer Workstations
Management Issues In Ergonomics
Poster Session - Ergonomics
Case Studies: Ergonomics and Indoor Air Quality.
Abstracts of particular interest include:
Comparison of Three Methods for Assessing Workload During Computer Use: A Pilot Study Among Transcriptionists. - M. Homan, T. Armstrong, C. Woolley, University of Michigan, Ann Arbor, MI
Effects of Low, Medium, and High Keyboard Stiffness on Typing Force, EMG, and Subjective Preference Among Transcriptionists.- M. Gerard, Center for Ergonomics, Ann Arbor, MI; T. Armstrong, W. Latko, B. Martin, The University of Michigan, Ann Arbor, MI
A Comparison of Hand-Arm Vibration Measurements for Selected Jackhammers and Vibration Isolation Materials. D. Heacock, Liberty Mutual Group, Pleasanton, CA; G. Hampel, E. Stevenson, Liberty Mutual Research Center for Safety, Hopkinton, MA
[Editors note: A case study prepared by some US consultants]
Ergonomic Job Analyses Of Picking Tasks In A Wholesale Grocery Warehouse Distribution Center.
Nancy E. Laurie M.S., Robert O. Andres Ph.D., CPE, David D. Wood M.S.I.E.
(Full paper available at http://www.ergo.engin.com/Articles.html)
The Effects of Multimedia and Elaborative Encoding on Learning
Lawrence J. Najjar
Georgia Institute of Technology, Graphics, Visualization, and Usability Centre (http://www.cc.gatech.edu/gvu/gvutop.html)
Complete text available at: http://www.cc.gatech.edu/gvu/reports/tr96/96-03.pdf
(portable document format, requires free adobe acrobat reader - http://www.adobe.com/prodindex/acrobat/readstep.html)
Edward Muybridge
[Editors note:- Another site for ergonomist's with a historial bent - a potted history of Edward Muybridge whose technological advances in the area of photography gave the science of biomechanics a substantial kick along.]
http://linder.deltanet.com/muybridge/muybridge.html
[Editor's note: The following is a press release from IBM. Would anyone care to provide a review of the information contained therein?]
IBM Unveils Healthy Computing Site On The World Wide Web. Site Will Focus On Personal Computing Ergonomics
SOMERS, NY, FEBRUARY 25, 1997 -- International Business Machines Corp. today unveiled the first World Wide Web site by a computer manufacturer entirely devoted to the discussion of ergonomic issues relating to the use of personal computers. The new site, Healthy Computing, can be accessed on the Internet directly at http://www.pc.ibm.com/healthycomputing, or via a link from the IBM PC Company home page at http://www.pc.ibm.com.
A properly designed computing workstation is essential to a user's comfort, job satisfaction. The Healthy Computing site addresses the important ergonomic elements of personal computing, including the set-up of a PC system and accessories to be proportional with human characteristics, vision and visual displays, and computing location, whether the user is working from home or the office.
The site also provides tips for healthy mobile computing, such as how to position a notebook PC for comfortable use on an airplane or in a hotel room.
Web users can easily navigate the site to find information that will help them to better understand their computing environment. It discusses the human optical system, vision disorders, corrective eyeware, and positioning of accessories such as a keyboard or chair to avoid bodily strain.
The proper set-up of a computing workstation takes knowledge and planning. Healthy Computing helps users to target their personal and physical requirements and provides them with the tools to design a comfortable workstation that suits their situation. "Healthy Computing digs deep into the heart of today's most important ergonomic issues and offers information, tips and solutions from personal computing experts," said Paul Snayd, program director, ergonomics, IBM. "The new Web site will enable PC users to establish a healthy and productive personal computing environment."
Tactical Display for Soldiers: Human Factors Considerations
Panel on Human Factors in the Design of Tactical Display Systems for the Individual Soldier, National Research Council, ISBN 0-309-05638-1; 1997
[Editors note: This book can be read in full at the National Academy Press web site, although the pages are only available as images, which makes it a slow process. http://www.nap.edu/readingroom/enter2.cgi?0309056381.html]
EMG tutorial
A tutorial (with nice graphics) on the detection and recording of surface electromyography by Carlo DeLuca, Boston University is available at http://nmrc.bu.edu/nmrc/detect/emg.htm
Contents
General
Characteristics of the EMG signal
Characteristics of the electrical noise
How can the fidelity of the EMG signal be maximized?
Electrical characteristics of the electrode unit and amplifiers
Electrode geometry
Where should the electrode be placed on the surface of the muscle?
Where should the reference electrode be placed?
Electrical safety concerns
How should the EMG signal be processed?
Applications of the EMG signal
Perceptual-Motor Workspace
Daniel J. Weeks, Romeo Chua, &Tracey Kerr
Human Factors Lab
Laboratory for Perceptual-Motor Dynamics
School of Kinesiology, Simon Fraser University,
Burnaby, British Columbia
paper available at (http://fas.sfu.ca/kin/research/perceptual-motor.html)
[Editors note: Two 1997 papers from the Human Interface Technology Laboratory, University of Washington - complete index at http://www.hitl.washington.edu/publications/index.html]
New Interface Metaphors for Complex Information Space Visualization: an ECG Monitor Object Prototype
Stan Kaufman, Ivan Poupyrev, Edward Miller, Mark Billinghurst, Peter Oppenheimer, Suzanne Weghorst
Division of Cardiology, VA Medical Center and U. of Washington
Human Interface Technology Laboratory, U. of Washington
Box 352-142, Seattle, WA 98195
(Full paper at http://weber.u.washington.edu/~tinman/MMVR5/warm.html)
Shared Space: An Augmented Reality Approach for Computer Supported Collaborative Work.
M. Billinghurst, S. Weghorst, T Furness III
Human Interface Technology Laboratory
University of Washington
{grof, weghorst, tfurness}@hitl.washington.edu
(full paper at http://www.hitl.washington.edu/publications/r-97-1/)
There are still a few copies of previous Conference Proceedings available for sale at rock bottom prices. These will be of particular interest to new members and students. All prices include postage (within Australia).
Designing a Better World (2 volumes) Sydney 1988 $ 5
Ergonomics, Technology, Productivity Canberra 1989 $ 5
Ergonomics & Human Environments Brisbane 1991 $10
Unlocking Potential for the Future Melbourne 1992 $10
Ergonomics in a Changing World Perth 1993 $10
The Fundamental Design Science Sydney 1994 $10
Widening Our Horizons Adelaide 1995 $15
Enhancing Human Performance Canberra 1996 $30
Also there are a very small number of copies of Mike Stevenson's "Readings
in RSI- The ergonomics approach to repetition strain injuries" at the give
away price of $9.
We also have a limited number of pre-1988 Conference Proceedings available.
If you are interested please give the office a call to see what is available.
Please make cheques payable to ESA and forward to:
ESA
Canberra Business Centre
Bradfield Street
DOWNER ACT 2602
Phone: (06) 242 1951 Fax: (06) 241 2554 Email: esa@ozemail.com.au
Lynn Parry
Products & Services
1997
November 25-27. ESA National Conference Gold Coast (see elsewhere in this issue).
1998
The preferable form of submission is via email, either in the body of a message, or as an attachment. Files may also be mailed on floppy, (or Zip disc if very large). Virtually any format of files can be accommodated. Otherwise contributions should be printed in a large (14 pt preferred) non-serif font (such as Helvetica) and faxed to 07 33793545. Printed pages of similar specification may also be sent by post. Handwritten submissions will only be accepted in exceptional circumstances.
Submission deadline for each issue is 10th of the month, ie, April 10, June 10, August 10, October 10, December 10, February 10.
Intending contributors are invited to contact the editor to discuss potential submissions.
All enquiries or feedback should be addressed to the editor, Robin Burgess-Limerick PhD.
Email: robin@hms.uq.edu.au
These pages are hosted by the Department of Human Movement Studies, The University of Queensland, AUSTRALIA