Scientific experiments by a University of Queensland researcher have shown that our own brain activity can influence our sense of timing.
Work by Dr Derek Arnold of the UQ School of Psychology goes against a widely held belief that activity in the cortex of the human brain does not influence how we perceive time.
Dr Arnold has been awarded $60,000 as one of the 2007 winners of the UQ Foundation Research Excellence Awards and Awards for Excellence in Research Higher Degree Supervision, announced at Brisbane Customs House on September 18.
Now in their ninth year, the UQ Foundation Research Excellence Awards, worth $505,000 in 2007, recognise outstanding performance and leadership potential, and form part of UQ Research Week (September 17–21).
Dr Arnold’s project will build on his recent work and will have substantial implications for understanding the mechanisms involved in time perception.
“Clarifying the mechanisms involved in normal time perception will obviously help in understanding situations where those mechanisms fail,” he said.
“So, in addition to the considerable theoretical significance, the results of this project may have implications for our understanding of disorders associated with impaired time perception, such as autism, dyslexia and schizophrenia.”
Dr Arnold’s recent work has examined sensory changes that can only be detected because of activity in the cortex of the human brain.
He has found that large changes can be detected more rapidly than smaller changes. He also found that large changes seemed to occur earlier than did smaller changes.
“The size of the change had a greater impact on timing than it did on the ability to detect the change,” he said.
“So, it seems that perceived timing is more closely related to when observers become confident of change detection, rather than with the point at which changes can actually first be detected.
“These results have some surprising implications. The most obvious is that our sense of timing is shaped by activity in the cortex of the human brain. The other concerns the existence of free will.
“It is believed by many scientists and philosophers that our actions are instigated by unconscious processes over which we have no control.
“However, our results suggest that we are responsible for our own actions.”
Dr Arnold said a timing experiment had previously been used to question the existence of free will.
“In the 1980s, a US-based physiologist, Benjamin Libet, had observers instigate a movement at a random time of their own choosing while he recorded activity from their brains,” he said.
“The observers reported when they had decided to instigate movement.
“Surprisingly, brain activity related to the instigation of movement could be detected before observers reported that they had decided to move.
“Scientists and philosophers have used these results to question the existence of free will, the idea being that our decisions are just an explanation we use to make sense of actions that have already been instigated by unconscious processes over which we have no control.
“However, this idea is based on the premise that observers have an accurate sense of timing. Our more recent results suggest that this is unlikely.”
Dr Arnold said his research data suggested that observers were conservative – that timing judgments reflected when observers became confident of detection, but not of when changes could first be detected.
“The apparent delay of decisions to instigate movement, relative to the brain activity involved in implementing that movement, probably involved the same type of inaccurate and conservative sense of timing,” he said.
“Accordingly, we would be responsible for our own decisions – we just wouldn’t have a very accurate sense of when we made them.”
Dr Arnold, who was awarded his PhD in the field of visual perception by Macquarie University in Sydney in 2003, worked at University College London before joining UQ 18 months ago.
He said he was attracted to UQ by the exciting opportunity to work with internationally recognised sensory neuroscience researchers, particularly in the School of Psychology, and at the Queensland Brain Institute.
Media: Dr Derek Arnold (telephone 07 3365 6203, email: darnold@psy.uq.edu.au) or Jan King at UQ Communications (07 3365 1120).
