The School of Psychology proudly presents:
The Psychonomics Seminar Series 2008
"Navigating the depths of ignorance guided by the shining star of empiricism"
This Friday, at 3pm in room 302, Derek Arnold will present a talk titled "Timing Perception, Cortical Processing and Free-Will"
As of yet, it is unclear how we determine relative perceived timing. One controversial suggestion is that
timing perception might be related to when analyses are completed in the cortex of the human brain. An alternate proposal suggests that timing perception is instead related to when such analyses commence. Accordingly, timing illusions should not occur owing to cortical analyses, but could occur if there were differential delays between signals reaching the cortex. Resolution of this controversy therefore required that the contributions of cortical processing be isolated from that of subcortical activity. We did this by using binocular disparity changes, which are known to be detected via analyses that originate in cortex. We found that observers required longer stimulus exposures to detect small, relative to larger, disparity changes, and that observers misperceived smaller disparity changes as being perceptually delayed. Interestingly, disparity magnitude influenced perceived timing more dramatically than it did stimulus change detection. Our data therefore suggest that perceived timing is both influenced by cortical activity and shaped by sensory analyses subsequent to those that are minimally necessary for stimulus change perception. These results have surprising implications for a persistent debate concerning the existence of free-will.
Derek Arnold was raised by a pack of wild dogs in the Yalwal state forest, west of Nowra NSW. For those of you who have been wondering, this goes some way toward explaining the howling often heard on the 4th floor of the McEllwain building on Friday afternoons. He