Eagleman, David
Coauthors(s): Terrence J. Sejnowski, CNL, Salk
The Salk Institute
Computational Neuroscience
10010 N. Torrey Pines Rd. La Jolla, CA 92037
www.cnl.salk.edu/~eagleman

The timing of perception: how far in the past do we live, and why?

While it is clear that different features of stimuli are processed in different areas of the brain, it is underappreciated that information is processed in these areas at widely varying times. Yet somehow perception retains very exact temporal information about outside events. This leaves us with the surprising result that physiologically-measured latency differences do not generally translate into perceptual time differences. How the widely varying stimulus-evoked latencies in the neural tissue can be temporally registered to yield the coherence of perception, is what we define as the temporal binding problem. Concentrating on the visual system, we employ physiological and psychophysical data to argue that the features of awareness necessitate a window of delay and postdiction, the act of retrospectively attributing an interpretation to events in the past. We will illustrate this framework by demonstrating some novel predictions and results regarding the line-motion illusion. We argue that postdiction is the only framework that provides a unified explanation for many psychophysical phenomenon.