Full atricle – neurophilosophy
Category: Neuroscience • Vision, Posted on: November 6, 2009 12:50 PM, by Mo
A novel temporal illusion, in which the cause of an event is perceived to occur after the event itself, provides some insight into the brain mechanisms underlying conscious perception. The illusion, described in the journal Current Biology by a team of researchers from France, suggests that the unconscious representation of a visual object is processed for around one tenth of a second before it enters conscious awareness.
Chien-Te Wu and his colleagues at the Brain and Cognition Research Centre in Toulouse used a visual phenomenon called motion-induced blindness, in which a constantly rotating background causes prominent and motionless visual stimuli to disappear and reappear, as demonstrated in the video below. Fixate on the flashing green spot in the centre, and you’ll notice that the surrounding yellow spots begin to disappear and reappear after about ten seconds. Then replay the clip and focus on any of the yellow spots; you’ll see that it is a visual disappearance illusion. Exactly how it works is unclear; according to one hypothesis it is due to the properties of neurons in area V1 of the visual cortex.
Motion Induced Blindness – The most amazing videos are a click away
The researchers first used a variation of these stimuli to test the occurence and duration of the motion-induced blindness effect. In these pre-test trials, seven participants were presented with a static yellow ring on a rotating background, and asked to report when the ring disappeared from and reappeared to conscious awareness, by respectively pressing and releasing a button. read more…