'Mind's eye' impacts our visual perception

Washington, July 4 : Seeing with the "mind's eye" i.e. mental imagery (imagination), can actually influence the way you see the world, says a new research.

The latest study from Vanderbilt University was published online June 26 by the journal Current Biology in a paper titled, "The Functional Impact of Mental Imagery on Conscious Perception." "We found that imagery leads to a short-term memory trace that can bias future perception," says Joel Pearson, research associate in the Vanderbilt Department of Psychology and lead author of the study.

"This is the first research to definitively show that imagining something changes vision both while you are imagining it and later on," Pearson added. The researchers said: "These findings are important because they suggest a potential mechanism by which top-down expectations or recollections of previous experiences might shape perception itself." To test how imagery affects perception, the research team had subjects imagine simple patterns of vertical or horizontal stripes, which are strongly represented in the primary visual areas of the brain.

They then presented a green horizontal grated pattern to one eye and a red vertical grated pattern to the other to induce what is called binocular rivalry. During binocular rivalry, an individual will often alternately perceive each stimulus, with the images appearing to switch back and forth before their eyes.

The subjects generally reported they had seen the image they had been imagining, proving the researcher's hypothesis that imagery would influence the binocular rivalry battle. Additional experiments found that the effect of imagery on perception was approximately the same as showing the research subject a faint representation of one of the patterns between trials.

Stronger shifts in perception were found if subjects either viewed or imagined a particular pattern for longer periods of time. They found that both imagery and perception can lead to a build-up of a "perceptual trace" that influences subsequent perception.

ANI