Sometimes we think of emotions as completely separate from the more “objective” parts of the mind. You might believe that emotion can sometimes cloud your judgment, but it certainly can’t affect your vision system. Or can it?
Take a look at the following image. It’s my attempt to use Photoshop to make a Gabor patch — a means of testing vision.
Gabor patches are useful because researchers can systematically vary their contrast and determine the limits of the visual system. For example, try this quick movie. The screen will remain blank for a second, then quickly flash four Gabor patches. Can you tell if one of them is tilted?
You can give your response in the poll below the fold.
How were you feeling when you viewed the movie? Happy? Sad? Afraid? A team led by Elizabeth Phelps has found that performance on this task is actually affected by emotion. They showed 14 observers hundreds of similar movies, but with a twist. Fifty milliseconds before the Gabor patches were flashed onscreen, one of eleven different faces was briefly displayed. The face displayed either a neutral or fearful expression. When observers saw a fearful face, they were better at noticing when one of the Gabor patches was tilted. Here’s a chart of accuracy for varying levels of contrast.
At lower contrast levels, the patches are much more difficult to see, so the task became more difficult. But at nearly every level of contrast, accuracy was higher when participants saw the fearful face. An emotion — fear — affects viewers’ ability to see.
But why? Phelps’s team speculates that because seeing a fearful expression causes a response in the amygdala, the amygdala may in turn activate the areas of the visual cortex responsible for attention, thus actually improving visual performance.
P.S.: I’ll give the correct response to the poll question after we’ve had 30 or so responses.
Phelps, E.A., Ling, S., & Carrasco, M. (2006). Emotion facilitates perception and potentiates the perceptual benefits of attention. Psychological Science, 17(4), 292-298.