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.
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When I was in the Army we all acknowledged that we could see and hear better when we we scared. We assumed it was an evolutionary trait for survival, ourselves, related to adrenaline.
That makes perfect sense to me. While I have absolutely no knowledge of anything related to psychology, this reminds me of the last CUSEC, where Kathy Sierra, a writer of technical books, gave a keynote speech (which can now be downloaded and listened to) where she discussed how to keep people focused and learning even if the subject is dry.
One of the things she says is that humans are geared towards recognizing faces. Whenever we see a face our brains begin trying to analyze it. If it's a fearful face, we're woken up as our primal instincts kick in and we wonder whether we're supposed to be scared, too. Therefore, she concludes, using pictures of faces - with silly or excited expressions, for example - help keep you focused while reading one of her "Head First" books.
Here's the promised update: as you might guess, our respondents are accurate. The patch in the lower right was tilted. But to get a real sense of our collective vision, we'd need to repeat the experiment with different levels of contrast.
I'm trying to figure out how this would apply to horror movies. If fear improves visual performance, then why did people "see" the knife plunge into Janet Leigh's body in the shower scene in PSYCHO, and why didn't more people see the subliminal death masks in THE EXORCIST (in the scenes where Father Damian dreams of his dead mother coming up out of the subway and at the end during the exorcism)? Why did people remember seeing the demon baby in ROSEMARY'S BABY (no such scene was filmed), or remember the original TEXAS CHAINSAW MASSACRE as being much more gory rhan it really was? I suppose in at least some of these cases there's something much more complex going on than what was done in the study. Anyone have any thoughts on this matter?
David, good points.
I think your hunch that something much more complex is going on is correct. For one thing, we're talking more about memory than visual ability. I'd be interested to see the results of a more immediate, in-movie test.
Also, movie music has a lot to do with what people think they see. Take a look at this post for more.
I can't get at the original source from here -- but when I look at that psychometric function, it looks like the criterion was shifted, that means they didn't see more but were more ready to accept an "outlier". But probably they did a proper symmetric forced choice or a d' analysis to control for that.
sorry for double post -- one should read before sending... [I could claim "no native speaker", but that's lame :-).] In my above text, the "theys" referred to different things. Retry:
... from that psychometric function, it looks like the participants' criterion was shifted, that means they didn't see _more_ but were more ready to accept an "outlier". But probably the experimenters did a proper symmetric forced choice or a d' analysis to control for that.
I cannot attest or speculate as to how neurons react but as a result of life experience I am aware that anxiety can certainly cause us to become cognitively sharper and more aware of our surroundings. I would guess that a fearful expression might result in a small amount of anxiety which could result in improved visual awareness.
Though this seems to suggest that fear or anxiety may encourage an increase in visual acuity perhaps the natural response to such emotions is to become more sensitive to stimuli. After all, some claim to "hear" things in the night when they are frightened, but often times the sounds that catch ones attention are amplifications of something benign. What influence does imagination have on human reactions to fear?