Perception’s vulnerability to emotion

Our brains can be blinded by emotions, says Vanderbilt University psychologist David Zald.

Zald and his colleagues trained twenty-one volunteers to spot a neutral target image — like a picture of a tree or a typical building — out of a series of other images flying by at 10 pictures per second. They asked the subjects to press a key when they spotted their image and indicate whether that image was rotated to the left or the right. He says the volunteers could do this correctly 90 percent of the time. But as he and his team reported in Psychonomic Bulletin and Review, if a gory or erotic image was presented before the target image the participants were far more likely to miss the target.

“When an emotional picture appears, it seems to short circuit that processing in the brain that will then help you construct a visual conscious perception,” says co-author Steven Most, a psychologist at Yale University.

According to the Discover article from which I’ve excepted, Zald believes that emotionally charged information can literally block the brain from perceiving subsequent information.

Another clue to the malleability of perception that I blogged about yesterday.

;-)

More on the malleability of perception

A Cornell University study examines the relationship between what we believe about people and our memory of events involving them.

To conduct the study, David Pizarro, assistant professor of psychology at Cornell, and three colleagues

gave 283 college students a story about a man who walked out on a restaurant bill, including what the man ate and drank and the amount of his bill. Half the participants read that the man walked out on the bill because he “was a jerk who liked to steal,” and half read that the man left without paying because he received an emergency phone call.

“One week later the people who were told he was a jerk remembered a higher bill — from 10 to 25 percent more than the bill actually was. Those who were told he had an emergency phone call remembered a slightly lower-than-actual bill,” said Pizarro.

The researchers appear focused on how these distortions may affect civic institutions (e.g. eyewitness testimony during criminal trials); they also characterize the distortions as stemming from observers’ ethical judgments. In Pizarro’s words: “[O]ur study shows that morally blaming a person can distort memory for the severity of his or her crime or misbehavior.”

But it seems to me that something broader is at work, here. It’s not morals, but motivation. When we witness events involving other people, and string those events together as a narrative, the narrative is shaped by our understanding of the players’ motivations.

At some point, we also “shade in” or heighten certain details within our memory of events in order to capture or express our understanding of it more accurately (as opposed to cataloguing what actually happened).

Kinda like writing fiction ;-)

The full study will be published in a forthcoming issue of the Memory and Cognition.

(Incidentally, the Cornell article I’ve quoted here implies that every single person in the study misremembered the bill. Hmmmmm. I suppose that’s possible . . .)