Science & Technology - Posted by Carol Clark-Emory on Friday, October 26, 2012 11:18 - 0 Comments
Fear makes scary stuff appear to loom
EMORY (US) — Fear can make threatening objects appear more looming than they actually are, a recent study finds.
“Our results show that emotion and perception are not fully dissociable in the mind,” says Stella Lourenco, assistant professor of psychology at Emory University. “Fear can alter even basic aspects of how we perceive the world around us. This has clear implications for understanding clinical phobias.”
People generally have a well-developed sense for when objects heading towards them will make contact, including a split-second cushion for dodging or blocking the object, if necessary.
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For the study, published in Current Biology, the researchers set up an experiment to test the effect of fear on the accuracy of that skill.
Participants made time-to-collision judgments of images on a computer screen. The images expanded in size over one second before disappearing, to simulate “looming,” an optical pattern used instinctively to judge collision time. They were instructed to gauge when each of the visual stimuli on the computer screen would have collided with them by pressing a button.
The participants tended to underestimate the collision time for images of threatening objects, such as a snake or spider, as compared to non-threatening images, such as a rabbit or butterfly.
The results challenge the traditional view of looming, as a purely optical cue to object approach.
“We’re showing that what the object is affects how we perceive looming. If we’re afraid of something, we perceive it as making contact sooner,” says co-author Matthew Longo, a psychologist at Birkbeck, University of London.
“Even more striking, it is possible to predict how much a participant will underestimate the collision time of an object by assessing the amount of fear they have for that object,” Lourenco says.
“The more fearful someone reported feeling of spiders, for example, the more they underestimated time-to-collision for a looming spider. That makes adaptive sense: If an object is dangerous, it’s better to swerve a half-second too soon than a half-second too late.”
It’s unclear whether fear of an object makes the object appear to travel faster, or whether that fear makes the viewer expand their sense of personal space, which is generally about an arm’s length away.
“We’d like to distinguish between these two possibilities in future research,” Lourenco says. “Doing so will allow us to shed insight on the mechanics of basic aspects of spatial perception and the mechanisms underlying particular phobias.”
Source: Emory University