Snakes on a Brain

August 1, 2009

Virtual reality might be too real, at least when it comes to our fears. Researchers in the department of psychology and neuroscience are looking into the kinds of phobic memories formed in two different environments: a plain lab space and in the Duke Immersive Virtual Environment (DiVE), a six-sided virtual-reality theater on campus.

First, Nicole Huff, a postdoctoral researcher, and her adviser, Kevin LaBar, an associate professor of psychology and neuroscience, showed two-dimensional images of open-jawed rattlesnakes or lurking tarantulas to subjects seated in laboratory cubicles. The images were coupled with a mild electrical shock to the wrist.

Those experiences created a sense of fear, measured by extra sweat on the subjects' skin. But a day later, when they returned and were shown the images again, this time without any shocking, most of their fear did not resurface.

Subjects tested in the DiVE were confronted with three-dimensional spiders and snakes accompanied by scuttling sounds or rattling and the same mild shock. Overwhelmingly, when they returned for a second day, this time without the shock, the subjects still expressed the same strong fears as before. Immersive experiences "may engage brains more intensely than a normal laboratory study," Huff says.

The experiments are intended to test how, and for how long, the human brain stores memories of a disturbing experience in a particular place or context. In DiVE simulations in which the subject's encounter with the snake or spider took place outside, more fearful memories persisted than in the cases of subjects who "saw" a snake or spider inside a kitchen or living room.