Women who were exposed to chemicals from fear-induced sweat performed more accurately on word-association tasks than did women exposed to chemicals from other types of sweat or no sweat at all. The study was published this month in the journal Chemical Senses.

"It is well-documented in the research literature that animals experiencing stress and fear produce chemical warning signals that can lead to behavioral, endocrinological and immunological changes in their fellow animals of the same species, but we wanted to see if this applies to humans as well," said principal investigator Denise Chen, assistant professor of psychology at Rice.

For the study, Chen collected samples of sweat from research volunteers who kept gauze pads in their armpits while they watched videos of horror movies and nonthreatening documentaries. The sweat samples were then stored in a freezer until needed for the study.

Next, Chen had 75 female students between the ages of 18 and 22 respond to 320 pairs of words that flashed for three seconds each on a computer screen. For each pair, the participants had to press a key to indicate whether the words were associated with each other (for example, arms and legs) or not (arms and wind). Some of the words were associated with threatening or fear-related topics, like weapons.

Each participant had a piece of gauze attached above their lips so that they were exposed to either chemicals from sweat or none at all during the tests. Chen compared how the chemicals from sweat impacted the speed and accuracy of participants' results on the word-association tests.

When processing meaningfully related word pairs, the participants exposed to the fear chemicals were 85 percent accurate, and those in either the neutral sweat or the control (no-sweat) condition were 80 percent accurate. "The subje
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Contact: B.J. Almond
balmond@rice.edu
713-348-6770
Rice University
31-Mar-2006