When people are anxious they release a chemical signal that’s detectable on a subconscious level by those close to them. That’s the implication of a new study that collected sweat from people as they completed a high-rope obstacle course, and then tested the effect of that sweat on study participants as they played a gambling game.
Katrin Haegler‘s team placed the sweat samples inside odourless tea bags which were attached with an elastic band to the underside of the gambling participants’ noses. For comparison, the participants were also exposed to sweat collected from non-anxious riders of an exercise bike.
When exposed to the anxious sweat, the participants took longer to decide over, but were more likely to bet on, the highest risk scenarios – wagering that the next playing card in a pair would be higher than a 9 (where 10 was as high as the cards went) or lower than a 2 (where 1 was the lowest). In other words, the detection of another person’s anxiety made them more willing to take risks. Quite why this should be remains unclear. However, the idea that humans can detect the anxiety of others via chemical signals is not new. For example, a 2009 study showed that sweat collected from an anxious person, compared with from an exerciser, triggered extra activity in a range of emotion-related brain areas.
The participants in the present study rated the anxiety-laced sweat and anxiety-free sweat as equally unpleasant and intense, suggesting, consistent with past research, that they couldn’t consciously tell the difference between the two. So the effect of anxiety-laced sweat on risk-taking seems to have been a non-conscious influence.
‘Although it is not fully understood if perception of emotional chemical signals in humans may have the ability to alert conspecifics about possible danger [as happens with some animals],’ the researchers said, ‘our findings suggest that anxiety in humans can be communicated through chemical senses.’
Haegler K, Zernecke R, Kleemann AM, Albrecht J, Pollatos O, Brückmann H, and Wiesmann M (2010). No fear no risk! Human risk behavior is affected by chemosensory anxiety signals. Neuropsychologia, 48 (13), 3901-8 PMID: 20875438