Wen Zhou's and Denise Chen's new finding shows that this overlap extends to behavioural performance.
Forty-four female university students were twice tasked with smelling three t-shirts and picking out the one that belonged to their room-mate. The t-shirts had been carefully prepared - worn overnight for an average of eight hours, after the owner had used scent-free toiletries for the previous two days.
Based on their performance, the students were arranged in three groups: 21 of them failed both times to pick out the correct t-shirt; 10 of them picked the correct t-shirt once; and 13 of them picked the correct t-shirt both times. The key finding was that the students who both times identified their room-mate's t-shirt by its smell also tended to excel at a test of identifying facial emotional expressions, and at a test of empathy in which they had to say how someone would feel in a range of different situations.
The students' confidence in their choices of t-shirt showed no association with their actual performance, thus suggesting that the ability to identify a room-mate's smell appeared to be implicit.
Further analysis showed that it was specifically the students' skill at using smell for "social" purposes that was linked with empathy. General keenness of smell and the ability to name a range of different odours were not linked to empathy in any way. The intensity and pleasantness of the t-shirt smells were also unrelated to the students' ability to identify their room-mates.
"To our knowledge, this study provides the first empirical evidence of the behavioural connection between a sensory system and emotional processing," the researchers said. "The behavioural findings reported here suggest that sociochemical signals may tap into a broader network of social cognition and emotion, and that similar underlying mechanisms may regulate sociochemosensory and emotional competencies."
Zhou W, & Chen D (2009). Sociochemosensory and emotional functions: behavioral evidence for shared mechanisms. Psychological science : a journal of the American Psychological Society / APS, 20 (9), 1118-24 PMID: 19686296
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.