Mirror sniffing: humans mimic olfactory sampling behavior

Ample evidence suggests that social chemosignaling plays a significant role in human behavior. Processing of odors and chemosignals depends on sniffing. Given this, we hypothesized that humans may have evolved an automatic mechanism driving sniffs in response to conspecific sniffing. To test this, we measured sniffing behavior of human subjects watching the movie Perfume, which contains many olfactory sniffing events. Despite the total absence of odor, observers sniffed when characters in the movie sniffed. Moreover, this effect was most pronounced in scenes where subjects heard the sniff but did not see the sniffed-at object. We liken this response to the orienting towards conspecific gaze in vision and argue that its robustness further highlights the significance of olfactory information processing in human behavior.