Today, I am a self-proclaimed dog enthusiast—I love ‘em all. But when I was a child, I was deathly afraid of them after one stole my snickerdoodle. Sure, it’s comical now, but back then it was the ultimate betrayal and I vowed to never trust another dog again. Instead of greeting them with excited coos, I would hide behind my mom’s legs, whilst attempting to convince myself I wasn’t afraid… because I knew that they could smell my fear. This, of course, only enhanced my anxiety, every dog’s interest in me, and my subsequent fear of them. I mean they had a one-up on me, what was I supposed to do?
If I could talk to my 10-year-old self, I’d tell her just how silly she was really being. While it’s certainly understandable to develop a disliking after cookies are stolen, my initial belief that a dog’s ability to smell fear was some kind of superpower was inherently wrong—little did I know that I possessed the same “superpower.” While our sense of smell is not our primary sense (like it is with dogs and other mammals), humans do subconsciously read and react to certain odors, which communicate happiness, fear, and aggression… but we might not all react the same.
Being that smell is a form of social communication, researchers from Weizmann Institute of Science began wondering how it might vary in those with social disorders like autism. This initial pondering led them to conduct their study “Altered responses to social chemosignals in autism spectrum disorder,” which reveals that individuals on the autism spectrum have opposite reactions to odors of the human body. These findings give us a better look at and understanding of autism, such as its potential developmental malfunctions.
To reach these findings, the research team held a series of experiments with volunteers on the high functioning end of the autism spectrum. First, they tested the abilities of both autistic and control participants to identify easy smells, such as sweat—there appeared to be no difference between the two groups. Then, all of the participants were exposed to one of two scents: either the “smell of fear” (which was sweat collected from people in skydiving classes), or a control odor—which was sweat from the same people, but only after exercising.
This is where the researchers began to observe significant differences. Neither group reported sensing variations between the smells, but their bodies certainly did: Those in the control group exposed to the “smell of fear” showed significant and measurable increases in the fear response, while those who smelled the control odor did not. And the very opposite was observed in the autistic group—those who were exposed to the “smell of fear” showed significant decreases in the fear response, while those who smelled the control odor showed increases in the fear response.
The research team continued experimenting, this time introducing robotic mannequins into the equation. These mannequins were designed to emit different odors through their nostrils, while giving participants different tasks to complete, which would allow the researchers to analyze the level of trust the individuals had in the mannequins. Again, the team observed differences in the control and the autistic group: the control group showed less trust in the mannequins when they emitted fear-induced odors, while the autistic group showed more trust in the midst of fear-induced odors.
Further experimentation explored whether other social odors impact those with autism differently and led to a better understanding of this variation in autistic individuals: it’s not that they’re unable to read olfactory social cues, but they misunderstand them. The researchers believe that this may signify a stronger connection between our sense of smell and early stages of development, although further research is needed.
Weizmann Institute of Science (2017, November 27). Autism and the Smell of Fear. NeuroscienceNews. Retrieved November 27, 2017 from http://neurosciencenews.com/olfaction-fear-autism-8039/
Endevelt-Shapira, Y., Perl, O., Ravia, A., Amir, D., Eisen, A., Bezalel, V., Rozenkrants, L., Mishor, E., Pinchover, L., Soroka, T., Honigstein, D., & Sobel, N. (2017, November 27). Altered responses to social chemosignals in autism spectrum disorder. Nature Neuroscience. Retrieved November 28, 2017 from https://www.nature.com/articles/s41593-017-0024-x