A chemical emitted from our skin, feces, and breath with no detectable smell appears to influence people's behavior, making men calmer but triggers women to be aggressive, according to a recent study.

Unraveling the Role of Body Odor in Behavior

Underarm
(Photo: Wikimedia Commons/Steve Shook)

Researchers analyzed the effects of a chemical compound known as hexadecanal (HEX) on the human brain. Unlike other compounds that contribute to body odor, HEX has no discernible smell but can be sensed by all mammals. Although scientists are not sure when or under what conditions is this chemical compound excreted in people and other mammals, it is clear that humans are, in a way, communicating with each other subconsciously through the odor of their body explains Eva Mishor, lead author and a researcher at the Weizmann Institute of Science, Israel, reports NewScientist.

Mishor explains that humans can smell each other. Whether it's their child, romantic partner, or strangers. The study published in the journal Science Advances, titled "Sniffing the human body volatile hexadecanal blocks aggression in men but triggers aggression in women," aims to give more depth to the notions that we humans can communicate via chemical volatiles that we emit and get information based off of them.

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Body Odor: Understanding its Role in Behavior Changes in Men and Women

Researchers found that the HEX compound decreased connectivity in parts of the human brain that are charged with regulating social decision-making for women, including their decision to become more aggressive. However, it increases connectivity among men.

HEX is also found abundantly on the heads of newly born babies. Researchers suggest that as an evolutionary tool years ago, HEX on newborn babies' heads suppressed the aggression in men to make them less susceptible to harming fragile infants.

A vital aspect of the process in a brain region on both the left and right side is known as the angular gyrus, which authors describe as a social hub of the brain. It is already known to play a vital role in language and number processing, reasoning, and memory. However, it is activated under exposure to the compound HEx in both men and women when they are provoked.

Mishor suggests an evolutionary explanation on why the HEX compound affects the sexes differently. According to the author, male aggression often translates to aggression toward newly born babies. Where infanticide is a common phenomenon in the animal kingdom. On the other hand, female aggression translates to defending the newborns.

When it comes to the evolutionary benefit of HEX, researchers aren't 100% sure. They suspect that the compound concentration varies in different situations, depending on whether aggression is needed to respond to external stimuli, reports DailyMail.

Researchers recruited 127 participants from a 'double-blind' test for the study where neither the participants nor experimenters knew who was receiving a set of treatments. The study utilized two validating scientific methods in gauging aggressive behavior in humans known as the 'aggression paradigms.'

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