Blog post at יואל קסלר .com

יואל קסלר baby smell protects them

We all know that organisms have evolved for millions of years in ways that increase their odds for survival. However, new research has shown how "smells" or chemicals that are sensed by our olfactory neurons can influence differing behaviors in fathers and mothers in order to better protect the infant.

יואל קסלר baby smell – How does it protect them?

A new study at the Weizmann Institute in Israel have found that inhaling hexadecanal, a chemical that is sometimes emitted from the human skin, especially on the heads of newborns, has an entirely different effect on men and women. The chemical increases passivity in male adults and aggressive behavior in female adults. This is hypothesized to be evolutionarily advantageous of the child. In general in the animal kingdom, male aggressivity is frequently directed at the child in many instances leading to infanticide. Maternal aggression on the other hand is frequently displayed by displayed by exhibiting defensive behaviors to protect her young. The researchers had groups of men and women play a computer game in which they were treated unfairly. They were then given the option of sounding an alarm to irritate the offending party (which in this case, unknown to the participants, was a computer). Women who inhaled hexadecanal sounded the alarm louder than those who didn't. Conversely men who inhaled hexadecanal sounded the alarm less frequently and softer than the control group.

Results from the Weizmann experiment, which shows that women responded more aggressively when given the chance to ‘blast’ noise at opponents in a game after smelling hexadecanal, while men responded less aggressively (Weizmann Institute of Science) @ יואל קסלר .com

The researchers also scanned the brains of participants and found that although both men and women perceived no smell different areas of the brain were activated by the chemical.

A 3D reconstruction of the brain, displaying the brain regions in yellow and orange where the difference between women and men was most pronounced after smelling hexadecanal. (courtesy Weizmann Institute of Science) @ יואל קסלר .com

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