Scientists revealed the reason behind your smile. Not all smiles express kindness and joy, Sometimes they can be complete mean according to a new study by US psychologists.
The study shows that human bodies tend to react differently depending on the message a smile is meant to send.
Research led by Jared Martin, a psychology graduate student at the University of Wisconsin-Madison, shows that smiles meant to send a message have an association with a physical reaction, a molecular rearrangement to produce a physical change.
On the other hand, smiles meant to strengthen behavior that occurs to physically buffer recipients against stress.
Researchers built three major types of smiles as leverage — meant to convey dominance –, reward — the sort of relying on, toothy smile you would give someone to let them know they are making you happy, and affiliation– which communicates a bond and shows you are not a threat.
For the study, the team of researchers included male college students in the study and gave them a series of short, impromptu speaking assignments. They tracked them over a webcam by a fellow student. The team measured heart rates and levels of cortisol which is a hormone associated with stress.
Co-author Paula Niedenthal said, “If they received dominance smiles, which they would decode as negative and critical, they felt more stress, and their cortisol went up and stayed up longer after their speech.”
Niedenthal also added, “If they received reward smiles, they reacted to that as approval, and it kept them from feeling as much stress and producing as much cortisol.”
The team found stronger physiological reactions to the different smiles among participants with high heart-rate variability.
Scientists revealed the reason behind your smile