
Have you ever met someone you instantly liked, or at other times, someone who you knew immediately that you did not want to be friends with, although you did not know why?
In Malcolm Gladwell’s best selling book, Blink, he explores this phenomenon highlighting the idea of an “unconscious” part of the brain that enables us to process information spontaneously, when, for example, meeting someone for the first time, interviewing someone for a job, or faced with making a decision quickly under stress.
The University of Maryland School of Medicine (UMSOM) attempted to quantify a biological basis behind this instantaneous compatibility reaction identifying variations of an enzyme found in a part of the brain that regulates mood and motivation. In the mice being studied, that enzyme seems to control which mice want to socially interact with other mice — with the genetically similar mice preferring each other.

Michy Kelly, PhD, Associate Professor of Anatomy and Neurobiology, who led the study, says their findings may indicate that similar factors could contribute to the social choices people make. Understanding what factors drive these social preferences may help us to better recognise what goes awry in diseases associated with social withdrawal, such as schizophrenia or autism, so that better therapies can be developed.
“We imagine that this is only the first among many biomarkers of compatibility in the brain that may control social preferences,” said Dr. Kelly. “Imagine the possibilities of truly understanding the factors behind human compatibility. You could better match relationships to reduce heartache and divorce rates, or better match patients and doctors to advance the quality of healthcare, as studies have shown compatibility can improve health outcomes.”