Activating something called the behavioral immune system puts a damper on dating, new research shows.
About a decade ago, evolutionary psychologists suggested that humans have evolved a first line of defense against disease: this behavioral immune system or BIS.
The theory is that perceiving, rightly or wrongly, the threat of disease unconsciously activates this system.
Although we cannot see microorganisms with the naked eye, we are nevertheless able to identify cues – such as coughs, unpleasant smells, or skin lesions – that hint at the possible presence of pathogens, whether or not these are actually present or represent real health threats.
Scientists have suggested that the activation of the BIS leads to prejudiced and avoidant attitudes and behavior towards those who display superficial cues connoting disease.
But how does this affect our dating lives, where two competing needs are pitted against one another – i.e., the potential benefits of connecting and finding a mate versus the need to protect oneself from disease?
McGill University scientists set out to find out, by looking at the activation of the BIS in young, single, heterosexual Montrealers in both real speed-dating events and in experimental online dating.
The results were convincing. And not very happy.
"We found that when the behavioral immune system was activated it seemed to put the brakes on our drive to connect with our peers socially," says first author of the study Natsumi Sawada, who holds a PhD in psychology from McGill University.
"We hadn't expected this to be the case in real life situations like dating where people are generally so motivated to connect. The results suggest that beyond how we consciously or unconsciously think and feel about each other there are additional factors that we may not be consciously aware of, such as a fear of disease that may influence how we connect with others."
This video explains how the experiments worked:
The findings appear in the Personality and Social Psychology Bulletin.