A new study published in the Proceedings of the National Academy of Sciences suggests that brotherly love and xenophobia may be two sides of the same coin. Oxytocin, a hormone often sweetly referred to as a “love drug” or a “cuddle chemical,” may also be responsible for prejudice against outsiders.
Carsten K. W. De Dreu, the Dutch social psychologist behind the study, hypothesized that the inclination to take care of those who are familiar was associated with the inclination not to take care of those who were unfamiliar. He suspected that the same hormone that enables us to love our neighbor also makes us kind of suspicious of that guy who lives down the block.
De Dreu embarked on his research after pessimistically reasoning that a brotherly love hormone must have a caveat to be evolutionarily viable. If we were only cuddly and loving, we would get devoured by those who were less so.
Through a series of studies, De Dreu found his hypothesis to be essentially correct:
“Results show that oxytocin creates intergroup bias because oxytocin motivates in-group favoritism and, to a lesser extent, out-group derogation. These findings call into question the view of oxytocin as an indiscriminate ‘love drug’ or ‘cuddle chemical’ and suggest that oxytocin has a role in the emergence of intergroup conflict and violence.”
To test his hypothesis, De Dreu’s team designed five experiments in which Dutch students were the in-group. In some experiments, the out-group was composed of Germans and in others, Arabs.
One of the experiments used a classic moral dilemma test, the sort of test where you’re in a full lifeboat with five others and a sixth man is drowning. Do you let the sixth man into the full lifeboat, possibly sinking the boat and sacrificing the lives of those in the boat with you? Would you let one person drown to save five?
In this scenario, the five in the lifeboat were nameless, but the drowning man had a name. Sometimes it was Dutch, other times it was German or Arab. The Dutch students who sniffed oxytocin were much more likely to save the man when his name was Dutch than those who sniffed the placebo. Dutch Maarten got fished out of the water more frequently than German Markus or Arab Muhammad.
Other experiments tested the time it took to link positive and negative adjectives with Dutch, German and Arab names. Those who took a whiff of oxytocin made the associations between positive words and Dutchmen much more quickly than those who sniffed the placebo.
This, De Dreu posits, happens not because the Dutch students dislike Germans and Arabs after breathing in oxytocin. They just like Dutchmen more. We don’t necessarily seek to harm those in the “out-group” — we just seek to protect those in the “in group” at all costs. Oxytocin doesn’t just make us want to cuddle — it makes us prefer our cuddle buddies at the expense of everyone else, a reaction that, according to De Dreu, “sets the stage for prejudice and social discrimination.”