

Are these men sniffing? (REUTERS/Jim Bourg)

We have long known that liberals are more likely to choose other liberals as romantic partners and that conservatives also tend to prefer mates with similar political viewpoints. Indeed, other than religion, ideology is a stronger correlate than other traits in the selection of long-term partners. But how does this work?

A new article in the American Journal of Political Science by Rose McDermott (Brown), Dustin Tingley (Harvard), and Peter Hatemi (Penn State) suggests that the explanation could be that liberals and conservatives smell differently and that each prefers the smell of ideologically similar persons. That body odor influences attraction is well-established. The authors argue that smell signals also serve other functions, such as disease avoidance, cheater detection, defense against outgroups, and social cohesion. These may be related to political ideology. For example, they note:

[..] greater disgust sensitivity, which is intimately interconnected with the neural substrates of smell, predicts more conservative positions, particularly around issues involving morality and sexual reproduction. These underlying, physically experienced predilections can come to be expressed as opinions on such topics as abortion, homosexuality, gay marriage, and a host of other ideological topics

They then claim:

If social attitudes are linked to odor [..] then one mechanism that odor preferences transfer from parents to children may operate through their mother’s choice of mate. In this way, social processes may drive some of the pathways by which individuals come to prefer those whose ideological “smell” matches their own.

The researchers asked a group of ideologically diverse people to rate the body scent of both liberals and conservatives (without seeing them in person). On average, ideologically similar people appreciated the scent of similarly disposed people more. So, scent could be a way in which we subconsciously select mates of similar dispositions.

Before the more creative among us go out and create perfumes for liberals and conservatives, I should note that the effect is very small and teeters on the edge of what we would normally call statistically significant. That is: we are not as certain as we would ideally like to be that the finding isn’t a consequence of mere chance. There are probably other more important mechanisms that produce sorting on ideology than smell. Still, it’s an innovative new study on the link between biology and politics.