When evolution goes wild: Kissing
Last week, I wrote about how evolution can sometimes go astray and lead to strange outcomes in our modern societies. One of the studies I mentioned showed that societies in areas of the world with higher frequency of diseases evolved to be less individualistic and more collectivistic.
This evolutionary process also works on a different level: In relationships. Kissing each other on the mouth is a habit that is widespread across the world, yet not universal. There are cultures where mouth-to-mouth kisses don’t exist.
If you think of it from an evolutionary perspective, kissing a mate on the mouth is potentially a very dangerous activity. It is an intimate process where saliva is shared between the two participants – and with it potentially pathogens. As a result, in the initial stages of a relationship, people should be hesitant to kiss a potential mate, while they should be more likely to kiss an established partner. And that is exactly what sociologists have found. The frequency of kissing increases for couples that are in a well-established relationship compared to couples in the courtship phase of a relationship.
People who have more to lose from kissing are more reluctant to kissing in the initial stages of a relationship, i.e. women and more attractive people who can be more selective. However, what is important in the initial stages of a relationship is the quality of the kisses. What determines the quality of a good kiss? Don’t laugh, but the number one criterion is good breath. After that, it is, of course, physical arousal, which gives an obvious clue as to how good a partner would be as a potential mate and “gene donor”. Thus, in the courtship phase the rule is quality over quantity.
However, once a relationship is established, quantity becomes more important than quality. Again, from an evolutionary perspective this makes sense. The main purpose of a partnership is to share resources to raise children. Kissing your partner on the mouth becomes a form of confirmation that the bond between you and your partner is still intact. Similarly, kissing is a form of checking in with a partner to see if he or she still loves you. Being able to assess how much your partner still loves you becomes even more important if you live in a society that is very unequal, where splitting up may mean a much steeper fall economically. Hence, researchers predicted that in societies with higher income inequality, there should be a higher frequency of kissing amongst couples. And that is indeed what can be observed. Couples kiss each other more frequently in unequal societies like the United States, Brazil or Columbia than in more equal societies like Germany, France or Italy.
What does all of that have to do with investing? Nothing at all. It’s just a reminder that as we head into winter and if you are in a stable relationship, make sure you kiss your partner often. It really is the best thing to keep your relationship strong and healthy.
Income inequality and frequency of kissing
Source: Watkins et al. (2019).