The kiss can have many meanings, and is regulated by as many social norms as there are peoples and cultures on our planet. How does such an intimate and widespread gesture come about? Evolutionary psychologist Adriano Lameira, of the University of Warwick, believes he has found the answer. In his latest study, published in the journal Evolutionary Anthropology, he proposes that kissing is a ritualized behavior that derives from grooming, that repertoire of grooming gestures used by many primates, probably including our hominid ancestors, to form and strengthen social bonds , and affirm hierarchies within the pack.
The previous hypotheses
As Lameira explains in his work, the proposals put forward in the past to explain the origin of the kiss have never fully convinced the scientific community. It has been said, for example, that kisses could have originated in the evolution of female lips (fuller than male ones) as a character with sexual value. Or that kisses are a form of social inspection, a way to “smell” other specimens of our species and evaluate their state of health. Hypotheses which, however, struggle to explain the many forms, and the many values, that kissing takes in our species today.
Another category of theories is that which seeks the biological root of kissing in the relationship between mothers and newborns. In this case, it would be a gesture that arises from the way in which children suck their mothers’ breasts, or from the way in which mothers (in the distant past) chewed food and then offered it to their children. For Lameira, even these hypotheses – although more plausible than the previous ones – struggle to really explain the context in which we use kisses today, and the social functions we attribute to them. Where to find an alternative theory? Lameira decided to focus on the social value that we attribute to the kiss, as a gesture with which we tighten and strengthen emotional bonds, and to look at the behaviors that play a similar role in our primate cousins.
Grooming
With the term grooming, ethologists refer to the practice of “grooming” or grooming one’s conspecifics, which in many primate species is a ritual that plays a fundamental social role. It is through grooming that bonds within the pack are formed and nurtured, and from the duration of grooming it is usually possible to deduce the hierarchies between its members and the strength of the relationships between the different specimens. Hence, Lameira’s hypothesis. If our ancestors practiced grooming, it is possible that this habit survived even as evolution led us to slowly lose our fur. With less hair, obviously, the need to be groomed also progressively decreased, consequently reducing the duration and the repertoire of gestures that made up grooming, to the point of seeing its usefulness in eliminating parasites completely disappear, ultimately maintaining only that of social glue, and gesture of intimacy.
In monkeys, grooming ends with a gesture in which the animal’s lips are protruded forward, similar to what happens in our kisses. For Lameira, this could be the clue that kisses are what remains of the movements carried out in the past during grooming, which have today been transformed into a vestigial gesture, which has lost any practical utility, and only maintains an emotional and social value. He has named his proposal “groomer’s final kiss hypothesis” and now wants to investigate the issue more thoroughly, proceeding with an accurate cataloging of the gestures that make up grooming activities in different primate species. , to see how they change based on the density of their fur. And how likely it is, therefore, that by losing his hair man has somehow maintained the “habit” of kissing.