The Absolutely Disgusting Reason Why Humans Started Kissing issing

A new study by Adriano R. Lameira, a psychology professor at the University of Warwick, challenges the common assumption that kissing has always been an expression of affection. Instead, Lameira’s research suggests that kissing likely evolved from a grooming behavior practiced by early primates for hygienic purposes, specifically for lice removal. He explains that in this grooming ritual, one primate would press its lips to another's skin, sucking debris or parasites from their fur. As humans evolved with less body hair, this grooming behavior lost its practical function, yet kissing persisted as a vestigial act, eventually taking on new social and affectionate roles.

The study notes that humans may have become "kissing apes" approximately 2 to 4 million years ago, with the earliest written reference to kissing found in Mesopotamian texts around 2500 BC. Although the transition of kissing into a sexual behavior remains speculative, Lameira proposes that kissing evolved into a mutual display of affection over time. Only once it was culturally associated with affection did it transform into a romantic or sexual gesture.