Kissing is not universal among human beings, and, even today, there are some cultures that have no place for it. This suggests that it is not innate or intuitive, as it so often seems to us. Another possibility is that kissing is a learned behavior that evolved from "kiss feeding," the process by which mothers in some cultures feed their babies by passing masticated food from mouth-to-mouth. Yet, there are some modern indigenous cultures in which kiss feeding is practiced, but not social kissing. Kissing could also be a culturally determined form of grooming behavior, or, at least in the case of deep or erotic kissing, a representation, substitute for, and complement to, penetrative intercourse.
https://www.psychologytoday.com/blog/hid...ry-kissing
https://www.psychologytoday.com/blog/hid...ry-kissing
