I’ve heard that it likely started by moms or grandmothers who pre-chewed food for toddlers who needed to stop nursing, so the mother would be more free to contribute work to the families survival, or to have more children, which can improve survival on a tribal scale.
Either way, when young men want a sexual partner, kissing is a solid pre-requisite to arousing a potential mate, so men kiss to get women horney.so then, the real question is, why would females be evolved to enjoy kissing before choosing a mate?
One possible answer is that it allows the female to get a better sample of pheromones and other chemical markers that can imply health and physical compatibility. Females may not even realize that these influences are at play.
Of course, who knows?
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