Edit: When I say "no biological purpose", that's a bit of a misnomer. I mean that it does not directly lead to the perpetuation of the species. I know it does serve some biological purposes technically, so I misspoke when I said that. I was just wondering if kissing was a cultural phenomenon as opposed to a biological drive, and if so, if anyone knew what culture it originated in.
This question might receive answers written with more authority in the sub /r/Askanthropology.
I think most of what you want to know is in this old post of mine:
While romantic kissing is not human universal, in many societies that practice it, its origins are ultimately pre-historic so we don’t know how it started. Mothers (and perhaps fathers) kissing children may be a human instinct (I haven't seen definitive research on this, though I have read that it may help transfer children's germs to mothers so that mothers can produce anti-bodies in breast milk—this is, however, just a theory last I checked). Romantic kissing is definitely a cultural phenomenon, however.