Seems to me that every culture has kissing as a commonly accepted form of affection. Has this always been the case? Or was/is there a culture where kissing wasn't common? I mean it seems that it's just natural and that everyone has the urge to kiss the person(s) they love. But is that an inherit urge in humans? Or is it just because we have been raised to view kissing as such?
You may want to ask the anthropologists over in our sibling subreddit /r/AskAnthropology, or over in /r/AskSocialScience.