These collections range from formal, scientific articles to informal tidbits in the daily press. Although the material collected here is loosely divided into categories, many of the items could easily be categorized in more than one category. They have not been.
Human behavior varies a lot. As compared with other primates, we're heavily influenced by culture, religion, family upbringing, and so forth. As a consequence, it's logical to conclude that our fitful monogamy is purely culturally induced and not instinctual. (On the other hand, we readily seem to accept that promiscuous tendencies are wired into our brains.)