Ben Mocha retrieved data from 4,572 accounts of cultural studies—ethnographies—and studied them looking for what he describes as normal sexual practices… He found that virtually every known culture practices private mating—even in places where privacy is difficult to find. He also looked for examples of other animals mating in private, and found none, except for the babblers. He also found that there were no explanations for it, and in fact, there were very few other people wondering why humans have such a proclivity. And, not surprisingly, he was unable to find any evolutionary theories on the topic.
Ben Mocha concludes his paper by introducing a theory of his own—he believes that the reason humans (and babblers) began looking for privacy during sex was because the male wanted to prevent other males from seeing his female partner in a state of arousal. Such a state, he suggests, would likely have encouraged other males to attempt to mate with her. Thus, privacy, or perhaps more accurately, seclusion, allowed the male to maintain control over a sexual partner—while also allowing for continued cooperation within a group. He further suggests that the study of the evolution of private mating could lead to a better understanding of how thinking skills in humans matured as they learned to function in groups.
National Review’s Wesley J. Smith has a different perspective.
This approaches the question from the wrong angle. There is much more to human life than biology. We are not just a collection of carbon molecules and the sum of our genes expressing. We are more than intelligent apes. There is a deeper side to us, something that can neither be measured nor fully explained from exclusively materialistic analyses…
Sex is profoundly consequential morally. We are not just animals yielding to an irresistible biological imperative when the female goes into estrus. For us, intimacy isn’t — or ideally, shouldn’t be — mere rutting. Moreover, sex is something we can choose to refuse based on moral considerations. Animals do not have that ability.
Indeed, sexual morality is one of the most important factors in creating culture. That is the reason those who wish to destroy existing paradigms subvert cultural status quos through transgressive sexual advocacy and/or behavior.
Bottom line: Evolution doesn’t explain everything in human nature or the development of culture. It can’t. We have stepped beyond subjugation to the immutable forces of natural selection. We are self-directing, and that includes our approaches to sex.
Abandon human exceptionalism in anthropology, treat us as if we are just another animal in the forest, and the discipline misses the forest for the trees.