The new book Sex at Dawn: The Prehistoric Origins of Modern Sexuality has been getting a great deal of buzz lately, especially with the co-authors' strong refutation that monogamy is not natural for humans. A number of polyamorists and sex radicals have been posting "told-you-so" commentary on blogs and social network pages -- and I can only imagine what more conservative folks are thinking.
Having studied social and behavioral science, I'm always skeptical of any extreme claims about human nature, whether it's about being "hard-wired" one way or another, or the old-fashioned "blank slate" theory. Neither is entirely accurate, even when talking about something as instinctive as sexuality.
For one thing, humans have enormous variability, even in the most basic elements. Some individuals have powerful libidos, while others have little to none. The question of sexual behavior -- how we channel that desire -- is as much molded by culture and psychology as it is by hormones and neurons.
Sex at Dawn provides great scientific insights, and challenges long-held preconceptions about human sexuality. But it's far from a handbook on sexual ethics. Even if we are "wired" for promiscuity, that doesn't mean we're compelled to get it on with anyone and everyone who turns us on. Our brains are also wired for more complex emotional relationships, and to anticipate long term consequences. And a sound ethical approach is one which finds a balance between primal instinct, social necessity, and individual variation.
Human nature is complex, including human sexuality. Just as we need to be skeptical about the false dichotomy of biological determinism versus tabula rasa, we also need to reject the either-or fallacy of "traditional morality" versus "moral chaos". Hopefully the buzz around this book will open people's eyes to the ethical approach adopted by polyamorists and others -- one based on consent and respect, including respect for the realities of human diversity.