Author’s Note: The following is an excerpt from my review of Sex At Dawn: The Prehistoric Origins of Modern Sexuality. For additional information see my posts Reexamining Ardipithecus ramidus in Light of Human Origins, Those Cheating Testicles, or Who’s Your Baby? as well as Helen’s Lament and the Origins of Forbidden Love. Christopher Ryan also blogs at Psychology Today.

When we think of the first swinger parties most of us imagine 1970s counter-culture, we don’t picture Top Gun fighter pilots in World War II. Yet, according to researchers Joan and Dwight Dixon, it was on military bases that “partner swapping” first originated in the United States. As the group with the highest casualty rate during the war, these elite pilots and their wives “shared each other as a kind of tribal bonding ritual” and had an unspoken agreement to care for one another if a woman’s husband didn’t make it back home. Like the sexy apes known as bonobos, this kind of open sexuality served a social function that provided a way to relieve stress and form long-lasting bonds.

For the husband and wife team Christopher Ryan and Cacilda Jethá in their new book Sex At Dawn, this example is one of many that suggests the human species did not evolve in monogamous, nuclear families but rather in small, intimate groups where “most mature individuals would have had several ongoing sexual relationships at any given time.” We are the descendants of these multimale-multifemale mating groups and, even though we’ve constructed a radically different society from our hunter-gatherer forebears, the behavioral and psychological traits our species evolved in the distant past still manifest themselves today. Ryan, a psychologist, and Jethá, a psychiatrist, argue that understanding human sexual evolution this way helps to explain our species’ unique creativity inside (as well as outside) the marriage bed. It may also shed light on why fidelity has been such a persistent problem for both men and women throughout recorded history.

Read more at Seedmagazine.com.