The Evolution of Oxytocin Spray

An interesting article from the Wall Street Journal details how the hormone oxytocin has evolved over millenia from a simple molecule that helped mothers identify their offspring, to a key mediator in the formation of trust and altruistic feelings toward fellow members of one’s group, and even transforming the interspecies relationship between cavemen and wolves into the bond we find today between modern man and his dog.

More oxytocin innovations emerged. In the eons since mammals proliferated on earth, some primate and rodent species independently evolved pair-bonding (that is, sexual and/or social monogamy). In the brain, oxytocin is heavily involved in this as well. And as primates developed complex you-scratch-my-back-I-scratch yours relations, evolution adapted oxytocin to mediate the formation of trust and altruistic feelings toward fellow members of one’s group.

So evolution’s oxytocin R&D team has filed one compelling new patent after another. But something truly striking occurred sometime in the past 50,000 years (which is to say, over the last 0.01% of the time during which oxytocin has existed). During that evolutionary blink of an eye, humans embarked on something new, with oxytocin again in a leading role: the domestication of wolves.

How did this occur? Reporting in the journal Science, Miho Nagasawa of Azabu University in Japan and colleagues observed that modern dogs and their owners secrete oxytocin when they interact with each other. Remarkably, dogs who gaze the most at their humans during interactions had the biggest oxytocin rise—as did their humans.