Dr. Stephen Porges on Oxytocin, Reproduction, and the Shutdown Response

Eric opened by asking about Sue Carter, Porges's wife, and her early work on oxytocin, bonding, and how that research connects to Polyvagal Theory. Porges answered with something close to a joke that carried a real point underneath it. For the first twenty years of their marriage, he said, the two of them ran separate research careers. Then they got reacquainted in the brain stem.

The overlap turned out to be more than coincidence. Carter was studying brain stem regions tied to oxytocin, and those same regions governed autonomic function. Oxytocin is a hormone, a chemical, but its reach extends to the autonomic organs and to the parts of the brain stem that keep the autonomic nervous system in check. For a long time people filed it away as a female hormone. Porges pushed back on that. It belongs to everyone, to all people and all mammals.

The reason it got labeled female had to do with childbirth and nursing. Delivery draws on the organs below the diaphragm, the uterus especially, and it involves pushing. A woman in labor cannot afford to shut down. The body does not defecate during birth unless there is pressure on the colon. Oxytocin lets that ancient vagal circuit do its job for reproduction instead of collapsing the system.

Sexual activity runs through the same machinery. The organs get used for pleasure and for contact without the shutdown reflex kicking in. This is where Porges drew a stark line between making love and rape. In both cases the body becomes immobilized. But one happens without fear, protected by oxytocin and by physiological feedback loops that hold you steady, and the other happens with fear and none of that protection.

Eric then turned to trauma, raising the question of how Polyvagal Theory accounts for self-regulation during something like war, in the aftermath once the event is over, and in PTSD. Porges was careful about his own footing here. He described himself as a laboratory scientist. He does the research, he finds things, he writes about them, but he has never been a clinician and still is not one.

When he first built the theory, trauma was not his subject. His focus sat on high-risk development, the life-or-death situations infants face. The connection to trauma came from the other direction. As he started describing the theory publicly, people who worked with trauma told him it mapped onto exactly what they kept seeing in their patients. People who had lived through trauma found the theory on their own and used it to put words to what had happened to them. Over and over, what they described was shutting down.