This has been a golden age for brain research. We now have amazing brain scans that show which networks in the brain ramp up during different activities. But this emphasis on the brain has subtly fed the illusion that thinking happens only from the neck up. It’s fed the illusion that the advanced parts of our thinking are the “rational” parts up top that try to control the more “primitive” parts down below.

So it’s interesting how many scientists are now focusing on the thinking that happens not in your brain but in your gut. You have neurons spread through your innards, and there’s increasing attention on the vagus nerve, which emerges from the brain stem and wanders across the heart, lungs, kidney and gut.

The vagus nerve is one of the pathways through which the body and brain talk to each other in an unconscious conversation. Much of this conversation is about how we are relating to others. Human thinking is not primarily about individual calculation, but about social engagement and cooperation.

One of the leaders in this field is Stephen W. Porges of Indiana University. When you enter a new situation, Porges argues, your body reacts. Your heart rate may go up. Your blood pressure may change. Signals go up to the brain, which records the “autonomic state” you are in.