Remember the Seinfeld episode where Jerry’s penis has an argument with his brain and loses? It’s a classic: We’ve all been torn between love/lust and logic. (If you haven’t, check for a belly button because this isn’t your home world.) This brilliant bit of comedy is totally relatable but a little misleading in one way: The brain is the one that sends signals to the penis in the first place. It’s pretty reliably running things, IMing the other body parts like crazy, regulating chemicals, making calculations and responding to stimuli, half the time without you even knowing about it. There’s a reason “the brains of the outfit” denotes someone who is really in charge.
So why does the brain sometimes signal us to do stupid things, especially in regard to sex and relationships? Isn’t that a little like one conjoined twin punching the other in the mouth? How does the brain decide who attracts us? What is it doing behind our backs, and how do we change as we mature?