Every man has probably had this experience. You're in an argument with your wife/girlfriend and, just when you think the argument is over, she suddenly dredges up some ancient thing you did wrong 20 years ago that you can't even remember and starts the fight all over again.

As a man, I've always said "WTF!?" to myself as such moments. Why in the hell is she picking a fight about something that I don't even remember?

I've always written it off as further evidence of female insanity. But science has actually come up with an answer.

Emotion, it seems, is largely a result of our brain interpreting what our body is doing. So, when we're pissed off about something; our heart rate increases, our pupils dilate, etc. Our brain senses this and we experience anger, or fear, or whatever seems appropriate.

These responses are beyond our conscious control and are controled by our autonomic nervous system. In men, once a situation is resolved, the autonomic nervous system quickly returns to normal and we cease to experience the emotion associated with the event. Thus, when the fight is over, we cool off right away.

But in women the autonomic half life is about double that of men. So when a fight is over and whatever you were fighting about is resolved; a woman's brain still detects all the symptoms of anger. So what does it do? It searches for something to be angry about. The result? The seemingly irrational female picking a fight over something the man can't even remember.

Half-life of the autonomic nervous system.

If you ever have arguments with people of the opposite sex, the following may be the most valuable advice you will receive all year.

In humans, strong emotion starts with physiological changes in your body, not with an awareness of the emotion in your brain. So when somebody pisses you off, your heart rate increases, your adrenaline surges, and your muscles tighten up even before you realize that you’re angry. Or, as William James wrote, “we feel sorry because we cry, angry because we strike, afraid because we tremble,” not the other way around.

According to neurobiologist Robert Sapolsky, men and women are about the same in the speed with which their physiology gets engaged in strong emotions. However, in women, the nervous system takes a bit longer to “settle down” and return to normal than it does in men.

What this means is that as an argument winds down, a man will start feeling calmer relatively quickly — while a woman’s body remains in an agitated state even after the apparent resolution of the argument. Because everyone’s brain takes cues from the body, her brain realizes it’s still angry. So it starts casting about for other things to be angry about. Bam: Suddenly the argument flares up again, about a new subject.

Sound familiar? Fortunately, once you know about this, it’s not too hard to figure out how to handle it, whether you’re male or female. If you’re a man arguing with a woman, once the argument seems to be winding up, it’s time to say something funny, switch the subject to a completely different (non-controversial) topic, or do something nice for her. If you’re a woman, you need to remind yourself to go chill out, step into a different room, or do something to calm down before you reignite the argument.

Or, as Sapolsky and his wife do, you can just remind each other, “Honey, don’t forget what the half-life is on the autonomic nervous system!”

Thoughts?