he's mid-sentence and his face changes. the answers get shorter. then they stop. you've asked what's wrong, tried waiting it out, tried pushing through it, and somewhere in the silence a thought takes root: he doesn't care enough to fight for this. that thought is understandable. it's also, in almost every case, wrong. psychologists call it stonewalling, but the name undersells what's happening. couples wired to heart rate monitors during real arguments show the shutting-down partner has some of the highest heart rates in the room. his body has crossed a threshold it can't process in real time. past roughly 100 beats per minute, the prefrontal cortex goes offline. the part of the brain that handles reasoning and repair simply isn't available. nothing said in that state actually lands. research also finds men tend to reach this threshold faster than women do in conflict. it isn't avoidance. it's a nervous system reading danger and pulling the drawbridge up. recovery takes a minimum ...