Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff, Lauren vogelbam here. If you've ever had the distinct pleasure of sourcing stock photos for any reason, you've likely come across a whole lot of laughing women eating salads alone. But you've also probably stumbled upon a truckload of people scratching their heads to symbolize confusion, deep thought, or perhaps a bad case of dandruff scalp dryness. Aside, how exactly
did the head scratch come to symbolize intellectual processes? Some people believe that certain automatic gestures are simply natural, expressive motions that are caveman predecessors passed down to us. San Diego reader columnist Matthew Alice wrote this about it. One popular explanation for any hand to head movements is that their frustrated aggression a reversion to the natural movements of
our rock throwing ancestors. If you watch a small child strike at something, he'll raise an arm over his head and bring it forward in an arc. It's an natural, unstudied movement, not much finesse, but for a caveman it got the job done. Alice also pointed to a possible anthropological explanation for head scratching. He wrote, when we're wrestling with some knotty problem, we experience feelings of frustration, perhaps some anger, and before we know it, our hand flies
up in the air. But hold it. In these modern times, it's not polite to bash the guy who asked the question, so instead we deflect attention from the movement and scratch or rub our head or chin or neck. In a two thousand nine article for Psychology Today, author and former FBI counter intelligence agent Joe Navarro wrote, when we are under stress, our brain requires a certain amount of hand to body touching, handwringing, forehead rubbing, temple massaging, lip touching, etcetera.
These pacifiers serve to soothe the individual when there is negative limbic arousal, fear, stress, etcetera. Recent research seems to back up this stress theory and add another unexpected layer to the story. In a two thousand and seventeen study which was published in the journal Scientific Reports, scientists who observed forty five recent monkeys found that scratching was more likely to occur in times of heightened stress, like standing in the presence of a high ranking or unfamiliar monkey.
It turns out monkeys who scratched were significantly less likely to be attacked by those threatening strangers. Lead author Jamie Whitehouse said in the study, as scratching can be a sign of social stress, potential attackers might be avoiding attacking obviously stressed individuals because such individuals could behave unpredictably or be weakened by their stress, meaning an attack could be
either risky or unnecessary. And meanwhile, itching is still a pretty mysterious phenomenon to scientists, but recent research suggests the tickly sensation isn't necessarily a mild form of pain, but its own distinct occurrence caused by a molecule that sends a message from the heart to the spinal cord. So while there's no single explanation for this head scratcher, you know what was coming. It appears that acting out your anxiousness with this stereotypical tick could keep you in the
good graces of others. Today's episode was written by Michelle Konstantinovski and produced by Tyler Clang. If you love our show and want to wear your heart on your sleeve, check out our new shop te public dot com. Slash brain Stuff for shirts and other merchandise, and of course, for more on this and lots of other topics that will scratch your itch for knowledge, visit our home planet, how stuff Works dot com