Humans are highly social creatures and wherever we go we subtly modify our behavior to fit in with others. Rudeness signals that one is not welcome in this group, activating pain regions in the brain as found by Naomi Eisenberger and colleagues at UCLA. Rudeness also shows that others don't trust us. As I report in my new book The Moral Molecule: The Source of Love and Prosperity, when men are distrusted, they experience a sharp spike in testosterone provoking an aggressive response of the type "How dare he...." Women have this response, too, it is just more muted.
Good manners, on the other hand, are a reflection of the Golden Rule: if you are nice to me, I'll be nice to you. The Golden Rule exists in every culture on the planet. A likely reason for this is our hyperactive connection circuitry in the brain that prominently uses the neurochemical oxytocin. As I discuss in The Moral Molecule, in a decade's worth of experiments in the laboratory and in the field, my colleagues and I have found that when someone is nice towards another person, the recipient's brain releases oxytocin and this causes him or her to respond with kindness. Oxytocin is the embodiment of the Golden Rule.
An extraordinary triumph of the human species is our ability to extract value from all kinds of relationships with all kinds of people. One never knows when the server at the cafe you frequent might become a neighbor, or romantic partner, or work colleague, or perhaps a friend. Maintaining good relationships with a large number of people broadens our ability to find opportunities to profit from relationships. This "profit" might be a business opportunity, but more often it is the value of companionship that expands our social network. Individuals with the richest social networks are happier, healthier and live longer.
So how do you improve your social life? My experiments have found that those who release the most oxytocin when they are trusted have higher quality relationships of all types: romantic, friendships, and with family members. And, importantly, they share more money with strangers in laboratory tasks. I'd call this good manners.
Here's a way to start broadening your social network: say hello to people you meet. Good manners also dictate that you treat them with respect and kindness. Just the thing your mother probably told you when you were a child, but this is advice that resonates with the neuroscience of oxytocin. By the way, high stress inhibits oxytocin release and the reciprocation of nice with nice. So if someone is rude toward you, you don't have to lash out at him or her. Give them the benefit of the doubt--they may just be having a high-stress day. Oxytocin lets us behave with compassion for others by allowing us experience others' emotional states.
Here's a way to take it one step further: next time someone is rude to you, offer him or her a hug. It is an easy way to diffuse the situation by getting their brains to release oxytocin and reduce the stress they are experiencing. Hey, it might even work if the person is French.