"Moll and Jordan Grafman, neuroscientists at the National Institutes of Health, had been scanning the brains of volunteers as they were asked to think about a scenario involving either donating a sum of money to charity or keeping it for themselves.
As Grafman read the e-mail, Moll came bursting in. The scientists stared at each other. Grafman was thinking, "Whoa -- wait a minute!"
The results were showing that when the volunteers placed the interests of others before their own, the generosity activated a primitive part of the brain that usually lights up in response to food or sex. Altruism, the experiment suggested, was not a superior moral faculty that suppresses basic selfish urges but rather was basic to the brain, hard-wired and pleasurable."
So...there is some evidence that racial altruism or solidarity produces a pleasurable response in the brain of the typical human.
YET...we still see tribalism rampant in 21 century humanity. We understand that evolving a pleasurable altruism trait may be beneficial to humanity.
It feels good to be good to others, so if we're all good to each other, we'll all feel good together and that is a good thing.
But we compartmentalize, and segregate, and break down our species into smaller, easily sorted packages that we can conceptualize better.
Which brings up an interesting supposition. Do all these religious types who feel "all moral and warm" because of their faith, trigger this "pleasurable altruism" circuit in their brain through tribal solidarity of congregational fellowship?
Could this be part of the reason that so many people take comfort in tribal segregation - by joining a socieity that allows for maximum triggering of the "pleasurable altruism" circuit?
Sororities, Fraternities, Political Parties, Churches, Clubs, Gangs, Associations, Social Networking, Sporting Teams and Fan Associations - all may be humanity flailing around trying to maximize this triggering.