Volunteers played a simple game, modeled after foraging in the wild, against a computer-controlled competitor. Players chose one of four boxes, which paid out varying sums of money. To maximize winnings, a player had to occasionally sample each of the boxes. When players saw their competitors get an unexpectedly high sum, functional MRI scans showed no measurable brain activity in reaction. When the drones got an unexpectedly low payout, however, parts of a player's brain associated with inhibition went bonkers.
I wonder if this is why it's a common human tendency to focus more on our own mistakes than our own successes. Is it a hardwired method of learning? Perhaps at one time it meant that humans could avoid getting eaten by a tiger or falling off a cliff. That would be useful. Too bad it gets over-generalized to misery and anxiety over non-tigerish situations.