The volunteers didn't know the purpose of the
experiment. Participants thought they were vying against two other
people, but in fact they were playing a computer program.
The program treated the 13 subjects as outcasts
by intentionally excluding them from the game. It was an adult
version of being the "loser" who is picked last to play ball.
Social psychology graduate student Naomi Eisenberger
of UCLA and her colleagues worked on the study, which appears
in Friday's issue of the journal Science.
They found the volunteers' brains "lit up" when
they were rejected, just as our brains do when we experience physical
Specifically, neural activity was heightened
in the anterior cingulate cortex (ACC) the part of the
brain which responds to a punch or poke in the eye.
The researchers say the findings suggest any
type of social exclusion, from a divorce to not being invited
to a party to being turned down for a date, could cause distress
to the ACC.
Eisenberger said we may have evolved the tendency
to feel rejection as pain as a defensive mechanism since infants
need to stay close socially to survive.
If separation hurts, then children would learn
not to stray too far from their social group, she said.
Humans also need a defense mechanism to prevent
us from becoming overwhelmed by rejection, the researchers say.