Rejection really hurts finds brain study

October 9, 2003
Philip Cohen

Lonely hearts have spent millennia trying to capture the pain of rejection in painting, poetry and song. Now neuroscientists have seen it flickering in some remarkable brain images from college students suffering a social snub.

The brain scans reveal that two of the same brain regions that are activated by physical pain are also activated by social exclusion.

"This doesn't mean a broken arm hurts exactly the same way that a broken heart does," says Matthew Lieberman of the University of California, Los Angeles, who led the research. "But it shows that the human brain sounds the same alarm system for emotional and physical distress."

Eventually, by targeting drugs to these regions, he says it may be possible to develop powerful new medications for extreme cases of social anxiety or depression.

"This is evidence that humans don't build complex emotions out of thin air," says Jaak Panksepp, of Northwestern University in Evanston, Illinois, who has studied how the same regions are involved in social interactions in many mammals. "These emotions are built on basic tools that evolution gave us a long time ago. "

Emotional alarm system

Lieberman describes the anterior cingulate cortex (ACC) as an emotional alarm system that draws the brain's attention to distressing or unexpected changes in the environment. The region lights up in response to pain, for instance, but also when a mother hear an infant's cry. But no one had tested whether social rejection also activated this area in humans.

So the researchers used functional magnetic resonance imaging to view the brains of nine female and four male college students who volunteered to play a computer game. In the game, they caught and threw a ball with two other players. Each participant was told they were interacting with other students, but in fact the other players were controlled by the computer.

In the first part of the experiment, the participant was told technical problems prevented them from playing, so they could only watch. In the second half, they were able to catch and throw the ball to the player of their choosing. But after they received the ball seven times, the computer stopped throwing the ball to them for the remaining 40 or so tosses.

Afterwards, each student was asked about their level of distress at being given the cold shoulder by the other players.

Thirst and hunger

In both parts of the experiment, the ACC lit up and was more active in students who reported greater distress. During the second experiment, another region called the right ventral prefrontal cortex, which animal studies have linked to reducing suffering from pain, was also activated.

Lieberman speculates that this region also helps cope with the "pain" of social exclusion, but may only be activated when a cause can be identified, which was not the case in the first experiment.

The fact that disruption of even a trivial virtual relationship can activate the ACC shows how hard wired the response is. "The need for social connectiveness isn't just something self-help authors cooked up," says Lieberman. "It's a basic need programmed into a primitive part of our brains like thirst and pain and hunger."

Science (vol 302, p 290)