Initially, participants were included in the activity but were then excluded when the two other "players" stopped throwing the ball to them.
"What we found is that individuals with the rare form of the OPRM1 gene, who were shown in previous work to be more sensitive to physical pain, also reported higher levels of rejection sensitivity and showed greater activity in social painrelated regions of the brain the dorsal anterior cingulate cortex and anterior insula in response to being excluded," Eisenberger said.
The dorsal anterior cingulate cortex and anterior insula are brain regions often associated with the distress of physical pain. Previous research by Eisenberger and her colleagues has shown that these brain regions are also involved in the pain of social rejection.
"Although it has long been suggested that mu-opioids play a role in social pain and there are convincing animal models that show this this is the first human study to link this mu-opioid receptor gene with social sensitivity in response to rejection," Eisenberger said.
"These findings suggest that the feeling of being given the cold shoulder by a romantic interest or not being picked for a schoolyard game of basketball may arise from the same circuits that are quieted by morphine," said Baldwin Way, a UCLA postdoctoral scholar and the lead author on the paper.
Eisenberger argues that this overlap in the neurobiology of physical and social pain makes good sense.
"Because social connection is so important, feeling literally hurt by not having social connections may be an adaptive way to make sure we keep them," she said. "Over the course of evolution, the social attachment system, which ensures social connection, may have actually borrowed some of the mechanisms of the pain system to maintain social connections."
|Contact: Stuart Wolpert|
University of California - Los Angeles