New research by the Brain and Creativity Institute at USC determined that whether a person likes or dislikes someone can affect how their brain processes their actions.

Past research shows that the way your brain processes another person’s simple motor actions — such as finger movements — can be influenced by what the person looks like and whether they are more or less physically similar to yourself. For instance, people tend to have more empathy toward those who look similar to them.

The paper’s lead author, Mona Sobhani, said she wanted to add on to this research by looking into the effects of groups on perception. Sobhani is a third-year graduate student studying neuroscience at USC.

“We were interested in seeing if a construct like group membership — whether you belong to one social group or another — could alter the way your brain perceives someone else’s actions, when the person whose actions you are viewing is similar to yourself physically,” Sobhani said.

In the study, Jewish subjects were presented with likable people and Neo-Nazis. Researchers based the study on the perception that it is socially acceptable for Jewish individuals to dislike a social group that explicitly dislikes them and can even sometimes be threatening to them.

Participants viewed two-second video clips of subjects performing simple actions, such as drinking from a water bottle, and their responses were recorded. Before seeing the clips, the participants were informed that about half of the people in the videos held strongly anti-Semitic beliefs while others came from neutral backgrounds.

The participants were asked to rate how much they liked the subjects of the videos before and after they saw the clips. Analysis of the subjects’ responses to seeing each video clip revealed that the actions of Neo-Nazis were more unpleasant than the same actions performed by “likable” example individuals.

“This is an important finding because it suggests that an abstract social factor, and not a visual difference per se, can affect how you perceive the person,” Sobhani said. “It is especially interesting that this extends to such a simple motor action as reaching for and grasping a water bottle.”

Sobhani said the next step is to investigate whether the brain processes the actions of disliked individuals differently even if it is not socially acceptable to dislike them.

These results contribute to the longstanding evidence supporting the notion that perception of in-group and out-group members implicitly biases information processing in fundamental neural networks.