Hate the Lakers? Do the Celtics make you want to hurl?
Whether you like someone can affect how your brain processes their actions, according to new research from the Brain and Creativity Institute (BCI), housed in USC Dornsife.
Most of the time, watching someone else move causes a “mirroring” effect — that is, the parts of our brains responsible for motor skills are activated by watching someone else in action.
But a study by USC Dornsife researchers in PLOS ONE shows that whether you like the person you’re watching can actually have an effect on brain activity related to motor actions and lead to “differential processing” — for example, thinking the person you dislike is moving more slowly than he or she actually is.
“We address the basic question of whether social factors influence our perception of simple actions," said co-author Lisa Aziz-Zadeh, assistant professor with BCI in USC Dornsife and the Division of Occupational Science and Occupational Therapy.
Past research has shown that race or physical similarity can influence brain processes, and we tend to have more empathy for people who look more like us.
In this study, the researchers controlled for race, age and gender, but they introduced a backstory that primed participants to dislike some of the people they were observing: Half were presented as neo-Nazis, and half were presented as likable and open-minded. All study participants recruited for the study were Jewish males.
The researchers found that when people viewed someone they disliked, a part of their brain typically activated in “mirroring” — the right ventral premotor cortex — had a different pattern of activity for the disliked individuals as compared to the liked individuals.
Importantly, the effect was specific to watching the other person in motion. There was no difference in brain activity in the motor region when participants simply watched still videos of the people they liked or disliked.
"Even something as basic as how we process visual stimuli of a movement is modulated by social factors, such as our interpersonal relationships and social group membership," said Mona Sobhani, lead author of the paper and a graduate student in neuroscience in USC Dornsife. “These findings lend important support for the notion that social factors influence our perceptual processing.”
USC Dornsife's Jonas Kaplan, assistant professor of psychology and doctoral student Glenn Fox, both of BCI, were also co-authors of the paper.
“These results indicate that an abstract sense of group membership, and not only differences in physical appearance, can affect basic sensory-motor processing,” Aziz-Zadeh added.