New research charts the surprisingly widespread response in multiple brain areas when the eyes of two individuals meet and social gaze interaction happens.
“There are strong robust signals in the brain that are signatures of an interactive social gaze,” says Steve Chang, associate professor of psychology and neuroscience at Yale University, a member of the Wu-Tsai Institute and the Kavli Institute for Neuroscience, and the senior author of the study.
The phenomenon of extracting meaning in the gaze between two people has been documented in art and literature for millennia but scientists have had a difficult time uncovering how the brain accomplishes such a subtle feat.
Chang’s lab overcame this obstacle by monitoring the brain activity of monkeys while simultaneously tracking the eye positions of two animals. This enabled them to record a large array of neurons as the animals spontaneously gazed at each other.
“They were spontaneously engaging in social interactions while we examined neural firing,” Chang says. “Importantly, we were not imposing any tasks, so it was up to them to decide how and when they would interact.”
The brain regions in which neuronal activation took place provided hints into how the brain assesses the meaning of the gaze. Surprisingly, part of the network activated during social gaze interaction included the prefrontal cortex, the seat of higher-order learning and decision-making, as well as the amygdala, the center for emotion and valuation.
“Multiple regions within the prefrontal cortex, in addition to the amygdala, are recruited to compute selective aspects of interactive social gaze, suggesting the importance of a more contemplative role during social gaze interaction,” Chang says.
“The fact that interactive social gaze neurons are found widely in the brain also speaks to the ethological importance of social gaze interaction,” Chang says.