Eye Contact Activates Brain Regions Involved in Social Behavior

Much of us already know that eye contact is very important when engaging someone in a conversation. But why exactly? A new study out of National Institute for Physiological Sciences in Okazaki, Japan, has just recently found important brain regions that are activated by achieving eye contact. The research, published in eNeuro by Dr. Norihiro Sadato, MD, Ph.D., and colleagues, tested the hypothesis using a hyperscanning functional magnetic resonance imaging (fMRI) that eye contact should activate the limbic mirror system, including the anterior cingulate cortex (ACC) and anterior insula (AIC). Their findings help explain the neurobiology behind social interactions.

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The research is based on the theory of automatic mimicry. This refers to nonconscious or automatic imitation of movement, a process which is very important for social interactions. Automatic mimicry has been proposed to have evolved in humans to allow us to show empathy and affiliation towards other humans. People have a tendency when interacting with someone to synchronize their facial expressions, posture, laughter, and yawning. These synchronizations, or mimicry, happen automatically without notice (unless you are looking for it).

Recent human imaging studies have shown that eye contact activates the "social brain". Scientists debate about the specific regions involved in this "social brain" but generally it includes the fusiform gyrus (important for recognizing faces), the temporal cortex, the medial prefrontal cortex, orbital prefrontal cortex, and the amygdala. However, the data which prompted their inclusion came from studies in which only one person was scanned. The current research used a two-person method, with both participants being scanned at the same time while they interacted with each other.

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This dynamic interaction implicated some unexpected areas. For example, areas in the cerebellum became active when participants made eye contact. The cerebellum has long had a reputation for mediating movements and balance, but more recent research suggests that it does a lot more. The cerebellum predicts future consequences of our behavior, detecting errors if our expectations are not met. It is also important for normal sensorimotor function. It uses sensory feedback to update future predictions.

As predicted the ACC and the limbic mirror system were both involved. Connectivity between the ACC and the AIC was enhanced while maintaining eye contact. Furthermore, there was inter-brain synchronization between the two participants in a region called the middle occipital gyrus (MOG). It is this inter-brain synchronization that is elicited by maintaining eye contact. It also suggests that we can (unconsciously) influence the brain activity of others through social interaction. While it is not necessarily mind reading, it certainly changes one's perspective about attending that next social event.

Sources: eNeuro, Virginia Tech, Neuroscience and Biobehavioral Reviews, Experimental Brain Research, Nature