Autism, a condition characterized by difficulties communicating and in forming relationships with other people, is the antithesis of social connectedness.

Those suffering from autism are reluctant to communicate with others, have a hard time making eye contact, and often avoid face-to-face interactions.

Maintaining direct eye contact can convey intimacy or threat, but because eye contact is difficult for autistic individuals to tolerate, they do not understand these silent messages.

Neuroscientists at the University of Wisconsin used MRI brain scans to study autistic traits and brain anatomy.

They also explored the relationship between eye contact and one of the emotional control centers of the brain, the amygdala.

The scientists found that the amygdala is significantly smaller in autistic children, and the smaller the amygdala, the less eye contact was observed in research subjects.

One explanation is that an autistic individual’s fear of eye contact and social interactions cause the amygdala to shrink. However, other studies suggest that these traits are genetically determined.

Researchers have found that non-autistic siblings of autistic children also show subtle reluctance to make eye contact and tend to have smaller amygdalae than normal children with no family connection to autism.

This family history of autistic traits suggests that the siblings — whether they are autistic or not — share a gene for autism inherited from their parents.