Individuals with autism rely more on words than on facial expressions when interpreting social cues, and this may result from low activity in two brain regions, according to a paper published 22 June in PLoS One¹.

People with autism often have trouble processing subtle social cues², especially when given conflicting information — for example, a person saying something nice while looking and sounding angry.

The researchers scanned the brains of 15 men with autism and 17 controls as they watched short videos of actors saying words that either conflicted or were consistent with their facial expressions and tones of voice. For example, in a conflicting scenario, a man would say “dirty” while smiling and sounding happy.

Men with autism are more likely than the controls to rely on a word’s meaning rather than on a facial expression when the two are not in agreement, the study found.

Using functional magnetic resonance imaging, the researchers analyzed activity in a number of brain regions involved in emotion and empathy. When watching videos with conflicting information, men with autism show less activity in the anterior cingulate cortex and the dorsomedial prefrontal cortex than controls do.

The researchers also assessed the participants’ communication skills using the Autism Diagnostic Interview-Revised, a parent questionnaire. Participants with autism who score lower on the communication part of the questionnaire, which includes questions about things such as body language, have less activity in the anterior cingulate cortex and the dorsomedial prefrontal cortex than those with higher scores.

The results suggest that low activity in these regions may make it challenging for a person to process social cues and may underlie the social deficits seen in people with autism, the researchers say.