Some parents of children with autism evaluate facial expressions differently than the rest of us - and in a way that is strikingly similar to autistic patients themselves, according to new research by psychiatrist Dr. Joe Piven of the University of North Carolina at Chapel Hill and neuroscientist Ralph Adolphs, Ph.D., of the California Institute of Technology.
Piven, Adolphs and colleague Michael Spezio, Ph.D., formerly of Caltech but now at Scripps College in Claremont, Calif., collaborated to study 42 parents of children with autism, a complex developmental disability that affects an individual's ability to interact socially and communicate with others. Based on psychological testing, 15 of the parents were classified as being socially aloof.
"This manifests as a tendency not to prefer interactions with others, not to enjoy 'small talk' for the sake of the social experience and to have few close friendships involving sharing and mutual support," said Piven, senior author of the study, Sarah Graham Kenan professor of psychiatry in the UNC School of Medicine and director of the newly established Carolina Institute for Developmental Disabilities. "This characteristic is really a variation of normal and not associated with any functional impairment."
The parents participated in an experiment that measured how they make use of the face to judge emotions. The subjects were shown images depicting facial expressions of emotion that were digitally filtered so that only certain regions of the face were discernible - the left eye, for example, or the mouth. The subjects were then asked to decide as quickly as possible if the emotion depicted was "happy" or "fear." The part of the face shown and the size of the revealed area randomly varied from trial to trial.
An analysis of the subjects' correct responses revealed that "aloof" parents relied much more heavily on the mouth to recognize emotion than they did on the eyes, as compared to non-aloof parents and, to a greater extent, to a group of parents of children without autism. Prior studies by Adolphs and his colleagues have shown that humans normally evaluate emotions by looking at the eyes - but studies by Adolphs and Piven have shown that individuals with autism do not.
"We found that some parents who have a child with autism process face information in a subtly but clearly different way from other parents," Adolphs said. "This is evidence for the hypothesis that the parents with the autistic child have brains that function somewhat differently as well."
He and other researchers are currently investigating that idea through brain imaging studies. One area of interest is the amygdala, a region located on either side of the brain in the medial temporal lobe that is known to process information about facial emotions and may have abnormal volume in both autistic individuals and their nonautistic siblings.
The finding indicates that certain aspects of autism do run in families. Although such a genetic link was noted in the 1940s in the earliest descriptions of autism, "our study adds considerable specific detail to the story," Adolphs said.