Abstract/Results: | ABSTRACT:
OBJECTIVES:
Social interaction is one of the most complex activities processed by the human brain. It requires complex interactions between many different cognitive systems, therefore the connections between these brain regions are likely to play a very important role in social competence. We examined brain connectivity in social cognition by studying eye-movements, social judgments, and psychophysiology in people born without the fibers connecting the left and right cerebral hemispheres, a condition called agenesis of the corpus callosum (AgCC).
METHODS:
Participants were 15 adults with complete AgCC (9 males, aged 16 - 52) and 10 healthy controls (all males, aged 19 - 48). Groups were matched on age (t = .22, p = .82). The control group had significantly higher FSIQ scores than the AgCC group (t = 2.77, p = .01). We recorded visual attention and physiological arousal as participants viewed 34 social and nonsocial images. Based on normative data, 17 slides were identified as “negative” and 17 as “neutral”. 11 of 17 negative slides and 6 of 17 neutral slides contained people. Participants rated images on Valence (9-point scale from negative=1 to positive=9) and Arousal (from calm=1 to exciting=9).
RESULTS:
Group differences on ratings depended on slide type. On negative images, the AgCC group gave lower arousal ratings (t=2.74, p < .05), but did not differ from controls on valence ratings. In contrast with neutral images, the groups did not differ on arousal ratings, but the AgCC group gave significantly more positive valence ratings than controls (t = 2.44, p < .05). Groups did not differ in number of fixations to negative images, but the AgCC group exhibited a trend toward significantly fewer fixations than controls on neutral images (t = 1.73, p = .10). With respect to people in the images, there were no group differences on rating of unpeopled
slides and no difference on valence ratings of peopled slides. However relative to controls, the AgCC group gave lower arousal ratings on peopled slides (t = 1.34, p = .028), primarily due to lower arousal ratings on negative slides with people.
CONCLUSIONS:
Despite intact visual attention to both social and nonsocial scenes, adults with AgCC appear to under-appreciate the intensity of negative emotions in people they observe. This may contribute to a positive-interpretation-bias in neutral situations. This study suggests that intact corpus callosum development is critical to development of social skills.
|