Affiliative behavior in Williams syndrome: social perception and real-life social behavior

Abstract

A frequently noted but largely anecdotal behavioral observation in Williams syndrome (WS) is an increased tendency to approach strangers, yet the basis for this behavior remains unknown. We examined the relationship between affect identification ability and affiliative behavior in participants with WS relative to a neurotypical comparison group. We quantified social behavior from self-judgments of approachability for faces, and from parent/other evaluations of real life. Relative to typical individuals, participants with WS were perceived as more sociable by others, exhibited perceptual deficits in affect identification, and judged faces of strangers as more approachable. In WS, high self-rated willingness to approach strangers was correlated with poor affect identification ability, suggesting that these two findings may be causally related. We suggest that the real-life hypersociability in WS may arise at least in part from abnormal perceptual processing of other people's faces, rather than from an overall bias at the level of behavior. While this did not achieve statistical significance, it provides preliminary evidence to suggest that impaired social-perceptual ability may play a role in increased approachability in WS.

Figure 1

Means and standard error means (±1 SEM) for the ratings of the participants with WS and their TD counterparts across the SISQ subscales, as well as for the Global Sociability score (maximum rating per scale = 7). All between-group contrasts except for Approach Familiars p ≤ .001)

Figure 2

Mean approachability ratings for each face stimulus by participants with WS and TD. The stimuli are rank-ordered on the x-axis according to their pre-judged approachability ratings. Thus, the most negative stimuli are presented at the far left, and the most positive stimuli are presented at the far right

Figure 3

Images of affective expression used in the stimuli of experiment 3

Figure 4

Mean facial affect identification scores and standard error means (±1 SEM) for participants with WS and TD (maximum score per category = 2)

Figure 5

Scatter-graph plotting total self-rated approachability scores (Experiment 2) against total affect identification scores (Experiment 3) for the WS and TD groups