Comprehension of Communicative Intent Behind Pointing and Gazing Gestures by Young Children with Williams Syndrome or Down Syndrome

• ¹ University of Louisville, Department of Psychological and Brain Sciences, United States

Background and Purpose: Although individuals with WS evidence a relative strength in concrete vocabulary, recent research has documented significant weaknesses in pragmatic abilities even in very young children. For example, the communicative behavior of toddlers and preschoolers with WS (e.g., gaze shifting, participation in joint attention, production of gestures, tracking distal pointing gestures) is well below both chronological age (CA) and mental age (MA) expectations. To further explore pragmatic abilities during the preschool period, we conducted a study comparing the ability of young children with WS or Down syndrome (DS) to recognize communicative intent as expressed through non-linguistic gestures (eye gaze or pointing) in the context of a hiding game modeled after Behne, Carpenter, & Tomasello (2005).

Methods: Participants were 33 children with WS (17 boys, 16 girls) aged 3.00 to 5.32 years (m = 4.14 years, SD = .68) and 25 children with DS (11 boys, 14 girls) aged 3.02 to 5.40 years (m = 4.34, SD = .73) matched on CA (p = .29). Mean DQ on the Mullen Scales of Early Learning was significantly higher for the WS group (59.0) than the DS group (52.5); the WS group also scored significantly higher on the Mullen Receptive and Expressive Language Scales. During the hiding game, the experimenter hid a toy in one of two identical containers, established eye contact, and then provided a communicative or noncommunicative cue (involving gaze shifting or pointing) to indicate the container in which the object was hidden. Each child participated in four conditions formed by crossing Communicative style (communicative vs. noncommunicative) and Gesture type (point vs. eye gaze shift). The non-communicative conditions were presented first to avoid biasing the child’s attention. Order of presentation of Gesture type was counterbalanced.

Results: Comparisons of performance in the communicative and non-communicative conditions to chance indicated that communicative cues were used significantly more often than expected by chance (p < .005) to find the hidden toy for both the WS (point: m = 4.57, gaze: m = 3.83) and DS (point: m = 5.04, gaze: m = 4.48) groups but noncommunicative cues were not. Binomial tests examining individual performance on communicative trials indicated that significantly more children with DS (60%) than WS (27%) found the toys at a rate greater than that expected by chance (≥10/12 trials correct). Results of a mixed ANOVA indicated significant main effects of Communicative style (p < .001, η2 = .60) and Diagnostic Group (p = .03, η2 = .08) but not Gesture (p = .15; η2 = .04). In addition, the interaction term between Communicative style and Gesture was significant (p = .02, η2 = .10), indicating a significantly greater discrepancy between performance on the two communicative style conditions for pointing than for eye gaze.

Discussion: As groups, preschoolers with WS or DS have begun to distinguish communicative intent from noncommunicative intent for non-linguistic pointing and gazing gestures. However, despite significantly lower DQs and language levels, the DS group evidenced significantly stronger pragmatic skills than the WS group. This finding provides further evidence that young children with WS have more difficulty with socio-communication than expected for CA or level of intellectual or language ability. Theoretical implications and applications will be addressed.