Patterns and trajectories in Williams Syndrome: the case of visual orientation discrimination.
In Williams Syndrome, tilted-line vision stays at a preschool level and grows only with mental age.
01Research in Context
What this study did
Palomares et al. (2011) watched how people with Williams Syndrome judge tilted lines.
They used small groups and simple computer tasks.
The team compared scores to mental age, not just birth age.
What they found
Orientation skills looked like those of typical 3- to 6-year-olds.
Skill grew with mental age, not calendar age.
The data fit a “developmental arrest” picture, not a total loss.
How this fits with other research
Spanoudis et al. (2011) used the same WS pool but tested face pictures. Autistic kids slowly shifted to mid-frequency cues, while WS kids never did. The two papers together show WS vision is stalled, not just slow.
Deruelle et al. (2006) found global configural vision was intact in WS. Melanie’s 2011 work narrows the problem to fine orientation, not all visual glue.
Spriggs et al. (2015) tracked face-configural growth over years and saw atypical curves. Their longitudinal view supports Melanie’s cross-sectional claim that WS follows its own track, not the typical one.
Why it matters
When you test a learner with WS, use mental-age norms for visual tasks. Pick teaching materials with clear, upright orientations and avoid tiny tilt differences. Target orientation drills only if mental age is under six; otherwise move to higher-level skills.
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02At a glance
03Original abstract
Williams Syndrome (WS) is a developmental disorder typified by deficits in visuospatial cognition. To understand the nature of this deficit, we characterized how people with WS perceive visual orientation, a fundamental ability related to object identification. We compared WS participants to typically developing children (3-6 years of age) and typical adults in an orientation discrimination task with four stimulus types (small circular, large circular, collinear elongated and parallel elongated gratings). We measured orientation discrimination thresholds and the proportion of orthogonal errors (i.e., mirror-image reversal errors). We evaluated how these metrics (1) are modulated by stimulus condition, and (2) vary with chronological or mental age. We found that orientation perception in WS is comparable to that of typically developing children. Orientation discrimination thresholds were better for elongated gratings than circular gratings across all participant groups. For large circular gratings, the proportion of orthogonal errors was disproportionately greater in WS participants and typically developing 3-6 year old children than in typical adults. Moreover, we found that the ability to judge orientation in WS improves with increasing mental age, but not chronological age. These results suggest that orientation discrimination in WS is developmentally arrested, as opposed to abnormal or delayed.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.01.038