Background: Though the Down syndrome behavioural phenotype has been described as involving relative strengths in visuo-spatial processing and sociability, and relative weaknesses in verbal skills and motor planning, the early emergence of this phenotypic pattern of strengths and weaknesses has not yet been fully explored. Method: In this study, we compared the performance of eighteen 2 to 3-year-olds with Down syndrome to an MA-matched comparison group of nineteen 2 to 3-year-olds with mixed developmental disabilities, and an MA-matched comparison group of 24 children with typical development on two developmental measures: the Mullen Scales of Early Learning and the Vineland Adaptive Behaviour Scales. Results: While the specificity of the Down syndrome profile was (for the most part) not yet evident, results showed that toddlers with Down syndrome in this study did show emerging areas of relative strength and weakness similar to that which has been described in older children and young adults with Down syndrome. This pattern included relatively stronger social skills, weaker expressive language, and poor motor coordination. When this pattern of strengths and weaknesses was compared to the developmental profiles of the two comparison groups, socialisation strengths differentiated the Down syndrome group from the mixed developmental disabilities group.

For decades, researchers and practitioners have attempted to find evidence for a personality stereotype in individuals with Down syndrome that includes a pleasant, affectionate, and passive behaviour style. However, a more nuanced exploration of personality-motivation in Down syndrome reveals complexity beyond this pleasant stereotype, including reports of a less persistent motivational orientation and an over-reliance on social behaviours during cognitively-challenging tasks. It is hypothesised that the personality-motivation profile observed in individuals with Down syndrome emerges as a result of the cross-domain relations between more primary (cognitive, social-emotional) aspects of the Down syndrome behavioural phenotype. Young children with Down syndrome show a general profile of delays in the development of instrumental thinking coupled with emerging relative strengths in social-emotional functioning. If it is true that a less persistent motivational orientation emerges as a secondary phenotypic result of more primary strengths in social functioning and deficits in instrumental (means-end) thinking, it may be possible to alter the developmental trajectory of this personality-motivation profile with targeted and time-sensitive intervention. Implications for intervention planning are discussed.

People with Down syndrome (DS) are predisposed to specific areas of relative developmental strength and challenge, but it is unclear whether and how this profile affects participation in school and community settings. In this study we characterized the nature of school participation and performance of functional tasks in the school context for 26 elementary students with DS (mean age = 7.86 yr; standard deviation = 1.75). Students participated in assessments of cognitive status and language development. Their teachers completed the School Function Assessment (Coster, Deeney, Haltiwanger, & Haley, 1998) questionnaire and a standardized questionnaire on executive functioning (EF). Students demonstrated a pronounced pattern of assistance- and adaptation-related needs across various domains of school function. The strongest predictor of school function was EF skills, as reported by teachers (adjusted R² = .47, p = .003). Findings from this study should inform future intervention and school-related planning for elementary school students with DS.