Bayley Test of Infant Development- 3rdEdition (Bayley-III)
The Bayley-III is a standardized measure to assess the cognitive, motor, language, socio-emotional, and adaptive behaviors of infants and young children between 1 and 42 months (Bayley, 2006). It is reported to have high reliability (internal consistency among domains ranges between 0.83 and 0.93) and moderate validity (confirmatory factor analysis of domain structure ranges between 0.50 and 0.79). We used the cognitive subtest of Bayley-III to match the children between the DS and TD group based on their cognitive developmental skills. The cognitive subtest assesses the problem-solving, concept formation, and memory through tasks such as completing puzzles, matching, and counting. The subtest raw scores can be converted to scaled scores and age equivalents based on the scoring norms. The age equivalents of the cognitive subtest were used to match the children across the two groups (Table 1). One child with DS did not complete the cognitive subtest due to non-compliance with the experimenter during the session; their experimental data was included in the final sample.