Bayley Scales of Infant and Toddler Development
scales for assessing the developmental status of infants and young children ages 1 month to 42 months. Test stimuli, such as form boards, blocks, shapes, household objects (e.g., utensils), and other common items, are used to engage the child in specific tasks of increasing difficulty and elicit particular responses. The Bayley scales currently have five components. Tasks from the Mental scale are designed to evaluate such functions as perception, memory, and learning; those from the Motor scale measure gross and fine motor abilities, such as crawling, sitting, grasping, and object manipulation. The Behavior Rating scale (formerly called the Infant Behavior Record) contains detailed descriptions of specific categories of behavior that are graded on a 5-point scale. It supplements the Mental and Motor scales and provides an assessment of overall attention and arousal, orientation and engagement, emotion regulation, and motor quality. The
final two components, the Social–Emotional scale and the Adaptive Behavior scale, use questionnaires to obtain parent or caregiver perceptions of their child’s development. The Bayley scales were originally published in 1969 and subsequently revised in 1993; the most recent version is the Bayley–III, published in 2005. [developed by Nancy Bayley]