Examined in 4 experiments 2-year-olds' knowledge of solidity in search tasks. Found no evidence that 2-year-olds represented solidity and support constraints on trajectories of falling objects; two experiments included 2.5-year-olds who succeeded on search tasks. Explored implications of 2-year-olds' poor performance in light of very young…

This study was designed to determine whether modifying the task characteristics of the Stage 6 sensorimotor means-end problem (by introducing additional visual cues) aided task solution in children. Subjects were 80 children, ages 20-33 months. (CS)

This study used a set of Piagetian tasks to examine the sensorimotor skills of 40 profoundly retarded institutionalized children ranging in age from 8 to 14 years. (JMB)

A pre- to post-test design was used to evaluate the effects of rule-based instruction on rule observance, copying performance, and discrimination skill. Three ways of imparting rules (demonstration, verbal description, and combined demonstration-verbal description) were examined, and their usefulness was compared to that of copying without…

The developmental pattern of concurrent synaptogenesis in rhesus monkeys is consistent with a straightforward model of relations between brain and cognitive development. Concurrent synaptogenesis is hypothesized to lay the primary cortical foundation for a series of developmental levels in middle infancy that have been empirically documented in…

Caregiver-infant transactions with 51 premature infants were studied in naturalistic observations in the home when the infants were aged 1, 3, and 8 months. Gesell developmental schedules and a sensorimotor scale were administered at 9 months. (Author/JH)

Examined infants' ability to retrieve an object from atop a slightly larger object. Found that even 5-month-olds could retrieve objects close in size and fully contiguous with their bases when demands on reaching skill were reduced. Proposed that when they fail this task, it is because they lack the skill to reach the top object without…

Three experiments examined vision's role in infants' grasping of horizontally and vertically oriented rods. Found that infants differentially oriented their hand regardless of lighting and similar to control conditions where they could see rod and hand throughout reach. Findings suggest that infants may use current sight of object's orientation or…

An experiment demonstrating that children in Piaget's preoperational stage, who generally still cannot give conceptually correct answers to questions about rate and time, evidence an ability to imitate a given rate-time relationship demonstrated by the experimenter. (ST)

Three experiments explored 5- and 7-month-olds' intermodal coordination of proprioceptive information produced by leg movements and visual movement information specifying these same motions. Results suggested that coordination of visual and proprioceptive inputs is constrained by infants' information processing of the displays and have…

Presents evidence for four major design features of serial organization of speech arising from comparison of babbling and early speech with patterns in ten languages. Maintains that no explanation for the design features is available from Universal Grammar; except for intercyclical consonant repetition development, perceptual-motor learning seems…