How do age and the acquisition of independent walking relate to changes in infants' everyday experiences? We used a novel ecological momentary assessment (EMA) method to gather caregiver reports of infants' restraint, body position, and object holding via text messages sparsely sampled across multiple days of home life at 10, 11, 12, and 13 months…

Toddlers' understanding of object rotation was investigated using a multimethod approach. Participants were 44 toddlers between 22 and 38 months of age. In an eye-tracking task, they observed a shape that rotated and disappeared briefly behind an occluder. In an object-fitting task, they rotated wooden blocks and fit them through apertures.…

This research examined the development of adaptive generalization in infants' object-directed actions. Infants ages 9 and 12 months participated in an object manipulation task with stimulus objects from 2 categories that differed in shape and weight and that bore a consistent shape or weight correspondence. Weight differences between…

This study asked whether children's tendency to imitate selectively (ignore causally unnecessary actions) versus faithfully ("overimitate" causally unnecessary actions) varies across ages and social contexts. In the first experiment, 2-year-olds and 4-year-olds were randomly assigned to play 1 of 3 prior games with a demonstrator: a…

The authors examined 14- to 26-month-old infants' understanding of the spatial relationships between objects and apertures in an object manipulation task. The task was to insert objects with various cross-sections (circular, square, rectangular, ellipsoid, and triangular) into fitting apertures. A successful solution required the infant to…

Studied the early development of exploratory behavior in 99 infants of 2-5 months. Results show that there are significant changes in spontaneous multimodal exploration of a novel object between 2 and 5 months. (RJC)