Object play yields enormous benefits for infant development. However, little is known about natural play at home where most object interactions occur. We conducted frame-by-frame video analyses of spontaneous activity in two 2-h home visits with 13-month-old crawling infants and 13-, 18-, and 23-month-old walking infants (N = 40; 21 boys; 75%…

Infants learn nouns during object-naming events--moments when caregivers name the object of infants' play (e.g., ball as infant holds a ball). Do caregivers also label the actions of infants' play (e.g., roll as infant rolls a ball)? We investigated connections between mothers' verb inputs and infants' actions. We video-recorded 32 infant-mother…

How do infants plan and guide locomotion under challenging conditions? This experiment investigated the real-time process of visual and haptic exploration in 14-month-old infants as they decided whether and how to walk over challenging terrain--a series of bridges varying in width. Infants' direction of gaze was recorded with a head-mounted eye…

This review challenges the traditional interpretation of infants' and young children's responses to three types of potentially "fear-inducing" stimuli--snakes and spiders, heights, and strangers. The traditional account is that these stimuli are the objects of infants' earliest developing fears. We present evidence against the…

Infants require locomotor experience to behave adaptively at a drop-off. However, different experimental paradigms (visual cliff and actual gaps and slopes) have generated conflicting findings regarding what infants learn and the specificity of their learning. An actual, adjustable drop-off apparatus was used to investigate whether learning to…

Despite hundreds of studies describing infants' visual exploration of experimental stimuli, researchers know little about where infants look during everyday interactions. The current study describes the first method for studying visual behavior during natural interactions in mobile infants. Six 14-month-old infants wore a head-mounted eye-tracker…

Developmental trajectories provide the empirical foundation for theories about change processes during development. However, the ability to distinguish among alternative trajectories depends on how frequently observations are sampled. This study used real behavioral data, with real patterns of variability, to examine the effects of sampling at…

Examined how infants acquire adaptive locomotion in the novel task of going up and down slopes. Found that infants' judgments became increasingly accurate and exploration became increasingly efficient, with no transfer over the transition from crawling to walking. Infants learned to gauge their abilities on-line as they encountered each hill at…

This study examined whether 16-month-old walking infants take the material composition of a handrail into account when assessing its effectiveness as a tool to augment balance. Infants were encouraged to cross from one platform to another via bridges of various widths (10, 20, 40cm) with either a wobbly (foam or latex) or a wooden handrail…

Examined influence of child's sex on mothers' expectations about their 11-month-olds' motor development. Found that mothers of girls underestimated their performance on the novel task of crawling down steep and shallow slopes and mothers of boys overestimated their performance. Girls and boys exhibited identical levels of motor performance during…

Two experiments examined problem solving in 16-month-olds' adaptive locomotion (crossing bridges of varying width with/without handrail). Findings indicated that toddlers attempted wide bridges more than narrow ones. Attempts on narrow bridges depended on handrail presence. Toddlers had longer latencies, examined bridge/handrail more closely, and…

Used kinematic measures to compare relative contributions of growing body dimensions, age, and walking experience in walking skill development in 9- to 17-month-olds, kindergartners, and college students. Found that with increased age, size, and experience, children's steps became longer, narrower, straighter, and more consistent, reflecting a…