Investigated 5-month-olds' perception of an object whose center was occluded and whose ends were visible only in succession. Found that infants perceived the object as one connected whole when the ends underwent common motion but not when the ends were stationary. Results suggest that infants perceive object unity but not object form. (Author/BC)

Assessed infants' and adults' adjustment of hand orientation before grasping objects. Found that infants modified their hand orientation to match the long axis of an object, did not make anticipatory hand adjustments before reaching through a narrow aperture to grasp an object, and oriented their hand to be parallel with the handle of an object.…

Preterm and full-term infants were assessed on several tasks involving retrieval of a toy. When corrected for age (since conception), but not when compared by chronological age, premature infants tolerated longer delays on AB retrieval tasks than full-term infants. There were no group differences for corrected or chronological age on any other…

Used computer simulations to examine effectiveness of different criteria for measuring infant visual habituation. Found that a criterion based on fitting a second-order polynomial regression function to looking-time data produced more accurate estimation of looking times and higher power for detecting novelty effects than did the traditional…

Studied developmental changes in rhythmic motor skills by observing the hand clapping of 3- through 7-year olds. Found that a variable measuring coordination of children's arms while clapping changed from a nonconstant magnitude in younger clappers to a constant magnitude in older clappers. (BC)

Nine- through 14-year-old girls made predictions about and performed experiments involving sinking objects. Found that children initially believed that weight alone determined an object's sinking rate, older but not younger children viewed experimentation as a way of exploring object attributes other than weight, and experimentation helped…

First through fourth graders and adults judged the effect of two forces pulling simultaneously at one object by predicting the direction of the resultant force. Found that children took into account either the direction or the amount of both forces and that performance improved with age. (BC)

Collected drawings from schooled and unschooled 10- to 15-year olds in a remote region of Papua New Guinea. Found that children attending school drew only human figures. Unschooled children produced a range of drawings from scribbles through transitional forms to human figures. Some children appeared to be able to draw human figures without going…

Preschoolers, elementary school children, and adults reconstructed configurations of objects depicted on maps of empty rooms. Found that with symmetric configurations, most subjects preserved the configuration of objects, but preschoolers placed objects far from correct locations; preschoolers performed worse with asymmetric than symmetric…

Preschoolers placed stickers on maps to show locations of objects currently in view. Vantage point (eye-level versus raised), map form (plan versus oblique), and item type (floor versus furniture location) were varied. Results showed that using an oblique map first aided subsequent performance on a plan map. Subjects performed worse on floor…

Four-, 6-, and 8-year olds were shown a test picture of three related objects and two target pictures of three objects in the same or different relation. Older subjects, but not 4-year olds, identified the relationally similar target picture when the test and target also differed in dimensions of size or color saturation and in direction of size…

Results from several experiments indicated that by age 5, children distinguished animals and plants from nonliving things in terms of growth; many 5-year olds attributed growth, intake of food and water, and illness to both animals and plants; and 5-year olds responded affirmatively when asked whether plants would manifest phenomena similar to…

Results of two experiments indicated that preschoolers expected adopted babies to share physical properties, but not preferences with their biological parents; and recognized that a baby who looks like and lives with a woman but who grew inside another woman's body is not the first woman's baby. (BC)

A model of conditional reasoning predicted that children under 12 would respond correctly to questions of uncertain logical form if premises and context enabled them to access counterexamples from memory, and that children's performance with uncertain logical forms would decrease when empirically true premises are presented in a fantasy context.…

Adolescents and young adults solved reasoning problems that related to their career goals. Results indicated that subjects found goal-enhancing evidence more convincing than goal-neutral and goal-threatening evidence; statistical reasoning was more frequent on goal-threatening than goal-neutral and goal-enhancing problems; and intellectual ability…