The present experiment examined whether the mental rotation ability of 9-month-old infants was related to their abilities to crawl and manually explore objects. Forty-eight 9-month-old infants were tested; half of them had been crawling for an average of 9.3 weeks. The infants were habituated to a video of a simplified Shepard-Metzler object rotating back and forth through a 240° angle around t...

Perception is believed to scale the world to reflect one's own capabilities for action-objects that are more effortful to obtain are perceived as further away. Somewhat surprisingly, perception is also influenced by observing another person attempt an action, even though others cannot directly alter one's own capabilities. It is unknown, however, whether the effects of observation reflect a sim...

A battery of 4 school-readiness tests and 16 motor tests were administered in a sample of 660 preschool children (333 male and 327 female) just about to enroll in the first grade, in order to analyze the effects of kindergarten period on school readiness and motor abilities. The sample of children was divided into six groups according to sex and duration kindergarten attendance (kindergarten pe...

We examined the contribution of executive control to individual differences in response time (RT) for naming objects and actions. Following Miyake et al., executive control was assumed to include updating, shifting, and inhibiting abilities, which were assessed using operation span, task-switching, and stop-signal tasks, respectively. Experiment 1 showed that updating ability was significantly ...