Changes in perception-action tuning over long time scales: How children and adults perceive and act on dynamic affordances when crossing roads.

This investigation examined developmental change in how children perceive and act on dynamic affordances when crossing roads on foot. Six- to 14-year-olds and adults crossed roads with continuous cross-traffic in a large-screen, immersive pedestrian simulator. We observed change both in children's gap choices and in their ability to precisely synchronize their movement with the opening of a gap. Younger children were less discriminating than older children and adults, choosing fewer large gaps and more small gaps. Interestingly, 12-year-olds' gap choices were significantly more conservative than those of 6-, 8-, 10-, and 14-year-olds, and adults. Timing of entry behind the lead vehicle in the gap (a key measure of movement coordination) improved steadily with development, reaching adultlike levels by age 14. Coupled with their poorer timing of entry, 6-, 8-, and 10-year-olds' gap choices resulted in significantly less time to spare and more collisions than 14-year-olds and adults. Time to spare did not differ between 12-year-olds, 14-year-olds, and adults, indicating that 12-year-olds' more conservative gap choices compensated for their poorer timing of entry. The findings show that children's ability to perceive and act on dynamic affordances undergoes a prolonged period of development, and that older children appear to compensate for their poorer movement timing skills by adjusting their gap decisions to match their crossing actions. Implications for the development of perception-action tuning and road-crossing skills are discussed. (PsycINFO Database Record

Linking "what" and "where" information: How the strength of object categories influences children's memory for object locations.

We conducted three experiments to examine how the degree of category relatedness among objects in a group affects the magnitude of spatial bias in memory for their locations. Four age groups-7-, 9-, and 11-year-old children and adults-learned the locations of 20 objects marked by dots on a touchscreen monitor. After learning the object locations, participants attempted to place the objects without the aid of the dots. We compared spatial bias at test (i.e., placing objects in the same quadrant closer together than they really were) when objects within the same quadrant were strongly related versus unrelated (Experiment 1) or weakly related versus unrelated (Experiment 2). The 9-year-olds, 11-year-olds, and adults exhibited significant spatial bias when groups of objects were composed of either strongly or weakly related exemplars, but the 7-year-olds exhibited significant spatial bias only when the objects were strongly related. A third experiment revealed that the 7-year-olds exhibited only marginally significant spatial bias when objects within the same quadrant were weakly related and we cued them about the category labels beforehand. The General Discussion focuses on developmental changes in bottom-up associative processes and top-down strategic processes in memory for object locations.