Duration and distance judgments of two moving objects by 1st to 6th graders

Elementary school children (N = 192) from the 1st to 6th grade (from 6 to 1 2 years old) viewed CRT displays of two cars traveling on two parallel trac ks in the same direction, for particular durations and distances. In the te mporal sessions, the participants judged which car had started earlier and had stopped earlier, or which car had rum the longer distance and which car had run faster, as well as which car had run for longer. In the spatial se ssions, the participants made spatial judgments in the same way. The result s showed that (a) it was very difficult even for the higher graders to judg e duration logically by using the knowledge structure "duration = temporal stopping point - temporal starting point", while the knowledge structure "d uration = distance / speed" seemed to be more easily activated; (b) it was very difficult for the lower graders to recognize even the premises (e.g., temporal starting and stopping points) correctly to use these knowledge str uctures; and Ic) :in the distance judgment, the knowledge structure "distan ce = duration x speed" seemed to be more easily activated than the knowledg e structure "distance spatial stopping point - spatial starting point.