Countable entities: developmental changes.

The canonical countable entity for 3- and 4-year-old children is a discrete physical object. When children were asked to count labeled entities such as "forks", they counted each detached part of a fork as a separate entity. When asked to count kinds ("How many kinds of animals?") or properties ("How many colors?"), where each kind or property was exemplified by several separate objects, they included each discrete object in their count. Their counts of classes were more accurate in the absence of objects, or in the presence of a single member of each class, than in the presence of several members of each class. Young children are evidently predisposed to process discrete physical objects. Evidence is presented that, developmentally, this bias precedes learning to count. It is proposed that this discrete physical object bias facilitates mastery of counting.