Infants and Toddlers Discriminate Amount: Are They Measuring?

Abstract

Four experiments that show an early ability to encode and retain information about extent are presented. We found that infants discriminate between the heights of dowels in a habituation task. We also found that toddlers discriminate between heights on a choice task in which a target dowel is presented and removed and they then choose between the target and a foil. Until 4 years of age, however, discrimination occurs only in the presence of a perceptually salient standard. Adults do not require a perceptually present standard; they can assess extent across temporal or spatial gaps by imposing a standard (measure). The present findings indicate that infants and toddlers do not possess an adult ability to establish extent, but that they do possess a skill that provides a start point for this important intellectual achievement.