Number bias for the discrimination of large visual sets in infancy.

This brief report attempts to resolve the claim that infants preferentially attend to continuous variables over number [e.g. Psychol. Sci. 10 (1999) 408; Cognit. Psychol.44 (2002) 33] with the finding that when continuous variables are controlled, infants as young as 6-months of age discriminate large numerical values [e.g. Psychol. Sci. 14 (2003) 396; Cognition 89 (2003) B15; Cognition 74 (2000) B1]. In two parallel experiments, we compare 6-month-old infants' ability to discriminate number and ignore continuous variables with their ability to form a representation of a cumulative surface area and ignore number. We find that infants discriminate a 2-fold change in number but fail to discriminate a 2-fold change in cumulative surface area. The results point to a more complicated relationship between discrete and continuous dimensions than implied by previous literature.

Early understanding of the division of cognitive labor.

Two studies with 3-, 4-, and 5-year-olds (N = 104) examined whether young children can differentiate expertise in the minds of others. Study 1 revealed that all children in the sample could correctly attribute observable knowledge to familiar experts (i.e., a doctor and a car mechanic). Further, 4- and 5-year-olds could correctly attribute knowledge of underlying scientific principles to the appropriate experts. In contrast, Study 2 demonstrated that 3-, 4-, and 5-year-olds have difficulty making attributions of knowledge of scientific principles to unfamiliar experts. A computational analysis in Study 3 indicated that 4- and 5-year-olds' successes on the first two studies could not be attributed to the way in which words co-occur in discourse. Overall, these studies showed that young children have a sense of the division of cognitive labor, albeit fragile.