A longstanding and fundamental debate in developmental science is whether knowledge is acquired through domain-specific or domain-general mechanisms. To date, there exists no tool to determine whether experimental data support one theoretical approach or the other. In this article, we argue that the U- and N-shaped curves found in a number of…

Research supported by a U.S. Public Health Service fellowship grant and by grant No. 01368-04 from the National Institute of Child Health and Human Development.

The question of how children represent and use comparative or partially ordered information is examined. Two experiments tested a conjecture that a common representation, a linear order, underlies the processing of all comparatives. (Author/MS)

Reviews "Levels of Cognitive Development," which presents a theory of cognitive development integrating discrimination- learning research with understanding of higher cognitive processes. Argues that strengths include its presentation of systematic research and providing continuity between past and present models. Weaknesses include…