A series of studies was conducted to determine whether children's reasoning is capacity-limited and whether any such capacity, if it exists, is based on the working memory system. An N-term series (transitive inference) was used as the primary task in an interference paradigm. A concurrent short-term memory load was employed as the secondary task.…

This commentary on a paper by Douglas Detterman and others (EC 604 995), on assessing basic cognitive abilities in young adults with and without mental retardation, argues that variables measuring correct responding and variables measuring response latency or speed are two aspects of the same underlying continuum of speed and efficiency of…