Molarity Versus Modularity of Cognitive Functioning?

Abstract

What is it that allows people to describe the meaning of a word, solve an analogy, complete a logic puzzle, or recall memories? His torically, cognitive and neuropsy chological researchers have sought to delineate the normative, species invariant dimensions of cognitive functioning that enable people to solve these diverse cognitive prob lems. Describing the relationship and developmental course of these processes has been a major theoret ical focus of the cognitive litera ture. Are cognitive processes re lated, or are they distinct from one another? How do they develop? These issues are addressed by the continuing molarity-versus modularity debate. A molar system is one in which a unitary, general process functions across a wide va riety of cognitive tasks. A modular system involves numerous distinct cognitive processing units, each re sponsible for certain nonoverlap ping cognitive tasks. Currently, modularity is the dominant theory in developmental cognitive psychology and neuro science (Karmiloff-Smith, 1992). According to this theory, cognitive processes are molar at birth and differentiate into distinct modular units as development proceeds. I Typically, evidence for modularity is demonstrated by showing that functioning in one domain is unaf fected by damage in another do main. For example, William's syn drome, an extremely rare genetic disorder (1 in 25,000 births), results in decreased spatial functioning but leaves verbal abilities unaf fected, and in some cases, enhanced. Environmental damage (e.g., from prenatal trauma, head injury, and strokes) has also been shown to se lectively damage certain cognitive processes, but not others. These studies demonstrate