Noam Chomsky (b. 1928) is the most influential linguist of the modern era and a key figure in the cognitive revolution. His 1957 book Syntactic Structures introduced transformational generative grammar, arguing that language is governed by abstract, hierarchical rules that generate an infinite number of sentences from a finite set of elements. His 1959 review of B.F. Skinner's Verbal Behavior was a devastating critique of the behaviorist approach to language that helped catalyze the shift from behaviorism to cognitivism in psychology.
Universal Grammar
Chomsky's central argument is that the ability to acquire language is innate — part of our biological endowment. Children acquire language too rapidly, from too impoverished input (the "poverty of the stimulus" argument), with too much structural regularity across languages, for learning to be explained by general-purpose learning mechanisms alone. Universal Grammar (UG) is the hypothesized innate endowment — a set of linguistic principles and parameters common to all human languages that constrains the space of possible grammars and enables rapid language acquisition from limited input.
Chomsky's impact on cognitive psychology extends beyond linguistics. His argument that language requires innate, domain-specific cognitive structures challenged the empiricist assumption that the mind starts as a blank slate. His distinction between competence (abstract linguistic knowledge) and performance (actual language use) mirrors the distinction between knowledge and processing that runs through cognitive psychology. His nativist position inspired nativist theories of other cognitive capacities (face perception, number sense, folk psychology) and continues to provoke debate between nativist and empiricist approaches across cognitive science.