Cognitive linguistics and psycholinguistics both deal with the relationship between language and the mind. Yet they approach this relationship from sharply different perspectives and differ in their goals, basic assumptions about the nature of language and methodologies.
Goals of Cognitive Linguistics and Psycholinguistics
While cognitive linguists study how language reflects the working of the mind, psycholinguists study how the mind handles the working of language. For instance, psycholinguistics can involve studying how language abilities are affected by strokes in different areas of the brain, while cognitive linguists would be more interested in studying whether different numbers of color words in different languages affect how speakers of these languages perceive colors.
Assumptions about the Nature of Language
Cognitive and psycholinguistics differ in their basic assumptions about the nature of language. Cognitive linguists see language as fully integrated with other cognitive functions, such as the ability to sort objects into groups or process social interactions. Thus, they assume that language can be viewed as both a reflection of these cognitive functions and a potential driver behind them. Much work in psycholinguistics, on the other hand, takes as its point of departure Noam Chomksy's view that language is an autonomous function, processed in the brain independently of other cognitive functions. As evidence for this view, psycholinguists point to the existence of people with otherwise normal cognitive functions but limited language ability and those with severe developmental disabilities but normal or better-than-normal language skills.
Methodologies in Cognitive and Psycholinguistics
Cognitive and psycholinguistics share many methodologies for gathering and analyzing linguistic data. For instance, both rely on data from recordings or transcripts of spoken language and statistical analysis of language patterns found in these materials. Both also rely on data from experiments. Some psycholinguists, however, avail themselves of another technique: asking experiment subjects directly about their perceptions about the grammaticality of sample sentences or the possible usages of certain words. Cognitive linguists, who believe that language cannot be separated from the context of its use, feel that speaker judgments about isolated language tokens cannot give an accurate picture of a speaker's knowledge and use of language.
Subfields of Cognitive Linguistics and Psycholinguistics
Cognitive linguistics encompasses many areas of linguistics and can be thought of as a general approach to linguistics rather than a distinct subfield of it: historical linguistics, language acquisition and semantics, the study of meaning, are all being researched from a cognitive perspective. Psycholinguistics covers areas such as language processing, which examines how the brain interprets spoken language and controls the production of speech, language acquisition and the study of language function in people with impaired language or intellectual abilities.