Psycholinguistics, or psychology of language, is the study of psychological states and mental activity that are associated with the use of language. Psycholinguistics is a cross-disciplinary field and draws upon ideas and findings from areas including cognitive psychology, theoretical linguistics, phonetics, discourse analysis, neurology, computer science, semantics and education. Cognitive psychology, in particular, provides many of the basic tenets and research methods of psycholinguistics.
The field studies the way in which operations of the mind make language possible. Specifically, it explores the cognitive processes that underline the use, storage and acquisition of language. It takes into account affective and contextual factors only as far as their impact on performance is concerned. Psycholinguistic's main goal is the identification of general patterns of behavior across language users, which might reflect the capabilities and biases of the human brain or the processing requirements of the language under investigation. A perennial subject of debate among psycholinguists is whether language is a function of thinking or thought a function of the use of language.
Psycholinguistics did not become a separate subject until the beginning of the 1960s, when behaviorist approaches to the study of the mind were abandoned. However, interest in related topics dates back to diaries recording the language development of children in the eighteenth century as well as to research on the location of the language in the brain in the nineteenth century. The introspective methods of Wilhelm Wundt's psychology laboratory, which was established in 1879 and Francis Galton's work on work associations are also related to this field.
Psycholinguists working in the field of language processing seek to identify the processes that underline the two productive skills (speaking and writing) and the two receptive ones (listening and reading). Some language processing research relies on observational data or introspective methods such as a verbal report. However, the experimental approach is the most favored one. Parametric data in the form of, for example, the reaction times involved in carrying out a small-scale task, such as distinguishing actual words from non-words, are preferred. A long-term area of interest has also been the way in which vocabulary is stored in the language user's mental lexicon. Over time, interest in storage has been extended to the ways in which sounds and grammar are represented in the mind.
Developmental psycholinguistics study language acquisition. There are two broad traditions of research in this area. A theory-driven one adopts the assumption that linguistic descriptions of grammar correspond to actual mental processes. This line of enquiry draws especially on accounts by Noam Chomsky. The second tradition is data-driven and studies samples of child language, using the analytical tools provided by mainstream linguists and discourse analysis. Language acquisitions studies favor the research method that consists of longitudinal observation based upon diaries or recordings, while sometimes interviews with children are also employed by researchers in order to elicit specific linguistic items.
A different area of acquisition research studies the way in which learners master a foreign language. Psycholinguistic theory provides a framework for studying the cognitive processes that lead to expertise in the target language as well as the additional cognitive demands imposed upon the user of a second language by unfamiliar phonology, lexis and syntax.
Technological advances, particularly the advent of brain imaging equipment, has assisted all areas of psycholinguistics. Thanks to such equipment, researchers can monitor brain activity while a subject is undertaking a language processing task. The purpose of such research is to discover which parts of the brain are engaged and at which stages.
A number of areas of enquiry are loosely associated with the study of language in the brain. One explores the question of whether language is a form of communication peculiar to human beings. Another area studies the question of how language evolved. Both areas consider the possibility that in addition to the evolution of the human vocal apparatus, language owes its existence to the unique configuration of the human brain.
Another area of psycholinguistics contributes to an understanding of language impairments, both developmental impairment and impairment that is acquired as a result of illness or accident. Psycholinguists study the processes that contribute to dyslexia and dysgraphia, with aphasic symptoms produced by strokes and with disorders of speech. This research not only contributes to the work of clinicians but also sheds contrastive light on normal language processing.