Cohort model

The cohort model in psycholinguistics and neurolinguistics is a model of lexical retrieval first proposed by William Marslen-Wilson and Alan Welsh in the late 1970s. It attempts to describe how visual or auditory input (i.e., hearing or reading a word) is mapped onto a word in a hearer's lexicon. According to the model, when a person hears speech segments real-time, each speech segment "activates" every word in the lexicon that begins with that segment, and as more segments are added, more words are ruled out, until only one word is left that still matches the input.

Background information

The cohort model relies on several concepts in the theory of lexical retrieval. The lexicon is the store of words in a person's mind; it contains a person's vocabulary and is similar to a mental dictionary. A lexical entry is all the information about a word and the lexical storage is the way the items are stored for peak retrieval. Lexical access is the way that an individual accesses the information in the mental lexicon. A word's cohort is composed of all the lexical items that share an initial sequence of phonemes, and is the set of words activated by the initial phonemes of the word.

Model

The cohort model is based on the concept that auditory or visual input to the brain stimulates neurons as it enters the brain, rather than at the end of a word. This fact was demonstrated in the 1980s through experiments with speech shadowing, in which subjects listened to recordings and were instructed to repeat aloud exactly what they heard, as quickly as possible; Marslen-Wilson found that the subjects often started to repeat a word before it had finished playing, which suggested that the word in the hearer's lexicon was activated before the entire word had been heard.