The Competition Model is a psycholinguistic theory of language acquisition and sentence processing, developed by Elizabeth Bates and Brian MacWhinney (1982). The claim in MacWhinney, Bates, and Kliegl (1984) is that "the forms of natural languages are created, governed, constrained, acquired, and used in the service of communicative functions." Furthermore, the model holds that processing is based on an online competition between these communicative functions or motives. The model focuses on competition during sentence processing, crosslinguistic competition in bilingualism, and the role of competition in language acquisition. It is an emergentist theory of language acquisition and processing, serving as an alternative to strict innatist and empiricist theories. According to the Competition Model, patterns in language arise from Darwinian competition and selection on a variety of time/process scales including phylogenetic, ontogenetic, social diffusion, and synchronic scales.
The Classic Competition Model
The classic version of the model focused on competition during sentence processing, crosslinguistic competition in bilingualism, and the role of competition in language acquisition.
Sentence Processing
The Competition Model was initially proposed as a theory of cross-linguistic sentence processing. The model suggests that people interpret the meaning of a sentence by taking into account various linguistic cues contained in the sentence context, such as word order, morphology, and semantic characteristics (e.g., animacy), to compute a probabilistic value for each interpretation, eventually choosing the interpretation with the highest likelihood. According to the model, cue weights are learned inductively on the basis of the extent to which the cues are available and reliable guides to meanings in comprehension and to forms in production.
Because different languages use different cues to signal meanings, the Competition Model maintains that cue weights will differ between languages, and users of a given language will use the cue weights associated with that language, to guide their interpretation of sentences. Thus, when people learn other languages, they must learn which cues are important in which languages, in order to successfully interpret sentences in any language. The model defines a cue as an information source present in the surface structure of utterances that allows the language user to link linguistic form with meaning or function. Cues vary in their type (morphological, syntactic, prosodic, semantic, and pragmatic), availability (how often they are present), and reliability (how often they lead to the correct interpretation). Each cue has a certain level of cue validity, the joint product of availability and reliability. Cues of the same basic type, such as case-marking, animacy, or word order may have markedly different levels of validity in different languages. For example, the cue of animacy plays a minimal role in English, but a major role in Italian.
The model holds that cues both compete and cooperate during processing. Sometimes cues cooperate or converge by pointing to the same interpretation or production. Sometimes, cues compete by pointing to conflicting interpretations or productions.
Language Acquisition
The application of the model to child language acquisition focuses on the role that cue availability and reliability play in determining the order of acquisition of grammatical structures. The basic finding is that children first learn the most available cue(s) in their language. If the most available cue is not also the most reliable, then children slowly shift from depending on the available cue to depending on the more reliable cue.