Evolutionary psycholinguistic approach to the pragmatics of reference

Pragmatics concerns the material function of language use in the world, and thus touches on profound questions about the relationship between our cognition and the environments in which we operate. Both psycholinguistics and evolutionary linguistics have afforded greater attention to pragmatics in recent years. Though the potential of evolutionary psycholinguistics has been noted for over twenty-five years (e.g. Tooby & Cosmides, 1990; Scott-Phillips, 2010a), there has arguably been little dialogue between these two fields of study. This thesis explicitly acknowledges and investigates the adaptationist nature of functional claims in psycholinguistics, and attempts to demonstrate that psycholinguistic inquiry can provide evidence that is relevant to theories of how the cognitive architecture of linguistic communication evolved. Chapter two reviews a broad polarisation in the pragmatic and psycholinguistic literature concerning the relative roles of linguistic convention and contextual information in comprehension. It makes explicit the theoretical approaches that reliably give rise to these polar positions across scholarly domains. It goes on to map each model of comprehension to the adaptationist particulars it may entail, and in doing so illustrates two different pictures of how linguistic cognition has developed over phylogeny. The Social Adaptation Hypothesis (SAH) holds that linguistic comprehension is performed by relevance-oriented inferential mechanisms that have been selected for by a social environment (i.e. inference-using conspecifics). In particular, the SAH holds that linguistic conventions are attended to in the same way as other ostensive stimuli and contextual information, and because of their relevance to communicative interactions. The Linguistic Adaptation Hypothesis (LAH) holds that linguistic comprehension is performed by specialised cognition that has been selected for by a linguistic environment (i.e. language-using conspecifics) that was established subsequent to, and as a consequence of, the emergence of inferential communication. In particular, the LAH holds that linguistic conventions are a privileged domain of input for the comprehension system. The plausibility and congruence of both accounts with the current state of knowledge about the evolutionary picture necessitates empirical psycholinguistic evidence. The remainder of the thesis presents a series of experiments investigating referential expressions relevant to the contrastive predictions of these two adaptationist accounts. The broad question that covers all of these experiments is: how sensitive is the comprehension process to linguistic input qua linguistic input, relative to various other grades of relevant contextual information? Chapter three presents a reaction time experiment that uses speaker-specific facts about referents as referring expressions, in a conversational precedent paradigm. The experiment measures the relative sensitivity of comprehension processing to the knowledge states of speakers and the consistent use of linguistic labels, and finds greater sensitivity to linguistic labels. Chapter four introduces a further contextual variable into this paradigm, in the form of culturally copresent associations between labels and referents. The experiment presented in this chapter compares the relative sensitivity of processing to culturally copresent common ground, the privileged knowledge state of speakers, and the consistent use of linguistic labels. The results indicated greater sensitivity to linguistic labels overall, and were consistent with the LAH. Chapter five turns to visual context as a constraint on reference, and presents two pairs of experiments. Experiments 3 and 4 investigate the comprehension of referring expressions across congruous, incongruous, and abstract visual contexts. The experiments measured reaction time as subjects were prompted to identify constituent parts of tangram pictures. The results indicated a sensitivity to the visual context and the linguistic labels, and are broadly consistent with the SAH. If comprehension is characterised by particular sensitivities, we may expect speakers to produce utterances that lend themselves well to how hearers process them. Experiments 5 and 6 use a similar tangram paradigm to elicit referring expressions from speakers for component parts