Mirror neurons and the social nature of language: The neural exploitation hypothesis

Abstract

This paper discusses the relevance of the discovery of mirror neurons in monkeys and of the mirror neuron system in humans to a neuroscientific account of primates’ social cognition and its evolution. It is proposed that mirror neurons and the functional mechanism they underpin, embodied simulation, can ground within a unitary neurophysiological explanatory framework important aspects of human social cognition. In particular, the main focus is on language, here conceived according to a neurophenomenological perspective, grounding meaning on the social experience of action. A neurophysiological hypothesis—the “neural exploitation hypothesis”—is introduced to explain how key aspects of human social cognition are underpinned by brain mechanisms originally evolved for sensorimotor integration. It is proposed that these mechanisms were later on adapted as new neurofunctional architecture for thought and language, while retaining their original functions as well. By neural exploitation, social cognition and language can be linked to the experiential domain of action.

Acknowledgements

This work was supported by MIUR (Ministero Italiano dell'Università e della Ricerca) and by the EU grants NESTCOM and DISCOS.

Notes

¹It is worth noting how long it took before a similar perspective emerged in the field of cognitive psychology (see Gibson, 1979; Glenberg, 1997; see also Gallese, 2003c)

²To what extent these levels can be c onceived as distinctly mapped in the brain is not so obvious yet.

³A discussion of the facilitatory or inhibitory nature of the specific modulation of the motor system during language processing is beyond the scope of this article, and therefore will not be dealt with here.

⁴In the present paper I exclusively focus on action. Other studies, though, also show the involvement of the sensorimotor system in the mapping of other abstract domains, like the case of time mapped onto spatial metaphors (see Boroditsky, 2000; Boroditsky & Ramscar, 2002).

⁵Establishing a relation between the motor system and the structure of language is by no means a new idea. Lashley (1951) and Marsden (1984), for example, proposed a link between syntax and the action sequencing function of the basal ganglia. A discussion of the role played in syntax by subcortical motor centers like basal ganglia and cerebellum and their thalamo-cortical connections to the premotor cortex is beyond the limited scope of this paper. However, it is perhaps worth noting that the present hypothesis is—at least partly—compatible with the procedural hypothesis of grammar proposed by Ullman (2001) according to which aspects of grammar are subserved by a frontal/basal-ganglia procedural memory system that also underlies cognitive and motor skills.