Pointing is 'special'

Résumé En

Deixis, or pointing, is the ability to draw the viewer/listener's attention to an object, a person, a direction or an event. Pointing is involved at different stages of human communication development, in multiple modalities: first with the eyes, then with the finger, then with intonation and finally with syntax. It is ubiquitous and probably universal in human interactions. The 'special' role of index-finger pointing in language acquisition suggests that all pointing modalities may share a common cerebral network. This chapter aims at better grounding linguistic pointing in somatosensory as well as cerebral domains and at suggesting that it shares features with other pointing modalities. It is shown that manual and ocular pointings seem to recruit left posterior parietal and frontal cortices. Then vocal pointing is presented in details, for both production and perception. It is suggested that integrated multisensory representations may be needed in order to produce and perceive prosodic pointing and that these representations require the activation of associative cerebral areas. The results of a previous study support this hypothesis by showing that prosodic pointing seems to recruit a left temporo-parieto-frontal network whereas grammaticalized syntactic pointing mainly involves frontal regions. The involvement of the left parietal lobe is also apparent in our preliminary fMRI study of the perception of prosodic pointing. Finally, the exploratory results of a new study of multimodal pointing (digital, ocular, prosodic and syntactic) are presented. The common left parietal activation in ocular, digital and prosodic pointing is discussed in the framework of the link between gesture and language.