How Minds Made Language (3): Social Interaction Mechanisms

In post 3 of this series, I will be discussing social interaction behaviours that are presumed to be socio-cognitive pre-requisites to language evolution. Specifically, I will be exploring the abilities to imitate, share joint attention, and track another's gaze.

Imitation

Imitation is the copying of another individual’s behaviour or vocalisations with the intention of achieving the same goal, whilst mimicry refers only to copying; although mimicry is important for language learning, it is imitation that is imperative, making it a language precursor.[i] Observations by Russon & Galdikas found that, after watching humans, orangutans would manoeuvre logs to form a bridge across a stream. Whilst Boesch & Boesch-Achermann observed a chimpanzee mother teaching her daughter to crack nuts more effectively by using a tool, which the daughter subsequently copied.

Primate imitation is also observed in vocalisations; chimpanzees from different troops develop similar pant hoots when living together in captivity, whilst the song of a deceased male gibbon may be taken up by his widow_.[i][ii] These examples demonstrate an ability to imitate and mimic behaviours. Within the animal kingdom, apes have the closest imitative ability to humans.[i] Imitation provided a less efficient communication system upon which natural selection could act to develop language.[iii] For words to be learnt across generations, imitation requires the imitator to recognise similarities between the actions and vocalisations of others to themselves.[i]

Joint Attention & Gaze Tracking

Another language prerequisite, joint attention, is necessary for us to communicate concepts such as objects or parts of an object to abstract notions such as love.[i] Joint attention is defined as when a child and an adult are aware that they are focusing on the same thing (Baldwin, 1995).[iv] For children to learn a word and match it to a concept, both children and caregivers often employ pointing gestures or hold up items for inspection.[i] Unlike humans, chimpanzees do not present joint attention in the wild unless calling attention to themselves and are still not able to do this as effectively as humans.

However, chimpanzees do demonstrate an ability for gaze tracking, which is important for joint attention. A study demonstrated gaze tracking in chimpanzees by engaging their attention by holding up a piece of fruit.[v] This was done when one chimpanzee (conspecific) was facing an observation tower, and another nearby chimpanzee (subject) was facing away from it.  Once the conspecific’s attention was locked on the fruit, the subject then followed their gaze towards it. Gaze tracking in chimpanzees is a prerequisite for joint attention, along with their basic Theory of Mind.[i] These characteristics set chimpanzees closer than most mammals to our own cognition; we can assume that our non-speaking primate ancestors developed language from cognition like that present in our closest primate cousins.

References

[i] Burling, R. (2005). The talking ape: How language evolved. Oxford: Oxford University Press.

[ii]Ujhelyi, M. (1998). Long-call structure in apes as a possible precursor for language. In J. R. Hurford, M. Studdert-Kennedy, C. Knight (Eds.), Approaches to the evolution of language: Social and Cognitive Bases (pp. 177-187). Cambridge, New York: Cambridge Univ. Press.

[iii] Donald, M. (1998). Mimesis and the Executive Suite: Missing links in language evolution. In J. R. Hurford, M. Studdert-Kennedy, C. Knight (Eds.), Approaches to the evolution of language: Social and Cognitive Bases (pp. 60-62). Cambridge, New York: Cambridge Univ. Press.

[iv] Akhtar, N., & Gernsbacher, M. A. (2007). Joint attention and Vocabulary Development: A Critical Look. Language and Linguistics Compass, 1(3), 195-207. doi:10.1111/j.1749-818x.2007.00014.x

[v] Tomasello, M., Call, J., & Hare, B. (1998). Five primate species follow the visual gaze of Conspecifics. Animal Behaviour, 55(4), 1063-1069. doi:10.1006/anbe.1997.0636