This EC-funded research project (2006-2010) explored aspects of the elementary gestures involved in human speech articulation and in human tool production and use.
The purpose of the research was to determine parameters that constrain the evolution of goal-directed action sequences made up of elementary gestures of this kind, and to define markers which can be used to assign values to these parameters in fossil and archaeological material.
In this way, a scientific tool-kit can be built to track the emergence of human speech and tool-using capacities in a rigorous manner.
Research project members also set out to re-evaluate the possibility that goal-directed action in the manipulative domain may have evolved with complexity of articulatory manoeuvres in vocal communication, reflecting shared features of neural architecture.
The main hypothesis was that syntactic language derived evolutionarily from a neural substrate for action recognition and action generation, and that the human dependence on social learning of complex tool-assisted behaviours provided the linking mechanism.
Human tool use involves an 'action grammar' that is still poorly understood, but that involves hierarchical sub-assemblies, serial order effects, and other properties of open and generative systems more commonly seen as characteristic of human language. Social learning of tool-use by observation, scaffolding, and active teaching presumes the existence of mechanisms of true imitation which entail the capacity to parse the structure and recover the meaning of observed action sequences.
If there is an evolutionary sequence from visual communication of complex gestural sequences to vocal-auditory syntactic language, then this is the most plausible route.
This leads to the hypothesis that the transition to increasingly skill-intensive lifeways during hominin evolution, and in particular the development of increasingly sophisticated tool technologies, was in and of itself a sufficient vehicle for language evolution without the need for a discrete manual gestural stage.
- European Commission FP 6 (NEST Pathfinder), Project 29065