Righthandness in Apes
Dr Gillian Sebestyen Forrester points out, humans and gorillas shared evolution for 23 million years, and only diverged six million years ago. This is why her recent discoveries around gorilla communications have a wider impact, and gives an insight into human language development.  Her multi-dimensional method (MDM), used in a study carried out on gorillas at Port Lympne Wild Animal Park in Kent, revealed for the first time that bias towards righthandness in apes wasn’t simply a preference for manual tasks, but may be linked to communication.

Non-verbal signals
Dr Sebestyen Forrester’s background is in neuroscience. ‘I have always been interested in the cognitive capabilities of the human brain and how they evolved to function the way that they do. This interest led me to apply my knowledge of brain anatomy and function to investigate micro patterns in non-verbal visual signals, for example manual gestures, eye gaze and facial expression, within a social context.’  Her study of great apes includes a close examination of all these different elements.

The multi-dimensional method was enabled by new technology. Two cameras were used to capture one particular ape’s every moment and interaction. ‘The rapid advances in video and data storage technologies have transformed the study of naturalistic behaviour, making it possible to record, code, and quantitatively analyse the fine detail of contextualised interactions.’

Pilot children’s study
The results of this method have proved productive. ‘One of the preliminary findings demonstrated a significant right-handed bias for actions that also involved head and mouth movements,’ explains Dr Sebestyen Forrester, ‘allowing us to link this back to our knowledge of human brain function and laterality [preference for one side of our body’s over another], providing clues as to how language may have evolved in humans.’

Not only may it give insight into how language evolved over time in humans, but also the non-verbal dimensions of language development in children. Dr Sebestyen Forrester is currently engaged in a pilot study around children and children with autism. ‘The project aims to target early communication abilities using non-verbal behavioural measures assessed by the MDM, for example eye gaze, facial expression production, laterality and physical action. The findings will then be used to construct a tool for early diagnosis of communication disorders, to facilitate intervention at an earlier point in development.’