Feb. 17 - A propensity for right-handedness is not a uniquely human trait but one shared by great apes, according to new research by a leading cognitive psychologist. The findings cast doubt on long-held assumptions that right-handedness was connected to the emergence of language in humans. Jim Drury has more.
As distant relatives, Great Apes and humans have much in common...including a propensity for right-handedness. That's according to Dr Gillian Forrester, a senior psychology lecturer at London's University of Westminster. As part of a study into the differences between humans and other primates, Forrester and colleagues spent five years filming the hand actions of humans, gorillas, and chimpanzees. What they found came as a surprise - 90 percent of each species favoured their right hand when holding objects. Young gorillas like this had two cameras trained on them, so their behaviour could be contextualised. SOUNDBITE (English) DR GILLIAN FORRESTER, SENIOR LECTURER IN PSYCHOLOGY AT UNIVERSITY OF WESTMINSTER, SAYING: "This is a focal individual. If we want to learn about the behaviours of this individual we have a nice close-up view of this juvenile here, but we now understand that behaviour changes depending on the context, the social context, the environmental context of the animal, so we decided to add a second camera and that has a wider view, so it gives the social environment." Her results contradict the common assumption that right-handed dominance is linked to the emergence of language and is therefore unique to humans. SOUNDBITE (English) DR GILLIAN FORRESTER, SENIOR LECTURER IN PSYCHOLOGY AT UNIVERSITY OF WESTMINSTER, SAYING: "What my research has helped unravel is that human right-handedness is most likely inherited from a common human-ape ancestor and was linked to tool use well prior to the evolution of language and this is also fitting really well with archaeological evidence that now shows that humans have been right handed tool users for almost 2.5 million years but language only evolved around 100,000 years ago." Scientists have long been aware of the association between the left hemisphere specialisation for language in the human brain and human right-handedness. But now, Forrester's research raises new questions about how that association evolved.