Social and socio-
Ontogeny and symbolism
Evolution of the hand and bipedality
Symbolic behaviour among humans and non-human primates incorporates the hands, and in human ancestors opportunities to use the hand for this purpose must have increased with the evolution of habitual bipedal posture and locomotion. In tracing the evolution of human symbolic behaviour it is therefore important to trace the origins of human bipedality, and to explore the progressive changes in hominid hand structure and functions that may have affected the use of the hands in communication.
A comparison of modern human hands with those of non-human primates reveals features unique to humans. Functional analyses of these unique features have shown that they are consistent with the stresses and requirements for joint movements associated with effective use of hand-held paleolithic stone tools. Hominid fossil hands from the Pliocene and Pleistocene provide some evidence of the sequence in which these features evolved. Structural adjustments to bipedal posture in the earliest hominids may have been an important correlate to developments in the hand, facilitating the use of the trunk as leverage in accelerating the hand during tool-use.
The evolutionary state of manipulatory potential of hominid hands has probably never been a limiting factor in gestural communication or in the manual creation of symbols.
A. afarensis AL-288-1 ('Lucy') under erect bipedal walking hypothesis, © Primate Evolution and Morphology Group, University of Liverpool
Some of the most interesting reconstructive work in this area is being carried out by the Primate Evolution and Morphology Group at the University of Liverpool, UK. See also their related simulated animation of the walking gait of the 1.5 million year old male teenage Nariokotome Homo erectus specimen.
ReferencesPovinelli, D. and Davis, D.R. (1994) Deifferences between chimpanzees (Pan troglodytes) and humans (Homo sapiens) in the resting state of the index finger: implications for pointing. Journal of Comparative Psychology 108: 134-139