The manipulative complexity of Lower Paleolithic stone toolmaking.
BACKGROUND
Early stone tools provide direct evidence of human cognitive and behavioral evolution that is otherwise unavailable. Proper interpretation of these data requires a robust interpretive framework linking archaeological evidence to specific behavioral and cognitive actions.


RESULTS
Here we employ a data glove to record manual joint angles in a modern experimental toolmaker (the 4(th) author) replicating ancient tool forms in order to characterize and compare the manipulative complexity of two major Lower Paleolithic technologies (Oldowan and Acheulean). To this end we used a principled and general measure of behavioral complexity based on the statistics of joint movements.


CONCLUSIONS
This allowed us to confirm that previously observed differences in brain activation associated with Oldowan versus Acheulean technologies reflect higher-level behavior organization rather than lower-level differences in manipulative complexity. This conclusion is consistent with a scenario in which the earliest stages of human technological evolution depended on novel perceptual-motor capacities (such as the control of joint stiffness) whereas later developments increasingly relied on enhanced mechanisms for cognitive control. This further suggests possible links between toolmaking and language evolution.
Department of Bioengineering, Imperial College London, London, United Kingdom. aldo.faisal@imperial.ac.uk
Aldo
A
Faisal
Dietrich
D
Stout
Jan
J
Apel
Bruce
B
Bradley
D000818:Animals; D000885:Anthropology, Physical; D001519:Behavior / Q000502:physiology*; D005075:Biological Evolution; D003071:Cognition / Q000502:physiology; D005384:Finger Joint / Q000502:physiology; D006225:Hand / Q000502:physiology; D015186:Hominidae / Q000502:physiology* / Q000523:psychology; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology; D013933:Thumb / Q000502:physiology; D013997:Time Factors; D053001:Tool Use Behavior / Q000502:physiology*