How similar are nut-cracking and stone-flaking? A functional approach to percussive technology

Abstract

Various authors have suggested similarities between tool use in early hominins and chimpanzees. This has been particularly evident in studies of nut-cracking which is considered to be the most complex skill exhibited by wild apes, and has also been interpreted as a precursor of more complex stone-flaking abilities. It has been argued that there is no major qualitative difference between what the chimpanzee does when he cracks a nut and what early hominins did when they detached a flake from a core. In this paper, similarities and differences between skills involved in stone-flaking and nut-cracking are explored through an experimental protocol with human subjects performing both tasks. We suggest that a ‘functional’ approach to percussive action, based on the distinction between functional parameters that characterize each task and parameters that characterize the agent's actions and movements, is a fruitful method for understanding those constraints which need to be mastered to perform each task successfully, and subsequently, the nature of skill involved in both tasks.

Nut‐cracking behaviour in wild‐born, rehabilitated bonobos (Pan paniscus): a comprehensive study of hand‐preference, hand grips and efficiency

“…This grip was used across different hammerstones, regardless of size, shape, thickness or weight, and appears to be the most effective grip for nut-cracking. A similar grip was also shown to be the most effective in humans during nut-cracking [Bril and Dietrich, 2015]. For larger stones, the thumb was normally held in opposition (Fig.…”

Evidence in hand: recent discoveries and the early evolution of human manual manipulation

“…These tools are 700 000 years older than earliest Oldowan technology (2.6 Ma [63]) and over 500 000 years older than the earliest possible fossil evidence of Homo (2.8 Ma [105]). Their techno-morphology suggests they were made using arm and hand motions that are most similar to the hammeron-anvil technique used by chimpanzees during nut-cracking (but likely requiring greater cognitive ability [106]; see also [107]), rather than the free-hand knapping of the Oldowan [13]. The inferred knapping technique suggests a substantial rstb.royalsocietypublishing.org Phil.…”

Percussive technology in human evolution: an introduction to a comparative approach in fossil and living primates

“…Her results suggest that the arboreal locomotion of early hominins could have been accompanied by anatomical adaptations to tool use, hence triggering further evolutionary changes towards improved dexterity. Manual dexterity is also studied by Bril et al [33], who approach the subject from an experimental perspective; they compare functional requirements of nut-cracking and stone flaking in modern humans, and highlight the substantial differences in the required degree of manual dexterity between the two activities. Bril et al [33] also recognize the relevance of cognitive parameters involved in percussive technology, which is precisely the focus of the paper by Hayashi [34].…”

“…Manual dexterity is also studied by Bril et al [33], who approach the subject from an experimental perspective; they compare functional requirements of nut-cracking and stone flaking in modern humans, and highlight the substantial differences in the required degree of manual dexterity between the two activities. Bril et al [33] also recognize the relevance of cognitive parameters involved in percussive technology, which is precisely the focus of the paper by Hayashi [34]. Hayashi [34] emphasizes the necessity for sequential analysis of actions involved in nut-cracking, instead of action-based analysis, to understand behavioural strategies adopted by chimpanzees.…”