Perspectives on object manipulation and action grammar for percussive actions in primates

Abstract

The skill of object manipulation is a common feature of primates including humans, although there are species-typical patterns of manipulation. Object manipulation can be used as a comparative scale of cognitive development, focusing on its complexity. Nut cracking in chimpanzees has the highest hierarchical complexity of tool use reported in non-human primates. An analysis of the patterns of object manipulation in naive chimpanzees after nut-cracking demonstrations revealed the cause of difficulties in learning nut-cracking behaviour. Various types of behaviours exhibited within a nut-cracking context can be examined in terms of the application of problem-solving strategies, focusing on their basis in causal understanding or insightful intentionality. Captive chimpanzees also exhibit complex forms of combinatory manipulation, which is the precursor of tool use. A new notation system of object manipulation was invented to assess grammatical rules in manipulative actions. The notation system of action grammar enabled direct comparisons to be made between primates including humans in a variety of object-manipulation tasks, including percussive-tool use.

Extraction of honey from underground bee nests by central African chimpanzees (Pan troglodytes troglodytes) in Loango National Park, Gabon: Techniques and individual differences

“…Another approach assesses behavioral complexity by looking at the operational sequence of a technique, suggesting that complexity increases with the number of different actions required to reach a goal (Sellet, ). This method explicitly addresses the decisions made by the subject when using a tool to reach a goal, allowing for the recognition of the underlying cognitive requirements needed for success (i.e., mental organization; physical and causal understanding) (Carvalho, Cunha, Sousa, & Matsuzawa, ; Hayashi, ; Stokes & Byrne, ) and it can be coupled with a quantification of the transitions between actions (Tonooka, ). Another source of complexity is the extent of bimanual coordination of hands and feet in performing an action, since bimanual and coordinated handling patterns are considered to be associated with higher neurological complexity (Leca, Gunst, & Huffman, ).…”

Nut Cracking Tools Used by Captive Chimpanzees (Pan troglodytes) and Their Comparison with Early Stone Age Percussive Artefacts from Olduvai Gorge

“…object manipulation, transmission of tool use, and colour recognition) [32, 33]. Others studies have focused on behavioural patterns and the process of learning to crack nuts using a hammer and anvil [34–37].…”

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

“…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.…”

“…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. She also infers from her sequential analysis that the use of a wedge stone (that is, a stone used to stabilize another stone to be used as an anvil) is not an intentional behaviour of the chimpanzee but a by-product after trial and error.…”