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From play to proficiency: The ontogeny of stone-tool use in coastal-foraging long-tailed macaques (Macaca fascicularis) from a comparative perception-action perspective

Tan AWY

Journal of comparative psychology (Washington, D.C. : 1983), 2017

69 participants

Abstract

Macaques crack shellfish in coastal environments with specialized stone-hammering techniques. I provide the first examination of skill development from 866 object-manipulation and 7,400 tool-use bouts, collected over 15 months, using longitudinal analyses of infants' object manipulation (N = 7) and cross-sectional comparisons of manipulative and tool-use behavior (N = 69). I adopt a Perception-action approach, examining how the emergence of actions on objects relate to the spatial-relational and percussive challenges of tool use. Infants begin manipulating single items, particularly stones, at 1-2 months. Combining objects predominates (78%) by 1.5-2.5 years, and bouts involving food and tools but with incorrect spatial relations and action sequences prevail (73%) by 2.5-3.5 years. Placing, precedes rubbing objects on surfaces. Percussion emerges last, as disorganized striking before becoming consistent and targeted. Macaques manipulate combinations of stones and oysters, before stones, anvils, and motile shellfish, but success on either food type is only observed at 2.5-3.5 years. After competence, success rates and strike accuracy improve within 3 months on oysters and 5 months on motile shellfish. Older tool users (>4.5 years) had higher success rates, strike accuracy, strike efficiency, and tool fidelity. Macaque tool-use appears facilitated by a propensity for stone manipulation, but challenged by mastering spatial relations and percussion. I relate my findings to the…

How strong is the evidence?

Evidence Hub reads this as a cross-sectional, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 69 participants or records.

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