1. Do Chimpanzees Use Weight to Select Hammer Tools?
- Author
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Cornelia Schrauf, Koki Fuwa, Josep Call, Satoshi Hirata, University of St Andrews. School of Psychology and Neuroscience, and University of St Andrews. Centre for Social Learning & Cognitive Evolution
- Subjects
Male ,Time Factors ,Property (programming) ,Chi square tests ,ANVILS ,WILD CHIMPANZEES ,lcsh:Medicine ,IVORY-COAST ,Monkeys ,Wildlife ,Social and Behavioral Sciences ,Choice Behavior ,law.invention ,Task (project management) ,STONE HAMMERS ,law ,Psychology ,lcsh:Science ,Problem Solving ,Multidisciplinary ,Animal Behavior ,Equipment Design ,PAN-TROGLODYTES ,Mammalogy ,Female ,Cognitive psychology ,Research Article ,Nut ,Côte d'Ivoire ,Pan troglodytes ,Animal Types ,Cote d ivoire ,Biology ,Research laboratories ,NUT-CRACKING BEHAVIOR ,Animals ,Learning ,Hammer ,Community ecology ,Chimpanzees ,Evolutionary Biology ,Tool Use Behavior ,lcsh:R ,Cognitive Psychology ,Reasoning ,lcsh:Q ,Veterinary Science ,Decision making ,Zoology ,MONKEYS CEBUS-LIBIDINOSUS - Abstract
This study was financially supported by a Japan Society for the Promotion of Science Predoc Grant (http://www.jsps.go.jp/english/e-summer/index.html) to Cornelia Schrauf. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The extent to which tool-using animals take into account relevant task parameters is poorly understood. Nut cracking is one of the most complex forms of tool use, the choice of an adequate hammer being a critical aspect in success. Several properties make a hammer suitable for nut cracking, with weight being a key factor in determining the impact of a strike; in general, the greater the weight the fewer strikes required. This study experimentally investigated whether chimpanzees are able to encode the relevance of weight as a property of hammers to crack open nuts. By presenting chimpanzees with three hammers that differed solely in weight, we assessed their ability to relate the weight of the different tools with their effectiveness and thus select the most effective one(s). Our results show that chimpanzees use weight alone in selecting tools to crack open nuts and that experience clearly affects the subjects' attentiveness to the tool properties that are relevant for the task at hand. Chimpanzees can encode the requirements that a nut-cracking tool should meet (in terms of weight) to be effective. Publisher PDF
- Published
- 2012