Living Reference Work Entry

Encyclopedia of Evolutionary Psychological Science

pp 1-4

Date: Latest Version


  • Ivo JacobsAffiliated withLund University
  • , Mathias OsvathAffiliated withLund University Email author 


A tool used simultaneously with a second tool to increase the efficiency or effectiveness of the second tool, where the first tool (the metatool) acts directly on the second, without being used in the manufacture of the second tool. (Shumaker et al. 2011)


A chimpanzee searches the tropical forest of Bossou, Guinea, for suitable stones. She has collected oil-palm nuts, which can only be opened with tools. Having localized a large tree root, she places a nut on it and strikes it with a stone held in her hand. This is called pound or hammer tool use, which amplifies the force exerted on the nut through the use of a stone tool. However, her nut-cracking attempt fails because the wood is too soft. She therefore looks for a heavy, flat rock, which she puts on the ground to serve as an anvil. In contrast to the root, this is a tool because she directly manipulates it prior to use and is responsible for its effective orientation. Together, the hammer and anvil form a tool ...

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