Tool use in great apes and human children : the impact of prior experience and visual feedback

Abstract

Human and primate tool use has been the focus of intensive research for many decades. Studies with non-human great apes are of special interest for the question when certain cognitive abilities evolved. This thesis investigates the role of prior experience and visual feedback in great apes’ and human children’s tool use. Prior experience with tools is normally regarded as beneficial, helping individuals to find successful strategies. Also, visual feedback and additional information about the solution of a problem can deliver crucial insight into task components. Following an introductory and a methodological chapter, Chapter 3 explores the role of visual feedback and additional information in great ape problem-solving using the Floating Peanut Task (FPT), which requires pouring water into a tube to extract an object. Findings suggest that visual feedback was necessary for success at first, but later became redundant, and end-state information (seeing a water-filled tube) helped some individuals independently.

As a downside of experience, familiar strategies may restrict the analysis of novel problems. Most interestingly, prior use of a tool can discourage using it with a novel function (functional fixedness effect). Chapter 4 investigates functional fixedness in 6- to 8-year-old children using the FPT, focusing on how prior tool use and task presentation predict success. Findings suggest low success rates overall and no effect of experience; however, greater tool salience increased success. Chapter 5 investigates functional fixedness in great apes, varying their experience with three tools to be used each with a novel function. Prior experience lowered success and increased latency on novel problems, and prior use as a food item kept apes from using a bread stick as a raking tool. Chapter 6 discusses the overall findings in terms of the evolutionary origins of the negative impact of prior experience with tools, object representations, and learning mechanisms.