Choice between two discrimination tasks in chimpanzees (Pan troglodytes)

Author(s): Matsuzawa, T.

Journal/Book: Jpn Psychol Res. 1997; 39: 108 Cowley Rd, Oxford, Oxon, England OX4 1JF. Blackwell Publ Ltd. 226-235.

Abstract: The purpose of the present study was to investigate the effects of cognitive effort on a chimpanzee's choice between discrimination tasks. The tasks were of the matching-to-sample type. In Experiment 1, the chimpanzee was required to choose between a task providing a high reinforcement rate with high cognitive effort and a task providing a low reinforcement rate with low cognitive effort. Her choice depended on the reinforcement rate more than the cognitive effort. Experiments 2, 3, and 4 examined whether the kind of cognitive effort influenced the chimpanzee's choice. Experiment 2 manipulated the sample-choice relationship, so-called symmetry in the matching-to-sample tasks. Experiment 3 manipulated the number of comparison stimuli. Experiment 4 manipulated the delay interval between the sample and the comparison stimuli. In Experiments 2 and 3, the effects of the cognitive effort were confounded with those of the reinforcement rates. However, in one condition of Experiment 4, the chimpanzee preferred the simultaneous task to the delayed task, despite the lack of a significant difference in reinforcement rates between the two tasks. The present study demonstrated that the chimpanzee's choice of discrimination task depended on the cognitive effort involved, in addition to the reinforcement rate.

Note: Article Suzuki S, Kyoto Univ, Primate Res Inst, Dept Behav & Brain Sci, Sect Language & Intelligence, Inuyama, Aichi 484, JAPAN

Keyword(s): cognitive effort; discrimination task; choice behavior; chimpanzees; CLASSIFICATION

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