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Primate Research Institute, Kyoto University
Takeshita / Poster
Development in play of building blocks in chimpanzee infants: piling up and lining up
Hideko Takeshita (The University of Shiga Prefecture)
Human infants start playing with building blocks in their 2nd year after birth. This behavior develops throughout the preschool period and seems important as one of typical form of symbolic play. There has been reported that chimpanzee infants also build a 'tower' with blocks, that is, they pile one block on the other and repeat it several times (Hayes, C., 1951; Matsuzawa, 1987). Techniques for manipulating blocks are comparable to human 1-year-old infants (Takeshita, 1994). The present longitudinal study revealed that chimpanzee infant subjects started to build a tower with blocks without any training, at around 3 years of age, and their techniques improved through several free play sessions with blocks. A human experimenter demonstrated model behaviors of piling up and lining up blocks in each session. The subjects paid much attention towards them from 3 years of age onward, however, remarkable change was observed 1 year later. The way of building blocks by the subjects after demonstration of model behaviors at 4 years of age suggested their intention of reproducing each model behavior. They piled up blocks after the demonstration of model behaviors of piling up and lined up after the model behaviors of lining up. They piled at least 7 blocks straight up. On the other hand, though they tried to reproduce model behavior of lining up, they did not succeed in lining blocks up in one row. This suggests that lining up blocks in one row is more difficult task than piling blocks straight up in 4-year-old chimpanzees, even if imitative ability emerges at this age. The result should be discussed in relation to development of visual-motor cognition in human infants and chimpanzees.
Hayes, C., 1951. The ape in our house. Harper, New York.