The present study assesses imitative ability in chimpanzees and human children. A direct comparison of these two species was conducted in an object-manipulation task. The subjects were required to copy the model stack by stacking colored blocks in the same order as the model. Four juvenile/adolescent chimpanzees failed to copy the model stack even after a long training-period. Two adult chimpanzees eventually learned to copy the model stack of two blocks. However, they failed to copy the model of three blocks, (...) and analysis of their stacking patterns revealed that they only focused on the color of the top block in the model. Human children started to copy the model of two blocks when they were two years of age and gradually increased the number of successfully copied blocks. The results from both chimpanzees and humans are discussed in terms of the social intelligence involved in object manipulation. (shrink)

The present study assesses imitative ability in chimpanzees and human children. A direct comparison of these two species was conducted in an object-manipulation task. The subjects were required to copy the model stack by stacking colored blocks in the same order as the model. Four juvenile/adolescent chimpanzees failed to copy the model stack even after a long training-period. Two adult chimpanzees eventually learned to copy the model stack of two blocks. However, they failed to copy the model of three blocks, (...) and analysis of their stacking patterns revealed that they only focused on the color of the top block in the model. Human children started to copy the model of two blocks when they were two years of age and gradually increased the number of successfully copied blocks. The results from both chimpanzees and humans are discussed in terms of the social intelligence involved in object manipulation. (shrink)

I present my observations of combinatory manipulations by three infant chimpanzees in a series of test tasks. Common characteristics of motor patterns were observed across the tasks between both infant chimpanzees and 1-year-old infants. Based on the results, I point out that comparative approach can illuminate Thelen et al.'s arguments.

In this review, we discuss the implications of placing an infant in the supine position with respect to human cognitive development and evolution. When human infants are born, they are relatively large and immature in terms of postural and locomotor ability as compared with their closest relatives, the great apes. Hence, human mothers seemingly adopt a novel pattern of caring for their large and heavy infants, i.e., placing their infants in the supine position; this promotes face-to-face communication with their infants. (...) Moreover, infants in the supine position can interact with other nearby individuals in the same manner from an early age. In addition, the infants can also explore their own body parts and/or objects with their hands since the hands are not required to support the body and are therefore, free to move. These activities are considered to be fundamental to the early development of human social and nonsocial cognition, including knowledge of self, in the first six months after birth. Further, developmental continuity in the voluntary exploratory movements in the prenatal period to the early postnatal period is also discussed. (shrink)