Chimpanzee Mind 1995-2000 Collection of articles: Acquisition of linguistic and cognitive skills in chimpanzees and the social transfer across generations By Tetsuro MATSUZAWA, D.Sc. Primate Research Institute, Kyoto University Research report by the grant-in aid from the Ministry of Education, Science, Sports and Culture, Japan March, 2000 Foreword by Tetsuro Matsuzawa Chimpanzees are the closest relatives of humans. The genetic difference between the two species is estimated to be about 1.7 % at the DNA level, less than that between horses and zebras. Recent advances in studies of the fossil record, DNA sequences, and brain functions, all support the idea that there is a sizeable gap separating chimpanzees and monkeys, but not chimpanzees and humans. Minds and thoughts are not preserved in the fossil record. To explore the evolution of human intelligence, we must compare cognitive functions in living representatives of related species. Our studies aim to clarify linguistic and cognitive functions in chimpanzees both in the laboratory and in the wild, focusing on the mechanism of acquiring the skills and the social transfer among individuals, particularly across generations. We studied tool use, mostly concentrating on stone-tool use in the wild. We also explored the following cognitive skills shown in the laboratory: Comprehension of human speech and gestural signs, acquisition of visual symbols as a form of art)ficial language, comprehension and use of number, visual information processing including topics such as biological motion, the mechanism of extracting features in a visual search paradigm, visual illusion and perceptual completion, auditory-visual cross-modal matching, visual short-term memory, establishment of natural concepts, comprehension and use of tokens, serial recognition of video images, and so forth. The Japanese Kanji-character ")~", is derived from the shape of two persons leaning towards each other, thus lending one another support. Altruistic and mutual support may be fundamental elements of human nature. Where did such behaviors arise from in our evolutionary history? Laboratory work and field work also aimed to illuminate aspects of social propagation of cognitive skills that have been acquired at the individual level. How are knowledge and skills transferred from one individual to another? Field work in Africa has focused on tool use, especially stone-tool use and the developmental process associated with the skill. We have been carrying out a longitudinal study at Bossou, Guinea, West Africa since 1986. Bossou chimpanzees use a pair of stones to crack open oil-palm nuts. Our studies showed that there was a "critical period" between the ages of 3.5 to 5 years old for the acquisition of the skill. It took 9 to 10 years for the young chimpanzees to attain the refined level of adults. The following points have become clear through our long-term records from the field also captured on video: "careful and long-term observation by the apprentice", "strong and intrinsic motivation to imitate by the apprentice", "social tolerance of the model toward the apprentice", "neither active teaching nor moulding on the part of the model but reliably consistent presentations of proficient model behavior in front of the apprentice", etc. These motivations and attitudes provide the basis of the transfer of skills from one generation to the next, and go a long way towards explaining the persistence of cultural differences between communities. Laboratory work carried out in social contexts has contributed the following findings. A chimpanzee infant demonstrated neonatal facial imitation just like human infants. The study of imitation in a face-to-face situation revealed that chimpanzees could imitate human model actions to some extent: about 7% success in the very first trial, immediately after having observed the model's action. The imitation of simple motor patterns without the involvement of objects was a difficult task for the chimpanzees. In contrast, imitation of actions in which objects were manipulated was relatively easier. A series of "chimpanzee-chimpanzee" and "human-chimpanzee" model-apprentice experiments revealed that an apprentice chimpanzee proceeded to observe the model chimpanzee on the following two occasions: before the first attempt and/or right after his/her own failure. Apprentice chimpanzees imitated the model human when they could not solve the problem in their own way. For the future study of vertical transmission of cognitive skills between mothers and infants in a captive community, we have attempted the artificial insemination of three of our chimpanzees - with success. Three adult females, Ai, Chloe, and Pan, are expected to give birth in the year 2000. Conducting work in the laboratory carries with it a necessary sensitivity to animal welfare. We have been successful in planting a large number of trees in our outdoor compound which also has a small stream and a 15m-high set of climbing frames. Captive chimpanzees need sun, soil, stream, trees, and grass, as well as conspecifics. An innovative structure in the compound which we refer to as an "outdoor booth" serves to keep human experimenters and apparatus inside an enclosed space, while chimpanzees are free to roam the outside. In such a semi-natural situation, we now routinely conduct cognitive experiments where participation is based entirely on the free will of our chimpanzee subjects, whom we regard as our research partners. For research in the wild, sensitivity to wildlife conservation is essential. There is only a small community of about 20 chimpanzees at Bossou, living in isolation from adjacent communities. We have been conducting an extensive survey of chimpanzee habitats in the area and embarked on a large-scale tree-planting project aimed at creating a green passage or "natural corridor" connecting adjacent communities that are at present separated by cultivated fields and savannah. This report is a progress report of the long-term study of chimpanzees' intelligence at the Primate Research Institute of Kyoto University. The project, which we refer to as the "Ai-project", began in April 1978, and was subsequently extended to both laboratory and field studies of chimpanzees from a broad perspective. Without the collaboration of Tomonaga, Fujita, and other colleagues and students, and without continuous support from Prof. Kojima, the present director of PRI, I could not have continued with my efforts to study chimpanzees. In closing, I would like to mention the following three names. Prof. Kiyoko Murofushi was responsible for initiating the study of chimpanzee intelligence in Japan in the mid-1970s and thus provided the basis for the long-term research reported here. Her help and dedication drove the project forward year after year. Dr. David Premack has always been a stimulating force behind my experimental ideas ever since my spending a sabbatical leave at his lab in Pennsylvania in 1985-87. I learned a great deal from conversations with him, particularly concerning the importance of social aspects of intelligence. Finally, Dr. Jane Goodall's words have stayed with me ever since our first meeting at a symposium in Chicago in 1986 entitled "Understanding chimpanzees": to study "for the chimpanzees". Without love and respect for the chimpanzees, it does not make sense to study them. In that sense, I truly appreciate all the chimpanzees I have learned to know in the wild as well as in captivity. Please enjoy the collection of papers that follow - inspired by long-term study, they touch the hearts of our closest relatives. Thank you. Contents 1. The original articles published in English Kawai, N and Matsuzawa, T (2000) Memory span of a chimpanzee. Nature, 403, 39-40. Inoue-Nakamura, N. & Matsuzawa, T. (1997) Development of stone tool-use by wild chimpanzees(Pan troglodytes). Journal of Comparative Psychology, 111(2), 159-173. Myowa-Yamakoshi, M. & Matsuzawa, T. (1999) Factors influencing imitation of manipulatory actions in chimpanzees (Pan troglodytes). Joumal of Comparative Psychology; 113(2), 128- 136. Biro, D. & Matsuzawa, T. (1999) Numerical ordering in a chimpanzee (Pan troglodytes): Planning, executing, monitoring. Journal of Comparative Psychology. 113(2), 178-185. Fagot, J., & Tomonaga, M. (1999). Global and local processing in humans (Homo sapiens) and chimpanzees (Pan troglodytes): Use of a visual search task with compound stimuli.Journal of Comparative Psychology, 113, 3-12. Fujita, K. (1997) Perception of the Ponzo illusion by rhesus monkeys, chimpanzees, and humans: Similarity and difference in the three primate species. Perception & Psychophvsics, 59, 284-292. Tomonaga, M. (1998) Perception of shape form shading in chimpanzees (Pan troglodytes) and humans (Homo sapiens). Animal Cognition, 1, 25-35. Tomonaga, M. (1999). Visual texture segregation by the chimpanzee (Pan troglodytes). Behavioural Brain Research, 99, 209-218. Tomonaga, M. (1995) Visual search by chimpanzees (Pan): Assessment of controlling relations. Journal of the Experimental Analysis of Behavior, 63, 175-186. Tomonaga, M. (1999). Establishing functional classes in a chimpanzee (Pan troglodytes) with a two-item sequential-responding procedure. Joumal of the Experimental Analysis of Behavior, 72, 57-79. Tomonaga, M. (1995) Transfer of odd-item search performance in a chimpanzee (Pan troglodytes). Perceptual and Motor Skills, 80, 35-42. Iversen, I. & Matsuzawa, T. (1996) Visually guided drawing in the chimpanzee (Pan troglodytes). Japanese Psychological Research, 38(3), 126-135. Matsuzawa, T., Kojima, S. & Shinohara, S. (1997) Editorial:A brief note on tbe background of the study of cognition and behavior of chimpanzees by Japanese researchers. Japanese Psychological Research, 39(3),133- 139. Iversen, I. & Matsuzawa, T. (1997) Model guided line drawing in the chimpanzee (Pan troglodytes). Japanese Psychological Research, 39(3),154-181 Hashiya, K. & Kojima, S. (1997) Auditory visual intermodal matching by a chimpanzee (Pan troglodytes). Japanese Psychological Research, 39(3), 182-190. Sato, A., Kanazawa, S. & Fujita, K. (1997) Perception of object unity in a chimpanzee (Pan troglodytes). Japanese Psychological Research, 39(3),191-199. Tomonaga, M. (1997) Precuing the target location in visual searching by a chimpanzee (Pan troglodytes): Effects of precue validity. Japanese Psychological Research, 39 (3), 200-211 Tanaka, M. (1997) Formation of categories based on functions in a chimpanzee (Pan troglodytes). Japanese PsychologicalResearch, 39(3), 212-225. Suzuki. S. & Matsuzawa, T. (1997) Choice between two discrimination tasks in a chimpanzee (Pan troglodytes). Japanese Psychological Research 39(3), 226-235. Tonooka, R., Tomonaga, M. & Matsuzawa, T. (1997) Acquisition and transmission of tool making and use for drinking juice in a group of captive chimpanzees (Pan troglodytes) . Japanese Psychological Research, 39(3) 253-265 Inoue-Nakamura, N. (1997) Mirror self-recognition in nonhuman primates: A phylogenetic approach. Japanese Psychological Research, 39(3), 266-275. Hirata, S., Myowa, M., & Matsuzawa, T. (1998) Use of leaves as cushions to sit on wet groundby wild chimpanzees. American Journal Of Primatology, 44: 215-220. Fagot, J., Deruelle, C., & Tomonaga, M.(1999) Perception des dimensions globale et locale de stimuli visuels chez le primate. Primatologie, 2, 61-77. Myowa, M. (1996) Imitation of facial gestures by an infant chimpanzee. Primates, 37, 207-213. Tomonaga, M. (1999) Inversion effect in perception of human faces in a chimpanzee (Pan troglodytes). Primates, 40, 417-438. Ochiai, T. Matsuzawa, T. (1997) Planting trees in an outdoor compound of chimpanzees for an enriched environment. Proceedings of the Third International Conference on Environmental Enrichment, 355-364. October, Orlando, Florida. Matsuzawa, T (1997) The death of an infant chimpanzee at Bossou, Guinea. Pan A6ica News, 4(1):4-6. Hirata, S., Morimura, N. & Matsuzawa, T. (1998) Green passage plan (Tree-Planting Project) and environmental education using documentary videos at Elossou: A progress report. Pan Aflica News, 5(2): 18-20. Matsuzawa, T. (1998) Chimpanzees in Japan need help. Pan Africa News, 5(2):20-21. Humle, T. (1999) New record of fishing for termites (Macrotermes) by the chimpanzees of Bossou (Pan troglodytes verus), Guinea. Pan Africa News, 6(1):3-4. Matsuzawa, T., Takemoto, H., Hayakawa, S. Shimada, M. (1999) Diecke forest in Guinea. Pan Africa News, 6(1):10-11. Matsuzawa, T.; Yamakoshi, G. (1996) Comparison of chimpanzee material culture between Bossou and Nimba, West Africa. In Russon, A, Bard, K., Parker, S. (eds.), Reaching into thought'. Cambridge Univ. Press, 211-232. Matsuzawa, T. (1996) Chimpanzee intelligence in nature and in captivity: isomorphism of symbol use and tool use. In McGrew, W. et al. (eds.), Great Ape Sorieties. Cambridge Univ. Press, 196-209. Matsuzawa, T. (1998) Chimpanzee behavior: Comparative cognitive perspective. In: Greenberg, G.; Haraway, M. eds., Comparative Psychologv: A Handbook, Garland Publishers Inc., NY, 360-375. Matsuzawa, T. (1999) Communication and tool use in chimpanzees: Cultural and social contexts. In: Hauser, M.; Konishi, M. eds., The Design of Animal Communication,. Cambridge University Press, 645-671. 2. Publication list (1995-2000) [in which are listed all articles, including Japanese- language articles, published on the subject by researchers from the Primate Research Institute of Kyoto] [omitted] How to Order: This is a collection of reprints, and will be free. Send an e-mail to Dr. Tetsuro Matsuzawa requesting the reprints. His e-mail is: matsuzaw@pri.kyoto-u.ac.jp Dr. Matsuzawa also invites Primate-Science readers to visit the home page of the Primate Research Institute: http://www.pri.kyoto-u.ac.jp
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