Pictorial Primates: a Search for Iconic Abilities in Great Apes
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Pictorial Primates: A Search for Iconic Abilities in Great Apes Persson, Tomas 2008 Link to publication Citation for published version (APA): Persson, T. (2008). Pictorial Primates: A Search for Iconic Abilities in Great Apes. Cognitive Science. 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LUND UNIVERSITY PO Box 117 221 00 Lund +46 46-222 00 00 Pictorial Primates: A Search for Iconic Abilities in Great Apes PICTORIAL PRIMATES A Search for Iconic Abilities in Great Apes TOMAS PERSSON Lund University Cognitive Studies 136 Tomas Persson (2008) Pictorial Primates: A Search for Iconic Abilities in Great Apes. Lund University Cognitive Studies, 136 Copyright © Tomas Persson 2008. All rights reserved. ISBN 91-974741-9-3 ISSN 1101-8453 ISRN LUHFDA/HFKO-1019-SE Printed at Media-Tryck, Sociologen, 2008 Till mina föräldrar, och deras… Contents Preface ix Part I 1. Introduction 3 2. Child research 17 3. Cross-cultural research 35 4. The semiotic picture 45 Part II 5. Primates in picture tests 57 6. Monkeys and pigeons in indirect picture tests 83 7. Apes in indirect picture tests 103 8. Enculturants and anecdotes 131 9. Pictorial sister competencies 149 10. Producing pictures 183 Part III 11. Methods and assumptions 199 12. The Givskud studies 217 13. Bonobos and drawings 245 14. Summary and conclusions 277 References 287 Preface Pictures and other iconic media are used extensively in psychological experiments on nonhuman primate perception and conceptualisation. They are also used in interac- tion with primates in their everyday lives, and as pure entertainment. For most hu- mans, interpreting pictures is an act of imagination as much as an act of face-value recognition. Pictorial competence is thus an intriguing area for investigating minds. But in what ways do nonhuman primates understand iconic artefacts? What impli- cations do these different ways have for the conclusions we draw from those studies of perception and conceptualisation? What can pictures tell us about primate cogni- tion, and what can primates tell us about pictures? The present work has been conducted within the project “Language, Gestures and Pictures in the Perspective of Semiotic Development” (Språk, gester och bilder i ett semiotiskt utvecklingsperspektiv: SGB). The project included linguists, semioticians, and cognitive scientists at Lund University. In SGB, “development” has meant to imply both ontogenetic and phylogenetic change. Therefore I took the opportunity to continue my nonhuman primate re- search interests within this project. Primates are prime models for the study of both evolutionary change, and change in the growing individual. When it was time to settle for a research topic my point of departure was that I wanted to conduct em- pirical work with great apes in a zoo setting. Language seemed not a feasible area for investigation at the time, but nonhuman gestures were still somewhat understudied. However, I saw an even bigger lack of research effort in the area of pictures. I had just finished an observational study and now wanted to experience an experimental situation instead. Pictures thus seemed the perfect choice. Since picture understanding in animals, from a semiotic viewpoint, is indeed little explored, this thesis has taken an explorative form. Charting the land was a necessary step. Since time is always limited I simultaneously embarked on an empirical jour- ney, perhaps prematurely from a strictly scientific standpoint, but not a moment too soon from an educational one. My priority has been the study of apes, and the study of studies of apes. This is, to my knowledge, the first thesis in Sweden exclusively dedicated to non- human primate cognition. I have therefore taken the opportunity to introduce the ix field to hopefully a new readership. Occasional digresses from pictorial matters are therefore intentional. Given the novelty of this line of research also at Lund University, written material has been the main source for this thesis. It would not have been possible without the Lund University library services. Acknowledging these is therefore in order. Another major source for my development as a researcher is a group of gorillas at Givskud Zoo in Denmark. Unfortunately I do not know how to thank them, other than storing our moments in fond memory, but I can thank them symbolically throuugh thanking a second family of great apes. The bonobos I have in mind reside at the Great Ape Trust of Iowa (GATI), USA, and have likewise made an impact on me. They mighht be able to read: Some people in positions of power have been of importance for the realisation of this thesis. Director of Givskud Zoo, Richard Østerballe, my supervisor Prof. Peter Gärdenfors, Dr. Sue Savaage-Rumbaugh, and the members of the Science Circle at GATI, all deserve my gratitude for their decisions to let me work with them and animals in their care. Fruitful discussions are included in this thank you. In terms of direct help with testing I am especially grrateful to Flemming Poder and the rest of the gorilla caretakers at Givskud Zoo. At GATI I am indebted to Ta- kashi Yoshida, Jon Thompson, Ben Thompson, Elizabeth Rubert-Pugh, William Fields, and especially Dr. Sue Savagee-Rumbaugh for involvement in testing. Indirect help was given by the rest of the GATI bonobo, oranngutan, and administrative staffs. Thank you all. Ing-Marie Persson and Mathias Osvath were very helpful at Furuvik Zoo. Other influential forces have been members of the prooject SGB and participants of the SGB and the Div. of Cognitive Science at Lund University (LUCS) seminars. Colleagues at LUCS and the Department of Philosophy at Lund University have naturally been supportive at all levels of work. I am most grateful. Although I de- cided on a collective thank you, an explicit one is due to Dr. Petra Björne who di- rected my attention to a particularly crucial piece of information for the understand- ing of my own work. Funding has been received from the SGB projeect, Stiftelsen Fil. Dr. Uno Ottersteds fond, Elisabeth Rausings Minnesfond, Landshövding Per Westlings Minnesfond, and Crafoordska stiftelsen. I thank them for their generous support and interest in my work. Without it I would have been stuck at the library. Lastly, a heartfelt thank you is due to family and friends outside of work. For many years my parents have never discouraged me from my goorilla dreams. This thesis is therefore dedicated to them. x I I made no further tests, as I consider it quite obvious that results are determined simply by the technical accuracy of the photographs and the difference of the objects they represent. Anyone who may take the trouble to experiment on other chimpanzees in the same way, will be able to demonstrate effectively and exactly, by means of larger and clearer repro- ductions, that the animals recognize and differenti- ate between such photographs. As a further variation – to meet possible objections – I would suggest, in the crucial experiments, the use of pictures of an- other food – say the very popular oranges or thistles – if bananas were used in the preliminary tests. Wolfgang Köhler (1925/1957, p. 278) Chapter 1 Introduction The quote overleaf is the closing paragraph of the appendix to the second, revised, edition of Wolfgang Köhler’s classic The Mentalities of Apes, published in 1925.1 Köhler was a German Gestalt psychologist who conducted extensive experiments and observations on chimpanzees (Pan troglodytes) at the Anthropoid Station in Te- nerife in the 1910s. The studies focused on spatial problem-solving, perception and tool-use. Köhler’s work stood in opposition to especially Edward Thorndike’s asso- ciative psychology and claimed that chimpanzees were capable of solving tasks by insight, which at the time was believed to be a hallmark of human intelligence.2 To- gether with the American Robert M. Yerkes, Köhler is generally considered to be the first to thoroughly study primate behaviour in order to draw conclusions about nonhuman great ape (henceforth ape) intelligence, and its relation to human think- ing (Tomasello & Call, 1997). But simultaneously in Moscow, Russia, from 1913 to 1916, Nadezhda Ladygina- Kohts took detailed notes on an infant chimpanzee that she raised in her own home (Ladygina-Kohts, 1935/2002). She addressed many questions still studied in com- parative psychology today, and among other notable things developed the match-to- sample testing paradigm (Yerkes & Petrunkevitch, 1925). Matching-to-sample is an experimental setup where a subject is required to choose among an array of choice items the one that matches a sample item on a predefined dimension such as colour. Matching-to-sample (MTS) will play a substantial role in this thesis. Both in the literature review in Part II, and when it comes to my own empirical work in Part III. Years after the original observations, Ladygina-Kohts made comparative psychol- ogy truly comparative by making detailed comparisons between her chimpanzee data, and data gathered on her own son.