PHYSICAL COGNITION IN GREAT APES: PLANNING & OBJECT COMPLIANCE Emma Carolan Tecwyn A thesis submitted to The University of Birmingham For the degree of DOCTOR OF PHILOSOPHY School of Biosciences College of Life and Environmental Sciences University of Birmingham December 2013 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. \An Orang climbs so slowly and cautiously... Even when closely pursued, his circumspection is amazing: he shakes the branches to see if they will bear him, and then bending an overhanging bough down by throwing his weight gradually along it, he makes a bridge from the tree he wishes to quit to the next." - T.H. Huxley From: Evidence as to man's place in nature (1863) Abstract It has been suggested that great ape cognitive abilities evolved in response to challenges in the physical environment related to large body size. As wild orangutans travel through the forest canopy compliant branches deform under their weight, which increases the size of gaps to be crossed and poses issues of safety and stability; yet they achieve safe and effiecient locomotion. Wild orangutans also build structurally complex nests and select branches for nest-building on the basis of their compliant properties. Both of these behaviours suggest that orangutans (1) are able to consider alternative possible actions or to plan and execute appropriate sequences of actions; and (2) possess some knowledge of object compliance (flexibility). This thesis investigated these cognitive abilities in captive great apes (orangutans and bonobos) as well as human adults and children, by presenting individuals with novel problem-solving tasks (puzzle-boxes) and novel objects (locomotor supports) and observing their behavioural responses. Attempts were made to address previous issues associated with studying physical cognition in animals, and particular attention was paid to individual differences and the role of exploration when interpreting results. Studying cognitive abilities related to wild orangutan behaviour may have implications for the evolution of cognition in great apes. i Acknowledgments First and foremost I would like to thank my supervisors Jackie Chappell and Susannah Thorpe for providing me with the incredible opportunity to work with some of our closest living relatives. I am particularly grateful to them for allowing me to develop independence and forge my own path throughout the course of my PhD, but still always being there when I needed guidance, encouragement and support. Thank you both for lots of inspiring brainstorming sessions, always getting comments on manuscripts back to me so quickly, and most of all for being approachable friendly faces. I couldn't have hoped for better supervisors. I was lucky enough to be part of two research groups: Jackie's Cognitive Adaptations Research Group and Susannah's Locomotor Ecology & Biomechanics Lab. It was great to have two quite different perspectives on my work, and I'd like to thank members of both groups { past and present { for useful discussions and practical help over the past four years: Abi, Emily, Jolyon, Julia, Kirsty, Nardie, Sam and Zoe. Special thanks to Jolyon Troscianko and Sam Coward for lending me tools to build the paddle-box; Sam's engineering prowess also enabled me to make the paddle-box ape-proof, which was no mean feat! Sam also took the time to teach me about beam biomechanics. Zoe Demery was always immensely generous with her time when I needed help, but deserves very special thanks for assisting in data collection at schools; it wouldn't have been possible (or half as fun!) without you. Abi Phillips gave me lots of tips about the orangutans in Dutch zoos with whom she had previously worked and Julia Myatt helped me identify some very bizarre orangutan positional behaviour! Interactions with researchers in other disciplines at the University of Birmingham have instilled in me of the importance of an interdisciplinary approach, and I am particularly grateful to Sarah Beck and Ian Apperly in Psychology for advice on cognitive research with children, and Aaron Sloman in Computer Sciences for challenging and inspiring discussions ii about information processing and AI. Organising an interdisciplinary workshop two years in a row with Nicola Cutting and Zoe Demery was a fantastic experience. This thesis would not have been possible without the zoos and schools that permitted me to conduct research. Many staff need to be thanked for granting permission for research, generously giving their time and sharing their knowledge, and being so enthusiastic and welcoming: Frank Rietkerk, Rudy Berends, Bianca Klein, Leo Hulsker, Cora Schout and Wilma at Apenheul Primate Park, Netherlands; Dirk-Jan van der Kolk, Jord de Meier, Olaf van Leeuwen, Monique Mul, Dorothe and Natasja at Ouwehands Dierenpark Rhenen, Netherlands; Kevin Caley, Charlotte MacDonald, John Buchan, Donna Smithson, Amber Cocks and Emma at Twycross Zoo, UK; all involved in the orangutan beam project at Chester Zoo, UK; Kate Tilley at ARK Tindal Primary Academy; Tricia Myatt at Stoneydelph Primary; and Nikki Devey at Clifton Primary. Constanze Mager-Melicharek deserves a special mention for giving me a place to stay during two separate stints at Apenheul. On a personal note, I would like to thank my parents Pam and Tex for being endlessly supportive and interested in my work; my very good friends Row and Kaat for always being there, and last but not least Paul: for keeping me sane during my time in the Netherlands and being an all round awesome person. This research was funded by the Natural Environment Research Council. iii List of publications Chapter 2 (from page 26): Tecwyn, E.C., Thorpe, S.K.S., Chappell, J. (2012) What cognitive strategies do orangutans (Pongo pygmaeus) use to solve a trial-unique puzzle-tube task incorporating multiple obstacles? Animal Cognition 15: 121-133 Chapter 3 (from page 54): Tecwyn, E.C., Thorpe, S.K.S., Chappell, J. (2013) A novel test of planning ability: great apes can plan step-by-step but not in advance of action. Behavioural Processes 100: 74-84 Chapter 4 (from page 84): Tecwyn, E.C., Thorpe, S.K.S., Chappell, J. (under review) Development of planning in 4- to 10-year-old children: reducing inhibitory demands does not improve performance. Journal of Experimental Child Psychology iv Declaration of author’s contribution Chapter 1: Entirely my own work Chapter 2: ECT designed the experiment, with input from JC and SKST. ECT collected the data, analysed the data and wrote the manuscript. JC and SKST assisted with discussion of the analysis and writing of the manuscript. Chapter 3: ECT designed the experiment, with input from JC and SKST. ECT collected the data, analysed the data and wrote the manuscript. JC and SKST assisted with discussion of the analysis and writing of the manuscript. Chapter 4: ECT designed the experiment, with input from JC and SKST. ECT collected the data, with the assistance of Zoe Demery. ECT analysed the data and wrote the manuscript. JC and SKST assisted with discussion of the analysis and writing of the manuscript. Chapter 5: The experiment was run by Emma-Louise Bryant as part of her undergraduate research project, under the supervision of ECT. The study was designed by ECT and EB with input from JC and SKST. ECT collected the data (from video footage), analysed the data and wrote the manuscript. Chapter 6: ECT designed the experiment, with input from JC and SKST. ECT collected the data, analysed the data and wrote the manuscript. JC and SKST assisted with discussion of the analysis and writing of the manuscript. Chapter 7: The study formed part of a wider project run by SKST and Sam Coward. ECT collected the data, analysed the data and wrote the manuscript. JC and SKST assisted with discussion of the analysis and writing of the manuscript. Chapter 8: Entirely my own work v Contents List of Figures xi List of Tables xii 1 General Introduction1 1.1 Animal cognition and cognitive adaptations.................2 1.2 Evolution of primate cognition........................3 1.3 Great ape cognition: driven by unique physical challenges?........5 1.4 Orangutans as a focal species.........................8 1.5 Planning in the context of physical problem-solving.............9 1.6 Compliance in the context of physical problem-solving........... 15 1.7 Studying physical cognition: considerations and challenges for researchers 18 1.7.1 Captive vs. wild studies........................ 18 1.7.2 Designing appropriate tasks...................... 20 1.7.3 Dealing with the findings: small sample sizes, negative results and individual variation.......................... 22 1.8 Aims, objectives and structure of this thesis................. 23 2 What cognitive strategies do orangutans (Pongo pygmaeus) use to solve a trial-unique puzzle-tube task incorporating multiple obstacles? 26 2.1 Introduction.................................. 28 2.2 Materials and methods............................ 34 2.2.1 Subjects and housing......................... 34 2.2.2 Apparatus: the puzzle-tube...................... 34 2.2.3 General procedure........................... 36 2.2.4 Data scoring and analysis....................... 39 2.3 Results..................................... 40 2.3.1 Initial choice of direction....................... 40 2.3.2 Directional preferences......................... 41 2.3.3 Self-correction............................. 42 2.3.4 Rule simulations............................ 42 2.3.5 GLMMs................................. 44 2.4 Discussion................................... 45 3 A novel test of planning ability: great apes can plan step-by-step but not in advance of action 54 3.1 Introduction..................................