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Department of Psychology, University of Wollongong, 2014 University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 2014 Conditional same/different discrimination learning in the short-beaked echidna (Tachyglossus aculeatus) Fiona Allison Russell University of Wollongong Recommended Citation Russell, Fiona Allison, Conditional same/different discrimination learning in the short-beaked echidna (Tachyglossus aculeatus), Doctor of Philosophy thesis, Department of Psychology, University of Wollongong, 2014. http://ro.uow.edu.au/theses/4057 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Department of Psychology CONDITIONAL SAME/DIFFERENT DISCRIMINATION LEARNING IN THE SHORT-BEAKED ECHIDNA (Tachyglossus aculeatus) Fiona Allison Russell (B.A., G.B.Sc.) This thesis is presented as part of the requirements for the award of the Degree of Doctor of Philosophy of the University of Wollongong 2014 Certification I, Fiona A. Russell, declare that this thesis, submitted in fulfilment of the requirements for the award of Doctor of Philosophy, in the Department of Psychology, University of Wollongong, is wholly my own work unless otherwise referenced or acknowledged. The document has not been submitted for qualifications at any other academic institution. Fiona A. Russell 25th February, 2014 i Acknowledgments I would firstly like to thank my supervisors, Dr. Darren Burke and Dr. Steven Roodenrys for their patience, expertise and support. Thanks in particular to Darren for his genuine enthusiasm for this study and his continued help after his move and to Steve for generously taking me on part way through. Thanks to the Australian Mammal division of Taronga Zoo, particularly to former managers Gary Fry and Ken de la Motte and keepers Melissa Beaven, Christi-Anne Lombe and Melinda Hunting for all their help, and to Australian Marine Mammal Research Centre director Dr. Tracey Rogers for giving me a foot in the door and lots of encouragement. A big thank you also to Paul Kitching of Taronga Zoo technical services for building the apparatus and botanic estate staff for clearing the enclosure. Last, but not least, thanks to Pitpa for being such a willing participant and helping to shed some light on one of Australia’s most fascinating animals. ii Abstract Echidnas have evolved separately from other mammalian groups for more than 200 million years and incorporate a mixture of reptilian and mammalian features. Because of these factors, they have historically been considered ‘primitive’ animals. However they have successfully adapted to a wide variety of ecological niches and their neurophysiology demonstrates a number of unusual and apparently advanced characteristics, including a relatively large brain and cerebral cortex and a comparatively massive frontal cortex. These attributes make the echidna an intrinsically compelling subject for cognitive testing. Studies of learning in the echidna have thus far been limited to only a handful of experiments. These have demonstrated that echidnas are capable of easily forming a position habit in a T-maze, show rapid improvement across a series of successive habit- reversals, are capable of learning visual discriminations and perform well in instrumental discrimination tests. This study aims to expand on these results by conducting a number of cognitive tests of the echidna’s learning abilities, specifically its’ ability to learn colour, shape and conditional discriminations, as well as the presumptively ‘high-level’ relationally based tasks of same/different and conditional same/different categorisation. This thesis also examines the ongoing debate about the mental processes involved in relational categorisation and how commonly they occur in non-human animals. In a wider context, echidnas are an ideal candidate to explore competing theories of cognitive evolution by examining whether a phylogenetically and physiologically ‘primitive’ species can perform what are generally considered to be ‘advanced’ cognitive tasks and what role ecological factors might play in the development of those abilities. Using an echidna as a subject also increases the comparatively small number of species used for cognitive testing and its’ distinct evolutionary history means these results provide a valuable comparison to the cognitive development of more commonly studied species. iii Frontispiece: Pitpa in the Taronga Zoo enclosure “Further studies of learning will undoubtedly disclose important facts about the intelligence of these remarkable animals and modify the quaint, explicitly and tacitly-held views that echidnas are little more than animated pin-cushions or, at best, glorified reptiles.” – Buchmann and Rhodes (1978, p. 144) iv Table of contents CERTIFICATION ....................................................................................................... i ACKNOWLEDGEMENTS ..................................................................................... ii ABSTRACT ..................................................................................................................... iii FRONTISPIECE .......................................................................................................... iv TABLE OF CONTENTS .......................................................................................... v LIST OF FIGURES ..................................................................................................... xv 1 INTRODUCTION ............................................................................................... 1 1.1 ANTHROPOMORPHISM ........................................................................................ 3 1.2 GENERAL PROCESS LEARNING THEORY ................................................... 3 1.2.1 ARGUMENT FOR GENERAL PROCESS LEARNING THEORY .............................. 4 1.2.1.1 Habituation ................................................................................................. 5 1.2.1.2 Associative learning ................................................................................... 5 1.2.1.2.1 Classical conditioning ........................................................................... 5 1.2.1.2.2 Operant conditioning ............................................................................ 6 1.2.1.3 Evidence for general process learning .................................................... 7 1.2.2 ARGUMENT AGAINST GENERAL PROCESS LEARNING THEORY ..................... 8 1.2.2.1 Species differences ..................................................................................... 8 1.2.2.2 Task differences .......................................................................................... 9 1.2.3 LIMITED GENERAL PROCESS THEORY ............................................................... 9 1.3 LINEAR PROGRESSION ........................................................................................ 10 1.3.1 SPECIES HIERARCHY ............................................................................................ 10 1.3.2 TASK HIERARCHY ................................................................................................. 13 1.3.2.1 Hierarchical models ................................................................................... 14 1.3.2.2 Task hierarchy as intelligence index ....................................................... 16 1.4 MOSAIC EVOLUTION ............................................................................................. 17 v 1.4.1 ADAPTIVE SPECIALISATIONS .............................................................................. 19 1.4.2 SPECIES-SPECIFIC BEHAVIOURS ......................................................................... 20 1.4.3 SPECIAL LEARNING .............................................................................................. 21 1.5 CONCLUSIONS .......................................................................................................... 21 1.6 RATIONALE ................................................................................................................ 26 2 THE SUBJECT: THE ECHIDNA (Tachyglossus aculeatus) ........ 27 2.1 BIOLOGY, EVOLUTION AND BEHAVIOUR .................................................. 28 2.1.1 TAXONOMY, CLASSIFICATION AND DISTRIBUTION ......................................... 28 2.1.2 EVOLUTION ........................................................................................................... 30 2.1.2.1 Echidnas as ‘primitive’ mammals ............................................................ 31 2.1.3 EXTERNAL FEATURES .......................................................................................... 34 2.1.4 SENSES ................................................................................................................... 35 2.1.4.1 Vision ........................................................................................................... 35 2.1.4.2 Smell ............................................................................................................. 37 2.1.4.3 Touch ............................................................................................................ 37 2.1.4.4 Hearing ........................................................................................................ 38 2.1.4.5 Electroreception ......................................................................................... 38
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