The Social Cognition of Domestic Dogs (Canis familiaris) During Cross-Species Interactions with Humans Hannah Kate Worsley School of Environment and Life Sciences University of Salford Submitted in Partial Fulfilment of the Requirements of the Degree of Doctor of Philosophy September 2018 TABLE OF CONTENTS INDEX OF FIGURES ...................................................................................................................... v INDEX OF TABLES ....................................................................................................................... vi AKNOWLEDGEMENTS ............................................................................................................... vii ABSTRACT ................................................................................................................................ viii 1. INTRODUCTION....................................................................................................................... 1 1.1 ANIMAL COMMUNICATION AND SOCIAL COGNITION ..................................................... 1 1.1.1 Vocal Communication ................................................................................................ 1 1.1.2 Gestural Communication ............................................................................................ 3 1.1.3 Intentional Cross-species Communication ................................................................. 5 1.2 THE STUDY SPECIES: THE DOMESTIC DOG (Canis familiaris) ........................................... 6 1.2.1 A Brief History ............................................................................................................. 6 1.2.2 The Domestication Process: Causes, Changes and Benefits ...................................... 8 1.2.3 The Dog-Human Bond ................................................................................................ 8 1.2.4 The Attachment Bond................................................................................................. 9 1.3 DOG-HUMAN CROSS-SPECIES INTERACTIONS: A BRIEF OVERVIEW ............................... 10 1.4 CITIZEN SCIENCE ............................................................................................................. 12 1.4.1 The Evolution of Citizen Science ............................................................................... 12 1.4.2 Citizen Science: Definitions ....................................................................................... 13 1.5 OVERALL AIM AND THESIS OUTLINE ............................................................................... 14 1.5.1 Aim of the Thesis ...................................................................................................... 14 1.5.2 Thesis Structure ........................................................................................................ 15 2. RESEARCH AIMS, OBJECTIVES, METHODS AND KEY OUTCOMES ......................................... 17 2.1 AIM OF THE RESEARCH ................................................................................................... 17 2.2 METHODS ........................................................................................................................ 17 2.2.1 Objectives 1 and 2: Gestural and Vocal Communication and Social Tool Use ......... 19 2.2.2 Objectives 3, 4 & 5: Understanding Human Phrases, Causal Reasoning and Measuring Ear Temperature ............................................................................................. 22 2.3 SUMMARY OF KEY OUTCOMES ...................................................................................... 26 3. THE INTENTIONAL AND REFERENTIAL CROSS-SPECIES COMMUNICATIVE REPERTOIRE OF DOMESTIC DOGS ...................................................................................................................... 28 3.1 Intentional Vocal Communication .................................................................................. 28 3.2 Intentional Gestural Communication .............................................................................. 29 i 3.3 Referential Signalling Events........................................................................................... 30 3.4 The Present Study ........................................................................................................... 32 3.4.1 Dog-Human Communication .................................................................................... 32 3.4.2 Justifications and Aims ............................................................................................. 35 3.5 STUDY DESIGN ................................................................................................................ 36 3.5.1 Specific Procedure and Design ................................................................................. 36 3.5.2 Identification of Gestures ......................................................................................... 36 3.5.3 Intentional Gestures Analyses .................................................................................. 37 3.5.4 Referential Gestures Analyses .................................................................................. 37 3.5.5 Influence on Repertoire Size ..................................................................................... 37 3.5.6 Reliability .................................................................................................................. 38 3.6 RESULTS........................................................................................................................... 38 3.7 DISCUSSION ..................................................................................................................... 52 4. SOCIAL TOOL USE IN DOMESTIC DOGS? .............................................................................. 62 4.1 Animal Tool Using Behaviour .......................................................................................... 62 4.1.1 Classical Tool Use ..................................................................................................... 62 4.1.2 Social Tool Use .......................................................................................................... 63 4.2 The Present Study ........................................................................................................... 65 4.2.1 Social Tool Use: A Brief Review of Current Definitions ............................................. 65 4.2.2 Domestic Dogs: A Good Model for Investigating Social Tool Use ............................ 67 4.2.3 Justifications and Aims ............................................................................................. 68 4.3 STUDY DESIGN ................................................................................................................ 69 4.3.1 Specific Procedure and Design ................................................................................. 69 4.3.2 Analyses .................................................................................................................... 70 4.4 RESULTS........................................................................................................................... 71 4.5 DISCUSSION ..................................................................................................................... 78 5. DO DOGS UNDERSTAND HUMAN RECEIVE-REQUEST PHRASES?......................................... 87 5.1 Cross-Species Vocal Communication in Mammals ...................................................... 87 5.1.2 Good Boy! Do Dogs Understand What We are Saying? ........................................... 88 5.3 The Present Study ....................................................................................................... 90 5.3.1 Justification and Aims............................................................................................... 91 5.4 EXPERIMENTAL DESIGN .................................................................................................. 91 5.5 RESULTS ....................................................................................................................... 94 ii 5.6 DISCUSSION ................................................................................................................. 99 6. ARE DOMESTIC DOGS CAPABLE OF CAUSAL REASONING AND CAN EAR TEMPERATURE BE USED AS A PROXY FOR EMOTIONAL HEMISPHERIC ACTIVITY DURING BEHAVIOURAL TRIALS? ................................................................................................................................ 105 6.1 ARE DOMESTIC DOGS CAPABLE OF CAUSAL REASONING? .......................................... 105 6.1.2 A Brief Review ......................................................................................................... 105 6.1.3 Domestic Dogs and Causal Reasoning ................................................................... 107 6.2 WHAT ARE THEY THINKING? EAR TEMPERATURE AS AN INDICATOR OF HEMISPHERIC EMOTIONAL BRAIN ACTIVITY IN DOMESTIC DOGS ............................................................ 108 6.2.1 Ear Temperature and Brain Activity ....................................................................... 108 6.3 Justifications and Aims .................................................................................................. 112 6.4 EXPERIMENTAL DESIGN ............................................................................................ 113 6.5 RESULTS ....................................................................................................................