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Exploration in the Rat and the Marmoset t 1 \-3-<ìt o EXPLORATION IN TFIE RAT AND TI{E MARMOSET: RELATIONSHIPS BETWEEN LEARNING AND OBJECT NOVELTY IN AN OPEN FIELD Felicity C. Forster, B.A. Hons. (Adelaide) Thesis submitted to the University of Adelaide in fulfilment of the conditions for the degree of Doctor of Philosophy. I TABLE OF CONTENTS Page SUMMARY X STATEMENT x11 ACKNOWLEDGEMENTS xüi CHAPTER 1. DESCRIBING BEHAVIOUR 1.1. Introduction 1 1.2. ExperimentalPsychology 1 1.3. Ethology J 1.4. TheEthoexperimental Approach 6 1.4.1. Complementary nature of experimental psychology and ethology 6 1.4.2. Anew paradigm: The ethoexperimental approach 8 1.4.3. Advantages of the ethoexperimental approach 10 1.5. Conclusion 72 CHAPTER 2. CONCEPTS OFEXPLORATION 2.I. Introduction t4 2.2. The Problem of Definition I4 2.3. Attempts at Defining Exploration in the Psychological Literanre 16 2.3.1. Extrinsic and intrinsic exploration t7 2.3 .2. Inspective and inquisitive exploration 18 2.3.3. Specific and diversive exploration 19 2,3.4. Difficulties with Berlyne's definitions of exploration t9 2.4. The Adaptive Significance of Exploration 2l 2.4.1. Costs of exploration 22 2.4.2. Acquisition of information about the environment 23 2.4.3. Maintenance of familiarity wittr the home range 24 ii Page CHAPTER 2 (continued) 2.4.4. I-ocation of new resources 24 2.4.5. Avoidance of predators 26 2.4.6. Learning new adaptive strategies 27 2.5. Contribution of Experimental Psychology to the Study of Exploration 29 2.5.I. Drive theories 30 2.5.2. Fea¡ theories 33 2.6 An Ethoexperimental Interpretation of Laboratory Studies of Exploration 35 2.6.1. Escape 36 2.6.2. Reaction to predation and social separation 37 2.7. Conclusion 40 CHAPTER 3. TT{E OPEN FIELD AS A METHOD FOR STUDYING Ð(PLORATION 3. 1 . Introduction 42 3.2. The Open Field 42 3.3. IndependentVariables 43 3 .3.1 . Apparatus characteristics 43 3.3.2. Testing procedures 46 3.3.3. Experimental designs 48 3.4. Dependent Variables (Measures in the Open Field) 53 3.4.1. Ambulation or activity 54 3.4.2. Pa¡ameters other than whole body movement 57 3.4.3. Physiological techniques 62 3.5. Conclusion 63 iii Page CHAPTER 4. FACTORS AFFECTING OPEN-FIELD BEHAVIOUR 4.t. Introduction 65 4.2. Subject Variables 66 4.2.1. Genetic va¡iables 66 4.2.2. Experiential variables 72 4.2.3. Interactions amongst subject variables 85 4.3. Experimental Situation: Novelty, Complexity and Learning 87 4.3.1. Novelty 88 4.3.2. Habituation of novelty 93 4.3.3. Novelty may induce fear 96 4.3.4. Complexity 100 4.3.5. Preference formoderate levels of novelty and complexity 101 4.3.6. Novelty and complexity used for behavioural enrichment 103 4.3.1. Learning 106 4.4. Conclusion tr4 CHAPTER 5 ÐGLORATION AND EXTINCTION 5.1. Introduction 115 5.2. Experiment 1: Effects of Response Generalisation and Extinction on Exploratory Behaviour in the Rat (Rattus rnnegicus) 118 5.3. Conclusion 138 lv Page CHAPTER 6. EXPLORATION IN THE CONTEXT OF TTIE BEHAVIOUR SYSTEMS APPROACH 6.1. Introduction 140 6.2. The Behaviour Systems Approach 140 6.3. Experiment 2: Exploration in the Presence of a Rolling Ball Bearing 145 6 .4 . Experiment 3: Effects of Object Novelty on Exploration in the Presence of a Rolling Ball Bearing 1,64 6.5. Conclusion t79 CHAPTER 7. COMPARATTVE STUDIES 7.I. Introduction 181 7 .2. Experiment 4: Exploration in the Rat (Ranus rnrvegicw) During Conditioning and Extinction 183 7 .3. The Marmoset as aLaboratory Animal 198 7 .3.1. The marmoset's requirements in the laboratory 200 7 .3.2. Observations of marmoset behaviour in captivity 202 7 .4. Experiment 5: Exploration in the Common Marmoset (Callithrix jacchw jacchus) During Conditioning and Extinction 204 7 .5. Conclusion 227 CHAPTER 8. HOME CAGE EXPLORATION 8. 1. Introduction 229 8.2. Experiment 6: Effects of Food Rewa¡d and Social Rewa¡d on Marmosets'Exploration in their Home Cages 230 8.3. Conclusion 258 CHAPTER 9. GENERAL DISCUSSION 260 APPENDICES 272 BIBLIOGRAPHY 290 v LIST OF TABLES Pase 5. 1. Signifrcance levels obtained for measures of exploratory behaviour (se s sio n effects) 134 6.1 Signifrcance levels obtained for measures of exploratory behaviour during conditionin g (s e s s í o n effects) 160 6.2. Signifrcance levels obtained for measures of exploratory behaviour during extinction (s es sio n effects) 161 6.3 . Significance levels obtained for measures of ball bearing- directed behaviour during extinction (group effects) t63 6.4. Signifrcance levels obtained for measures of exploratory behaviour during extinction (s e s s io n effects) t75 6.5. Significance levels obtained for measures of ball bearing- directed behaviour during extinction (session effects) 176 6.6 Significance levels obtained for measures of ball bearing- directed behaviour during conditioning (planned comparisons benveen Groups BBNO and CNO) t77 6.7 . Significance levels obtained for measures of ball bearing- directed behaviour durin g extinction (planned comparisons between Groups BBNO and CNO) 178 7 .1. Signifrcance levels obtained for measures of exploratory behaviour durin g conditionin g (s e s s ío n effects) t94 7 .2. Signifrcance levels obtained for measures of exploratory behaviour during conditionin g (group effects) 195 7 .3. Signifrcance levels obtained for measures of exploratory behaviour during extinction (group effects) 195 7 .4. Significance levels obtained for measures of exploratory behaviour during session 4 of conditioning and session 1 of extinction (sessron x group effects) 196 vl Page LIST OF TABLES (continued) 7 .5. Significance levels obtained for responses and measures of exploratory behaviour during extinction (s es sio n effects) 22t 7.6. Signifrcance levels obtained for measures of non-object- directed behaviour during extinction (session effects) 221 7 .7 . Signifrcance levels obtained for measures of exploratory behaviour during extinction (group effects) 223 7 .8. Signifrcance levels obtained for measures of exploratory behaviour during extinction (planned comparisons between Groups BF and CF) 223 7.9 Significance levels obtained for measures of exploratory and non-object-directed behaviour during extinction (group effects comparing experimental $oups with control groups) 224 7 .10. Signif,rcance levels obtained for measures of exploratory behaviour during extinction (session x group effects) 225 8.1. Signifrcance levels obtained for measures of exploratory behaviour during extinction (s e s s io n effects) 25r 8.2. Significance levels obtained for measures of exploratory behaviour durin g conditionin g (group effects) 252 8 .3 . Signifrcance levels obtained for measures of exploratory behaviour during conditionin g (group effects comparing experimental groups with control groups) 2s3 8.4. Significance levels obtained for measures of exploratory behaviour during conditioning þlanned comparisons between Groups DOOR and NO DEPRIVAION) 254 8.5. Significance levels obtained for measures of exploratory behaviour during extinction (planned comparisons between Groups DOOR and NO DEPRIVATION) 255 vii LIST OF FIGURES Page 5.1 Experimental testing chamber used in experiment 1 122 5.2 Partition showing nose-key, light and feeding trough, as employed in Group N r23 5.3. Experiment 1 novel objects t25 5.4. Event recordin g apparatus t26 s.s(r). Session means of behavioural measures in experiment 1 t32 s.s(r). Session means of behavioural measures in experiment 1 t33 6.1. Experimental testing chamber used in experiment 2, showing rolling ball bearing and four novel objects in place 148 6.2. Experiment 2 novel objects 150 6.3(r). Session means of object-directed behaviours in experiment 2 156 6.3(rr). Session means of object-directed behaviours in experiment 2 r57 6.3(rrr). Session means of ball bearing-directed behaviours in experiment 2 158 6.3(rV). Session means of ball bearing-directed behaviours in experiment 2 159 6.4. Experiment 3 novel objects used during conditioning t67 6.5. Experiment 3 novel objects used during extinction 168 6.6(r). Session means of object-directed behaviours in experiment 3 l7l 6.6(rr). Session means of object-directed behaviours in experiment 3 172 6.6(rrr). Session means of ball bearing-directed behaviours in experiment 3 173 6.6(rv). Session means of ball bearing-directed behaviours in experiment 3 174 vlll Page LIST OF FIGURES (continued) 7 .t. The laboratory rat, Rattus norvegicus t82 7.2. Experiment 4 novel objects used during conditioning 186 7.3. Experiment 4 novel objects used during extinction 187 7.4(r). Session means of behavioural measures in experiment 4 t92 7.4(rr) Session means of behavioural measures in experiment 4 193 7 .5. The common marmoset, Callithrix jacchus jacchtts r99 7.6. Experimental testing cage used in experiment 5 207 7 .7. Close-up of marmoset in testing cage, showing bar, feeder and light 208 7.8. Banana feeder used in experiment 5 209 7.e(I). Session means of responses and object-directed behaviours in experiment 5 218 7.9(rr). Session means of object-directed behaviours in experiment 5 2t9 7.e(rrD Session means of non-object-directed behaviours in experiment 5 220 8.1. Marmoset home cage, with yoghurt feeder attached to roof 236 8.2. Close-up of yoghurt feeder, showing syringe and grid for conditioned responses 237 8.3. Close-up of door in the open position 238 8.4. Experiment 6 novel objects used during conditioning 239 8.5. Experiment 6 novel objects used during extinction 240 8.6(r). Session means of responses and object-directed behaviours in experiment 6 247 8.6(rr). Session means of object-directed behaviours in experiment 6 248 8.6(rrr).
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