THE INTERACTION BETWEEN AUDITORY IMAGERY VIVIDNESS AND AUDITORY PERCEPTION, AND ITS APPLICATION TO HALLUCINATION PRONENESS by GEMMA RUTH GRAY A thesis submitted to The University of Birmingham For the degree of DOCTOR OF PHILOSOPHY School of Psychology College of Life Sciences The University of Birmingham September 2009 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties.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. Acknowledgements Firstly I’d like to thank Prof. Glyn Humphreys for his help throughout my research and for his patience and willingness to allow me room to work in my own way. I’d also like to express to Prof. Max Birchwood for his invaluable advice into the studies into hallucination proneness. Many thanks to Ali Chowdhury for his help in programming the sequence for my fMRI study, and huge thanks to Pia Rotshtein for all her help with the design and analysis of this study. Thank you for your unwavering patience with me - I’d have been entirely lost without you! I’d also like to thank Noreen O’Sullivan, Nele Demeyere and Sarah Houthuys for being wonderful office mates over the past four years and for all their support during the ups and downs of research – definitely couldn’t have got through it without you guys! Thanks also to Christine Haecker, Giles Anderson, Hayley Wright and Lara Harris for all their kind words, sympathy and for being brilliant friends throughout the time I have known them. I’d also like to express my gratitude to my family for their love and belief in me over the years, and for helping me to accomplish everything that I’ve wanted to in life. Finally, I’d like to thank my partner Tim for all his support, for keeping my feet firmly on the ground and for his insistence throughout the years that “it’ll be fine”. i Dedication For my dear Nan and Granddad – yes, I’m still getting my sums right! ii Abstract Auditory imagery is commonly used in everyday life, yet the majority of imagery research has focused on the visual domain. This thesis determined some of the mediators of auditory imagery vividness and investigated how vividness affects the interaction between imagery and perception (Chapter 2). In addition, an fMRI study investigated the neural correlates of auditory imagery and perception (Chapter 3). The final empirical chapters assessed the interaction between auditory imagery vividness and hallucination proneness, and the influence of hallucination proneness on the interaction between imagery and perception (Chapters 4, 5 and 6). Imagery vividness differs according to sound category and familiarity and is affected by cues to imagine sounds. Imagery and perception can also interact to influence the detection of sounds in noise, and are processed by partially overlapping regions of the auditory cortex. Studies into hallucination proneness revealed little differences between high and low hallucination proneness participants when detecting sounds in noise. When stimuli had an emotional connotation (i.e. auditorily presented emotional words) high and low hallucination prone participants differed only in their memory recall rate, but not in their vividness ratings, or in their sound detection performance for such words. Taken together, this thesis demonstrates that auditory imagery vividness is a robust measure that is affected by a range of cognitive factors. Vividness can influence detection of sounds in noise and has measurable affects on neural activation. These studies provide evidence for the theory that imagery and perception rely on overlapping areas of processing. The thesis also finds little association between hallucination proneness and auditory imagery vividness or sound detection performance. This suggests that factors other than auditory imagery are associated with proneness to hallucination-like experiences iii CHAPTER ONE. LITERATURE REVIEW ............................................................1 1. What is imagery? .................................................................................................2 2. Studies of auditory imagery ................................................................................6 3. Neuroanatomy of auditory system ...................................................................10 4. Neuroscientific studies: perception and imagery............................................12 4.1 Music............................................................................................................12 4.2 Speech..........................................................................................................13 4.3 Environmental Sounds.................................................................................14 5. Dissociations between sound categories...........................................................14 6. Patient studies of imagery and perception.......................................................17 7. Schizophrenia .....................................................................................................20 8. Schizotypy...........................................................................................................29 9. Hallucinations.....................................................................................................34 10. Theories of Hallucination..............................................................................39 10.1 Imagery vividness theories of hallucination ................................................40 10.2 Inner Speech Theories of Hallucination ......................................................44 10.3 Reality monitoring theories of hallucination ...............................................45 11 Emotion, schizophrenia and auditory hallucination...................................49 12 Thesis Outline.................................................................................................51 CHAPTER TWO. VIVIDNESS OF AUDITORY IMAGERY AND SOUND DETECTION..............................................................................................................57 Introduction..............................................................................................................58 Experiment 1: Effects of cue type on auditory imagery vividness ........................62 Method .....................................................................................................................62 Results......................................................................................................................66 Discussion................................................................................................................68 Experiment 2: Auditory interference effects on auditory imagery vividness ......69 Method .....................................................................................................................70 Results......................................................................................................................75 Discussion................................................................................................................80 Experiment 3: Signal Detection and Imagery Vividness........................................82 Experiment 3a. Imagery vividness and familiarity..................................................84 Method .................................................................................................................84 Results..................................................................................................................86 Discussion............................................................................................................90 iv Experiment 3b. Signal detection and imagery vividness.........................................91 Method .................................................................................................................91 Results..................................................................................................................96 Discussion..........................................................................................................104 General Discussion ................................................................................................107 CHAPTER THREE. THE NEURAL CORRELATES OF ANIMAL AND ENVIRONMENTAL SOUND PERCEPTION AND IMAGERY ......................115 Experiment 4. A sparse sampling analysis of animal and environmental sound perception and imagery...........................................................................................116 Introduction............................................................................................................116 Method ...................................................................................................................122 Results....................................................................................................................129 Discussion..............................................................................................................142 CHAPTER FOUR