STUDIES INTO THE COGNITIVE AND NEURAL BASIS OF CONGENITAL AMUSIA DIANA OMIGIE Goldsmiths, University of London Thesis submitted for the degree of Ph.D in Psychology University of London August 2012 1 I, Diana Omigie, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. 2 ABSTRACT The majority of humans develop a facility with music effortlessly and in the absence of explicit training. However some individuals show a distinct lack of musical ability despite seeming to have otherwise normal cognitive functioning. Based on initial studies into congenital amusia, poor pitch discrimination ability and poor pitch memory have been ascribed a central role in the condition. However, the extent to which these play a causal role in the more global difficulties associated with the disorder remains unclear. Furthermore, with the disorder increasingly being conceived of as one of awareness rather than perception, an integrated account of the disorder in which the relative importance of observed impairments are clearly delineated is becoming essential. Critically, such an account would describe congenital amusia in those terms that are commonly used to account for how musical listening ability typically develops. Further, it would be based on the results of investigations using ecologically valid stimuli and methods. In a series of four experiments, this thesis seeks to contribute towards such an account. Firstly, using behavioural methods, the state of statistical learning processes known to be necessary for the internalisation of musical regularities in typical individuals is examined. Secondly, the thesis examines the state of musical anticipatory mechanisms, a corollary of such learning, which has been shown to play a critical role in the ability to recognize and discriminate melodies. Next, using electroencephalography recordings, the neural basis of abnormal melodic pitch processing in congenital amusia is studied, while in the final chapter, a social science technique is used to investigate the extent to which amusics show normal appreciation of music in everyday life. By combining findings from current and previous studies, this thesis will contribute towards a comprehensive description of congenital amusia based on findings from a number of different levels of inquiry. 3 TABLE OF CONTENT ABSTRACT………………………………………………………………………3 LIST OF TABLES………………………………………………………..….…...7 LIST OF FIGURES……………………………………………………………....8 PUBLICATIONS ARISING FROM THESIS…………………………….……9 ACKNOWLEDGMENTS………………………………………………….…...10 CHAPTER 1: INTRODUCTION 1.1 Music cognition and disorders of music listening……………………………11 1.2 Congenital amusia……………………………………………………………15 1.2.1 Diagnosis & Incidence…………………………………………..…15 1.2.2 What is missing in music listening? ……………………………….19 1.2.3 A disorder of pitch processing? ……………………………………22 1.2.4 Music specific or music relevant? …………………………………24 1.2.5 Biological basis: Structural imaging and Twin/Family studies….…29 1.2.6 A disorder of awareness: Functional imaging studies……………...32 1.2.7 Uses and functions in everyday life: Engagement and Appreciation34 1.3 Aims of Thesis…………………………………………………………….….35 1.4 The key questions 1.4.1 Statistical learning in amusia ………………………………………37 1.4.2 Musical expectancy in amusia …………………………………..…39 1.4.3 The experience of music in everyday life in amusia ……...……….41 4 CHAPTER 2: STATISTICAL LEARNING AND ACQUISITION OF MUSICAL KNOWLEDGE 2.1 Introduction…………………………………………………………………..43 2.2 Materials and Methods……………………………………………………….47 2.3 Results………………………………………………………………………..58 2.4 Discussion……………………………………………………………………66 CHAPTER 3: DO AMUSIC INDIVIDUALS FORM MUSICAL EXPECTATIONS? 3.1 Introduction…………………………………………………………….….…71 3.2 Experiment 1 ………………………………………………………….….….79 3.2.1 Materials and Methods……………………………………………..79 3.2.2 Results……………………………………………………………...86 3.2.3 Discussion………………………………………………………….91 3.3 Experiment 2…………………………………………………………………94 3.3.1 Materials and Methods……………………………………………..94 3.3.2 Results……………………………………………………………...96 3.3.3 Discussion………………………………………………………...100 3.4 General Discussion………………………………………………………….101 CHAPTER 4: IMPAIRED PROCESSING OF MELODIC VIOLATIONS IN AMUSIA 4.1 Introduction…………………………………………………………………108 4.2 Materials and Methods……………………………………………………...113 4.3 Results………………………………………………………………………122 4.4 Discussion…………………………………………………………………..129 5 CHAPTER 5: THE EXPERIENCE OF MUSIC IN EVERYDAY LIFE: AN EXPERIENCE SAMPLING STUDY 5.1 Introduction…………………………………………………………………136 5.2 Materials and Methods……………………………………………………...142 5.3 Results………………………………………………………………………151 5.4 Discussion…………………………………………………………………..167 CHAPTER 6: SUMMARY OF FINDINGS: IMPLICATIONS, LIMITATIONS AND FUTURE DIRECTIONS 6.1 Introduction…………………………………………………………………173 6.2 Summary of findings………………………………………………………..174 6.2.1 Amusic individuals can internalise musical regularities.…174 6.2.2 Amusic individuals can form melodic expectations at an implicit level but are impaired relative to controls at an explicit level……………………………………………………………..176 6.2.3 The neural basis of impaired explicit processing may lie in impaired early mechanisms for detecting pitch deviations……..178 6.2.4 There is not a simple mapping between music appreciation and music perceptual deficits…………………………………...179 6.3 Implications of the thesis……………………………………………………180 6.4 Limitations of the current studies and proposed extensions………………...184 6.5 Closing statements…………………………………………………………..189 Appendices: Chapter 5………………………………………………….191 References………………………………………………………………192 6 LIST OF TABLES 2-1 Descriptive statistics and results of t-tests comparing amusic and control participant characteristics…………………………………………………………………………….49 2-2 Descriptive statistics and results of t-tests comparing performance of amusic and control participants on subtests of the MBEA and psychophysically measured pitch thresholds………………………………………………………………………...……….50 2-3 Results of one sample t-tests against chance performance for amusic individuals and controls across all three conditions………………………………………………………59 2-4 Results of Pearson correlations between the overall performance of both groups in the two tonal conditions and psychophysically measured pitch direction and discrimination thresholds ……………………………………………………………………….………..62 2-5 Mean hit rates, false alarm rates and d’ and c values for amusic and control participants……………………………………………………………………………….66 3-1 Descriptive statistics and results of t-tests comparing amusic and control participant characteristics…………………………………………………………………………….79 3-2 Descriptive statistics and results of t-tests comparing performance of amusic and control participants on subtests of the MBEA and psychophysically measured pitch thresholds. ……………………………………………………………………………….80 3-3 Descriptive statistics of accuracy and response times in the implicit task presented as a function of target-type, timbre and group………………………………………………88 3-4 Descriptive statistics of ratings given in the explicit task as a function of group……97 4-1 Descriptive statistics and results of t-tests comparing amusic and control participant characteristics…………………………………………………………………………...113 4-2 Descriptive statistics and results of t-tests comparing performance of amusic and control participants on subtests of the MBEA and psychophysically measured pitch thresholds………………………………………………………………………………..114 4-3 Descriptive statistics of structural features of low, mid and high IC probe notes….117 4-4 Descriptive statistics of structural features of notes in the 10 IC bins ……………..118 5-1 Descriptive statistics and results of Mann Whitney U tests comparing amusic and control participant characteristics……………………………………………………….142 5-2 Demographic details and individual MBEA subtest scores for amusic participants and performance of controls on scale subtests………………………………………………143 5-3 List of variables included in the cluster analysis …………………………………..148 7 LIST OF FIGURES 2-1 Pitch detection and pitch direction discrimination thresholds in semitones for amusic and controls participants………………………………………………………………… 51 2-2 Tone words used in language 1 and language 2 for the sub-threshold and supra- threshold tonal conditions………………………………………………………………..54 2-3 Boxplots showing performance on the linguistic, supra-threshold tonal and sub- threshold tonal conditions………………………………………………………………..61 2-4 Scatter plot showing the correlation between d’ and performance…………………..65 3-1 The musical notation of a sample melody used in the study along with its information content profile ……………………………………………………………………………82 3-2 The distribution of information contents for notes in the implicit task……………...84 3-3 Mean response times and accuracy in the implicit task……………………………...87 3-4 The distribution of information contents for notes in the explicit task………………95 3-5 Mean ratings in the explicit task……………………………………………………..98 4-1 Sample melody IC profile and note categorization…………………………………116 4-2 Grand average waveforms for amusics for low, medium, and high IC notes………123 4-3 Grand average waveforms for controls for low, medium, and high IC notes………124 4-4 Scalp maps for amusics and controls……………………………………………….125 4-5 Plot showing N1 amplitude and P2 latency as a function of IC bin………………..128 5-1 Dendrogram showing the order in which the clusters were merged………………..152 5-2 Boxplots showing performance on four key variables for cluster 1 and 2 ………...154 5-3 Boxplots showing performance on summary variables for cluster 1 and 2………...156