THE COGNITIVE NEUROSCIENCE OF CREATIVE THINKING IN THE SCHIZOPHRENIA SPECTRUM: INDIVIDUAL DIFFERENCES, FUNCTIONAL LATERALITY AND WHITE MATTER CONNECTIVITY By Bradley S. Folley Dissertation Submitted to the Faculty of the Graduate School of Vanderbilt University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Psychology August, 2006 Nashville, Tennessee Approved: Professor Sohee Park Professor Adam W. Anderson Professor Steven D. Hollon Professor Andrew J. Tomarken to Elyse ii ACKNOWLEDGMENTS I have relied upon others’ support, generosity, and guidance to develop and complete this dissertation. Above all, my wife, Elyse, deserves my gratitude and appreciation for her eternal support, encouragement, and patience. I have appreciated and valued the unconditional support of my family and friends. I had the privilege and honor to complete this dissertation under the direction of Dr. Sohee Park. Professor Park’s energy for learning and discovery, and her steadfast support for her students have had an immeasurable impact on imbuing an appreciation for scientific research. I was fortunate, during my graduate school career, to have been guided by members of my committee and the scientific community. Their support, advice, and career mentorship have been invaluable. I am especially grateful to Drs. Adam Anderson, Laurel Brown, Peter Brugger, Susan Hespos, Steven Hollon, Wendy Kates, Andrew Tomarken, and David Zald. I would like to acknowledge my clinical supervisors including Drs. Pamela Auble, Denise Davis, Alison Kirk, Dotty Tucker, Jim Walker and those at the UCLA Semel Neuropsychiatric Institute for allowing me to learn from their thoughtful clinical acumen. I would like to give formal recognition to the members of the Developmental Psychopathology Training Grant, including Drs. Judy Garber, David Cole, and my colleagues, for giving me two years of intellectual and financial support, without which I would never have been exposed to some of the most challenging methodological and conceptual issues in clinical research. Finally, the work presented here would not have been completed without the help and support of the members of the Clinical Neuroscience Laboratory including Crystal Gibson, Mikisha Doop, F. Caroline Davis, Parzival Popof, Jejoong Kim, and Junghee Lee. This work was generously supported in part by NIMH and Vanderbilt Discovery Grants to Dr. Sohee Park and by an NIMH training grant (T32-MH18921) and NICHD Grant (P30HD15052). iii TABLE OF CONTENTS Page DEDICATION..............................................................................................................................................ii ACKNOWLEDGMENTS ...........................................................................................................................iii LIST OF TABLES......................................................................................................................................vii LIST OF FIGURES ...................................................................................................................................viii Chapter I. OVERVIEW OF THE DISSERTATION........................................................................................ 1 II. THE CREATIVITY CONSTRUCT: ITS RELATIONSHIP WITH PSYCHOPATHOLOGY AND NEUROCOGNITION............................................................................................................ 4 Creativity as a Psychological Construct ............................................................................. 5 Divergent Thinking................................................................................................ 5 Associative Hierarchies ......................................................................................... 6 Blind Variation and Selective Retention................................................................ 9 Insight, Problem-Solving and Allusive Thinking ................................................ 10 Neurobiological Bases of Creative Thinking.................................................................... 12 The Genetic Bases of Creative Ability ................................................................ 12 Heritability.............................................................................................. 13 Emergenesis............................................................................................ 14 Functional Neuroimaging Studies of Creative Thinking ..................................... 14 Psychopathology and Behavioral Investigations of Creativity ......................................... 17 Schizophrenia....................................................................................................... 17 Schizotypy ........................................................................................................... 19 Bipolar Disorder and Cyclothymia ...................................................................... 22 Summary........................................................................................................................... 24 III. INDIVIDUAL DIFFERENCES: CREATIVE THINKING ABILITY IN SCHIZOPHRENICS, SCHIZOTYPES, AND NORMAL CONTROLS.......................................................................... 26 Aims.................................................................................................................................. 29 Method.............................................................................................................................. 30 Participants .......................................................................................................... 30 Design and Material............................................................................................. 31 Procedure ............................................................................................................. 32 Measuring Creative Personality and Achievement.............................................. 33 Validity and Reliability of the Divergent Thinking Task .................................... 34 Schizotypal Personality........................................................................................ 35 Handedness and Neuropsychological Measures.................................................. 36 Results............................................................................................................................... 36 Scoring................................................................................................................. 36 Number of Singular Uses..................................................................................... 37 iv Number of Combinatory Uses ............................................................................. 38 The Effect of Intelligence .................................................................................... 38 Rate...................................................................................................................... 40 Associations with Schizotypy Factors ................................................................. 40 Associations between Divergent Thinking Scores and Handedness ................... 41 Discussion......................................................................................................................... 42 IV. HEMISPHERIC CONTRIBUTIONS TO DIVERGENT THINKING: A DIVIDED VISUAL FIELD ‘HALO’ TASK BETWEEN SCHIZOPHRENICS, SCHIZOTYPES AND NORMAL CONTROLS ...................................................................................................... 47 Aims.................................................................................................................................. 51 Method.............................................................................................................................. 52 Stimuli.................................................................................................................. 52 Verbal Stimuli......................................................................................... 52 Non-Verbal (Graphic) Stimuli ................................................................ 54 Pilot Study ........................................................................................................... 54 Subjects................................................................................................... 54 Method.................................................................................................... 54 Results..................................................................................................... 55 Divided Visual Field Experiment ........................................................................ 55 Participants ............................................................................................. 55 Tachistoscopic Presentation.................................................................... 56 Results............................................................................................................................... 58 Trial Performance ................................................................................................ 58 “Halo”.................................................................................................................. 59 Response Time..................................................................................................... 60 External Creativity..............................................................................................