ON THE LATENT STRUCTURE OF COGNITIVE MALINGERING: A MULTIVARIATE TAXOMETRIC ANALYSIS By OTTO PEDRAZA A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2004 Copyright 2004 by Otto Pedraza TABLE OF CONTENTS page LIST OF TABLES............................................................................................................. vi LIST OF FIGURES .......................................................................................................... vii ABSTRACT..................................................................................................................... viii CHAPTER 1 INTRODUCTION ........................................................................................................1 Cognitive Malingering..................................................................................................4 Research Methodology in Cognitive Malingering .......................................................6 Case-Study Designs...............................................................................................7 Simulation Designs..............................................................................................10 Known-Groups Designs ......................................................................................11 Differential Prevalence Designs..........................................................................14 Floor Effect..........................................................................................................15 Performance Curve..............................................................................................16 Magnitude of Error..............................................................................................18 Symptom Validity Testing ..................................................................................19 Atypical Presentation...........................................................................................23 Psychological Sequelae .......................................................................................26 Additional Factors Involved in Cognitive Malingering Research..............................26 Instructions ..........................................................................................................27 Incentives.............................................................................................................28 Coaching..............................................................................................................29 Warning ...............................................................................................................30 Order Effects .......................................................................................................30 Standard versus Specific Measures .....................................................................31 Nature of the Problem: The Malingering Construct...................................................32 Latent Structure Analysis and Multivariate Taxometrics...........................................36 Maximum Covariance .........................................................................................39 Mean above Minus below a Cut..........................................................................41 Maximum Eigenvalue .........................................................................................42 Intellectual Functioning..............................................................................................43 Statement of the Problem............................................................................................44 iii Goals and Hypotheses.................................................................................................46 Hypothesis 1 ........................................................................................................47 Hypothesis 2 ........................................................................................................47 Hypothesis 3 ........................................................................................................48 Hypothesis 4 ........................................................................................................48 2 METHOD ...................................................................................................................50 Participants .................................................................................................................50 Materials .....................................................................................................................51 Informed Consent ................................................................................................51 Questionnaire.......................................................................................................51 Instructions to Analogue Malingering Participants.............................................51 Quiz .....................................................................................................................52 Instructions to Control Participants.....................................................................52 Wechsler Abbreviated Scale of Intelligence .......................................................52 Malingering Measures.........................................................................................52 Clinical Measures ................................................................................................53 Manipulation Check ............................................................................................54 Strategies Questionnaire......................................................................................54 Debriefing Form ..................................................................................................54 Procedure ....................................................................................................................54 Statistical Analyses.....................................................................................................55 Hypothesis 1 ........................................................................................................56 Hypothesis 2 ........................................................................................................59 Hypothesis 3 ........................................................................................................59 Hypothesis 4 ........................................................................................................59 3 RESULTS...................................................................................................................60 Taxometric Analyses ..................................................................................................65 Suitability ............................................................................................................66 Mean above Minus below a Cut..........................................................................68 Maximum Covariance .........................................................................................70 Maximum Eigenvalue .........................................................................................71 Consistency Test..................................................................................................71 Cluster Analysis..........................................................................................................72 Intellectual Ability and Cognitive Malingering..........................................................73 Operating Characteristics of the Malingering Measures ............................................76 Strategies for Feigning Cognitive Impairment ...........................................................79 Visual Analogue Scale ........................................................................................79 Malingering Strategies.........................................................................................80 4 DISCUSSION.............................................................................................................82 Cognitive Malingering as a Dimensional Construct...................................................84 Intellectual Ability......................................................................................................88 iv Classification Accuracy..............................................................................................91 Limitations to the Present Study and Future Directions.............................................93 APPENDIX A ACCIDENT SCENARIO ...........................................................................................97 B FLOW CHART ..........................................................................................................98 LIST OF REFERENCES...................................................................................................99 BIOGRAPHICAL SKETCH ...........................................................................................113 v LIST OF TABLES Table page 3-1 Continuous demographic variables .........................................................................60 3-2 Categorical demographic variables .........................................................................61 3-3 Performance on clinical measures (raw scores) ......................................................62