EYEWITNESS IDENTIFICATION AND THE WEAPON FOCUS EFFECT: EFFECTS OF WEAPON PRESENCE, CONCEALMENT, AND EXPOSURE TIME A Dissertation by JENNIFER L. DIAS Submitted to the Office of Graduate Studies of Texas A&M University-Commerce in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2017 EYEWITNESS IDENTIFICATION AND THE WEAPON FOCUS EFFECT: EFFECTS OF WEAPON PRESENCE, CONCEALMENT, AND EXPOSURE TIME A Dissertation by JENNIFER L. DIAS Approved by: Advisor: Curt Carlson Committee: Maria Carlson Lacy Krueger David Hurley Head of Department: Jennifer Schroeder Dean of the College: Timothy Letzring Dean of Graduate Studies: Mary Beth Sampson iii Copyright © 2017 Jennifer L. Dias iv ABSTRACT EYEWITNESS IDENTIFICATION AND THE WEAPON FOCUS EFFECT: EFFECTS OF WEAPON PRESENCE, CONCEALMENT, AND EXPOSURE TIME Jennifer L. Dias, PhD Texas A&M University-Commerce, 2017 Advisor: Curt Carlson, PhD The study examined the effect of exposure to the perpetrator and weapon visibility on the weapon focus effect (WFE). Participants were presented a mock crime video with the perpetrator holding either no weapon, a visible weapon, or a concealed weapon which he refers to and creates a bulge in his clothing. One exposure condition exposed the witness to the perpetrator and weapon for approximately 25 s and another for approximately 35 s from a distance of 2-4 m. After watching the video, participants were asked to make an identification decision from either a perpetrator-present or -absent lineup and rate their confidence in that decision. The first prediction was that the WFE would be replicated in the bad, but not good view of the perpetrator. A second prediction was there would be no WFE in the concealed condition for either good or bad view of the perpetrator. A final prediction was that those presented with the good view of the perpetrator would out-perform those presented with the bad view, regardless of weapon presence. Participants with a bad view of the perpetrator were more likely to falsely identify a foil from a perpetrator-absent lineup. Unexpectedly, the visible weapon condition produced v fewer correct identifications than concealed and no weapon conditions. Accuracy was highest in the concealed and visible weapon conditions. vi ACKNOWLEDGEMENTS This dissertation would not have been possible without the support of my family, friends, and colleagues. The journey to completion has been long, but the endless amounts of encouragement and motivation from all have kept me going. Especially these past two years while I have battled breast cancer. This is for Quade, my reason and inspiration for everything since the day he was born. Thank you for always knowing just what to say when I needed it most. A special thank you to Bryan. He entered this journey when the hardest part began. Thank you for taking care of me and always having faith that I could endure it all. Thank you to those participating on my committee. Your contributions are appreciated and valued. An extra special thank you to Dr. Curt Carlson. He will never know the breadth of what he has taught me. He gave me not only a field of study to love but also has taught me more about writing and statistics than anyone else in my academic journey. As a result, confidence in my ability to successfully contribute to research in eyewitness identification grows daily. I hope to collaborate with him on future projects. I will be forever grateful for his leadership and the time he graciously donated to help me achieve this goal. vii TABLE OF CONTENTS LIST OF TABLES ..................................................................................................................... viii CHAPTER 1. INTRODUCTION ...................................................................................................... 1 Statement of the Problem ..................................................................................... 3 Literature Review ................................................................................................. 4 The Weapon Focus Effect ........................................................................ 5 The arousal hypothesis of the weapon focus effect ..................... 6 The unusualness hypothesis of the weapon focus effect ............. 9 Law enforcement and the weapon focus effect .......................... 15 Weapon concealment ................................................................. 18 Exposure time to the perpetrator ............................................................ 20 Hypotheses ......................................................................................................... 23 2. METHOD ................................................................................................................. 25 Participants ......................................................................................................... 25 Materials ............................................................................................................ 25 Procedure ........................................................................................................... 26 Design and Analysis .......................................................................................... 27 3. RESULTS .................................................................................................................. 28 Identifications from perpetrator-absent vs. perpetrator-present lineups ............ 28 Signal detection analysis .................................................................................... 29 Eyewitness recall ............................................................................................... 30 4. DISCUSSION ........................................................................................................... 32 viii Limitations ......................................................................................................... 33 Future Directions ............................................................................................... 35 Conclusions ........................................................................................................ 37 REFERENCES ............................................................................................................................ 38 APPENDICES ............................................................................................................................ 45 A. Links to mock crime videos ............................................................................... 46 B. Example of perpetrator present lineup (perpetrator in position 4) ..................... 48 C. Example of perpetrator absent lineup ................................................................. 50 D. Memory Questionnaire ....................................................................................... 52 E. Demographics ...................................................................................................... 54 VITA .......................................................................................................................................... 56 ix LIST OF TABLES TABLE 1. Identification and Rejection Rates across Conditions ................................................... 37 2. Recall Accuracy across Conditions ............................................................................... 39 1 Chapter 1 INTRODUCTION Guilt or innocence is often determined by the ability of an eyewitness to pick a suspect out of a lineup. However, failing to identify the guilty or misidentifying the innocent are potential errors made by an eyewitness (Clark, Benjamin, Wixted, Mickes, & Gronlund, 2015). Despite the knowledge that memory is vulnerable to error and does not capture a perfect account of the event, the criminal justice system relies heavily on eyewitness identification. The Innocence Project (2016) reports that eyewitness identification is the primary cause of wrongful convictions in cases involving DNA evidence. Out of the first 325 wrongful convictions overturned by DNA, 235 (72%) were due in part to eyewitness misidentification. The reliability of eyewitness identification was questioned as early as 1907 by Hugo Munsterberg. His book On the Witness Stand, containing essays on psychology and crime, including the fallibility of eyewitness memory, was an early influence in the fields of psychology and law (Memon, Mastroberadino, & Fraser, 2008). Borchard (1932), a law professor at Yale, wrote a book outlining 65 wrongful convictions and found eyewitness identification to be a key contributor. Wells (1978) introduced a categorization system for two categories of variables affecting eyewitness identification: system and estimator variables. The criminal justice system controls system variables and researchers frequently study them in hopes of reducing eyewitness inaccuracy. Examples include the type of lineup presented, instructions given to the witness, and the amount of time between the crime and communication with witnesses. The justice system does not control estimator variables, but they still affect identification accuracy. Examples 2 include conditions at the time of encoding, characteristics of witness and perpetrator, race, and weapon presence during a crime. Researchers have focused mainly on system variables, particularly lineup types (Steblay, Dysart, & Wells, 2011). Although estimator variables have not received as much attention from researchers, weapon presence during a crime