Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2018 Belief perseverance: The staying power of confession evidence Curt More Iowa State University Follow this and additional works at: https://lib.edu/etd Part of the Social Psychology Commons Recommended Citation More, Curt, "Belief perseverance: The staying power of confession evidence" (2018). Graduate Theses and Dissertations.edu/etd/16421 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact digirep@iastate.
Belief perseverance: The staying power of confession evidence by Curt Craig More A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Psychology Program of Study Committee: Stephanie Madon, Co-Major Professor Max Guyll, Co-Major Professor Marcus Credé The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this thesis. The Graduate College will ensure this thesis is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2018 Copyright © Curt Craig More, 2018. All rights reserved.
ii DEDICATION This thesis is dedicated to my family. To my wife, Kimberly More, for her love and encouragement. To my parents, Susan More, Bruce More, and Joseph Kitzke, for their support, both emotional and financial. To the grandparents I have lost, Kay Brayshaw, Joe Kitzke, and George More, for their unconditional love.
And to the grandparents I still have, Don Brayshaw, Evona Kitzke, and Pat More, for their unwavering love and belief in me. iii TABLE OF CONTENTS Page LIST OF FIGURES. v LIST OF TABLES. 1 Error and Bias.
3 The Power of Confession Evidence. 7 Research Overview and Hypotheses. 12 Perceptions of Impartiality. 16 Commitment Manipulation Check.
16 Confession Timing Manipulation Check. 17 Model 1: Total Effect of Confession Timing on Phase 2 Guilt Judgments. 18 Model 2: Belief Perseverance Effect. 19 Path a: Confession Effect.
19 iv Path b: Judgment Stability. 20 Path a × b: Belief Perseverance. 20 Path c: Adding Confession Evidence and Procedural Effects. 20 Moderation of Belief Perseverance by Commitment.
22 Model 1: Total Effect of Confession Timing. 22 Model 2: Belief Perseverance Effect. 23 Path a: Confession Effect. 24 Path b: Judgment Stability.
24 Path a × b: Belief Perseverance. 25 Path c: Adding Confession Evidence and Procedural Effects. 25 Path a × b + c: Total Effect of Confession Evidence. 25 Moderation of Belief Perseverance by Commitment.
PHASE 1 CRIME REPORT: CONFESSION EARLY. PHASE 1 CRIME REPORT: CONFESSION LATE. PHASE 2 CRIME REPORT. PERCEPTIONS OF IMPARTIALITY.
INSTITUTIONAL REVIEW BOARD APPROVAL FORM. 58 v LIST OF FIGURES Page Figure 1. Participant Verdicts by Condition and Phase. Model 1: Examination of Total Effects.
Model 2: Mediated Model Examining Indirect Effects. 39 vi LIST OF TABLES Page Table 1. Correlations by Commitment Condition. Model 2 Path Coefficients.
44 vii ACKNOWLEDGMENTS I would like to thank some of the incredible mentors I have encountered leading up to this thesis. Leora Dahl for inspiring me to study forensic psychology rather than English. Linda Hatt and the late Dr. Claire Budgen for the opportunity to be a part of a research team as an undergraduate.
Michael Woodworth for his mentorship of my honours thesis. Jan Cioe for his friendship and guidance on how to be a better student, a better teacher, and a better person. Marcus Credé and Dr. Gary Wells for their advice throughout the crafting of this thesis.
And finally to my co-advisors, Dr. Max Guyll and Dr. Stephanie Madon, for their constant support and encouragement, without which this thesis would not have been possible. viii ABSTRACT This research examined whether a criminal confession causes people to discount subsequently encountered exculpatory evidence.
Participants (N = 238) read a crime report across two phases and judged a suspect's guilt after each phase. In phase 1, the crime report presented circumstantial evidence indicative of the suspect's guilt. In phase 2, exculpatory evidence indicative of the suspect's innocence was added. The crime report manipulated whether participants received confession evidence during phase 1 (confession–early) or phase 2 (confession–late).
In addition, some participants publicly committed to their phase 1 guilt judgments prior to receiving the crime report in phase 2 (high commitment), whereas others did not (low commitment). Results provided some support for the hypothesis that a confession biases the way that people use subsequently encountered exculpatory evidence to judge a suspect’s guilt; under conditions of low commitment, participants more often rendered guilty verdicts in the confession–early conditions than the confession–late conditions. The results are discussed in terms of police investigator and juror decision-making. INTRODUCTION It is well-established that a confession, even a false one, is a highly incriminating form of evidence (Kassin, 2008; Leo & Drizin, 2010).
Confession evidence is more powerful than eyewitness and character testimony (Kassin & Neumann, 1997), and can even attenuate the formidable power of DNA evidence under some conditions (Appleby & Kassin, 2016). Jurors will sometimes convict defendants on the basis of confession evidence alone, and they do not appropriately discount confessions that they believed were obtained under duress or that were ruled inadmissible (Kassin et al., 2010; Kassin & Sukel, 1997; Smalarz, Madon, Yang, Guyll, & Buck, 2016). Not surprisingly, jury conviction rates for false confessors are very high, ranging from 73% – 81% (Drizin & Leo, 2004; Ofshe & Leo, 1997). The power of confession evidence stems, in large part, from the widespread belief that suspects, motivated by self-interest, would not confess to crimes that they did not commit unless subjected to physical abuse or torture (Kassin & Wrightsman, 1981).
However, psychological research findings and proven false confession cases reveal this belief to be a misconception. Innocent suspects do sometimes confess to crimes that they did not commit. In fact, false confessions are a leading cause of wrongful convictions in the United States, contributing to the convictions of nearly 28% of defendants who were later exonerated by DNA evidence (“DNA Exonerations Nationwide,” 2016). Although the widespread belief that false confessions only arise under egregious circumstances is not true, it hints at the way that error and bias may contribute to the power of confession evidence.
That is, once people learn that a suspect has confessed, they may develop such a strong belief in the suspect's guilt that they fail to appropriately adjust their guilt judgments in response to subsequently encountered evidence that points to the suspect's 2 innocence. In psychological terms, a confession may elicit belief perseverance – a cognitive bias in which people cling to their original beliefs even when the basis for the belief has been discredited (Nestler, 2010). The idea that belief perseverance may contribute to the power of confession evidence has been hypothesized by legal scholars (Findley & Scott, 2006), but has not been empirically demonstrated. Error and Bias Social psychology has long emphasized the role that error and bias play in perception.
This emphasis dates back at least as far as the 1940s and 1950s when New Look in Perception researchers proposed that people's motivations, needs, goals, and expectations colored their perceptions of reality (Bruner, 1992; Erdelyi, 1974). Bruner and Goodman (1947) provide a classic illustration of this theoretical perspective. They presented 10-year-old children with coins of varying values. In general, the children tended to overestimate the size of the coins, and this tendency increased as the value of the coins increased.
For example, children overestimated the size of a penny by approximately 15%, whereas they overestimated the size of a quarter by more than 35%. These results showed that the children’s perceptions of the coins were influenced by their internal psychological states. As a result of findings such as these, social and behavioral scientists turned their attention to the way that biases may distort judgment and decision-making. Kahneman and Tversky (1973), for instance, introduced numerous cognitive biases and heuristics, and in doing so called into question the prevailing view that people rely on formal statistical rules to make social inferences.
For example, they argued that rather than using base rates to make judgments, people instead have a tendency to make judgments on the basis of similarity, that people infer the frequency of events according to the ease with which examples come to mind, and that people 3 are not sufficiently sensitive to the impact of sample size on probability judgments. The idea that people rely on heuristics when making judgments sparked considerable interest in cognitive biases and the way in which these biases may distort perception. Belief Perseverance Of particular importance to the current research is the cognitive bias of belief perseverance. As previously noted, belief perseverance is the tendency for people to cling to their initial beliefs even after the foundation supporting those beliefs has been discredited (Nestler, 2010).
Numerous studies in the basic psychological literature have demonstrated this effect, with most relying on what is commonly referred to as the debriefing paradigm. The debriefing paradigm involves two groups of participants who receive conflicting information about a topic. Participants in both groups subsequently learn that the information they received is false, after which they make judgments relevant to the discredited information. Although logically, participants should not use the discredited information to make their judgments, the literature consistently shows that they do.
For example, following a discrimination task, participants who received positive feedback rated themselves as having greater discrimination abilities than participants who received negative feedback despite that all participants had earlier been informed that the feedback was false (Ross, Lepper, & Hubbard, 1975). Similarly, participants who were initially informed of a positive relationship between risk- taking and being a successful firefighter continued to rate risky behavior as diagnostic of firefighting success despite having already been debriefed to the false nature of the relationship (Anderson, Lepper, & Ross, 1980). A key strength of the debriefing paradigm is that it permits a decisive test of the belief perseverance effect. That is, because the information on which participants based their initial 4 beliefs was completely discredited, any subsequent between-group difference in judgments that is in the direction of the discredited information shows that participants inappropriately used the discredited information.
However, it is important not to equate the paradigm with the effect. Even though the debriefing paradigm involves the complete discrediting of information, the concept of belief perseverance does not. Failure to revise a belief when the information on which it was based has been partially discredited is also irrational and also constitutes belief perseverance. In addition, restricting the concept of belief perseverance only to situations involving the complete discrediting of information raises conceptual problems.
Most notably, it would mean that beliefs that persevered in the context of less than completely discredited information could not, by definition, indicate belief perseverance. This would be the case even if the degree of discrediting was as high as 99%, and even though the underlying psychological process responsible for the effect is indistinguishable from the process that operates when the degree of discrediting is complete. In fact, psychological theory never conceptualized belief perseverance as restricted to situations involving the complete discrediting of information. For example, in the opening paragraphs of Ross et al.’s (1975) seminal article on the belief perseverance effect, the authors provided examples that specifically involved the partial discrediting of information: a teacher attributes a student’s disengagement to lack of motivation, but later learns that the student is undernourished and sleep deprived; a woman infers romantic interest from a man who gives her flowers, but later learns that the man’s father is a florist.