Attenuating Belief Bias Effects in Syllogistic Reasoning: The Role of Belief-Content Conflict by Michelle Colleen Elizabeth Hilscher A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Psychology University of Toronto © Copyright by Michelle Colleen Elizabeth Hilscher 2014 ii Attenuating Belief Bias Effects in Syllogistic Reasoning: The Role of Belief-Content Conflict Michelle Colleen Elizabeth Hilscher Doctor of Philosophy Psychology University of Toronto 2014 Abstract A reasoner’s beliefs can compromise or inflate the accuracy of their syllogistic judgments when syllogistic content and structure are incongruent or congruent, respectively. An integrated approach to the study of syllogistic reasoning led to the investigation of premise-based belief- content conflict and its impact on belief bias. The belief-content conflict cue attenuated belief bias in incongruent valid and invalid trials, as well as congruent invalid trials. Its efficacy was found to depend on the difficulty level of the syllogism in which it was embedded and the location of its placement. Reaction time analyses were used to guide interpretations about the relative engagement of Systems 1 and 2. The key findings suggested that belief-content conflict activated System 2 for invalid incongruent trials which would otherwise have been processed using low-cost heuristic means due to their inherent difficulty. In contrast, it appeared that in valid trials the cue led to a redirection of System 2 resources such that specialized analytic strategies were applied in incongruent trials preceded by belief-content conflict compared to those lacking this cue. Finally, belief bias was successfully offset by belief-content conflict even in cases of congruency. In congruent invalid trials without this cue participants’ intuitive awareness of the content-structure match appeared to lead to low-cost, belief-based guesses; yet when presented as the major premise this conflict cue appeared to shift System 1 processing away from content and towards structure. Albeit less diligent than System 2 analysis, the shallow iii consideration of structural features may have been viewed as a safer bet than any shortcut aiming to capitalize on syllogistic content. This set of findings cannot be fully accounted for by the selective scrutiny, misinterpreted necessity, mental models, verbal reasoning, selective processing, or Receiver Operating Characteristics accounts thereby highlighting the need for considering belief-content conflict in future models of belief bias. iv Acknowledgements I would like to express my gratitude to Gerry for his support and encouragement throughout the years we have worked together. Above all else, you have inspired in me an enduring interest in the history and philosophy of science. Thank you Oshin and Morris for your guidance; together you have ensured that I know the little details and also see the big picture. Finally, to Arthur, my family, and my friends – thank you for being wonderful and never losing faith in my ability to complete this process! v Table of Contents Chapter 1: The Syllogistic Reasoning Paradigm 1 The logical syllogism Structural variables Content variables The typical logical syllogism task Why do syllogistic reasoning errors occur? The atmosphere effect Ambiguity and caution The conversion error Probabilistic reasoning The belief bias effect Syllogistic reasoning errors may not reflect flawed reasoning The figural effect Elaborating the role of structural variables Which is dominant? Atmosphere or conversion? What about figure, does it factor in as a source of syllogistic reasoning errors? Summary: Structural variables Chapter 2: Reassessing the Relationship Between Structure and Content 21 The historical polarity of structure and content New Criticism History of psychology An attempted rapprochement of structure and content Elaborating the role of content variables Establishing that belief bias is a genuine phenomenon Conditions that inspire belief bias i. emotional content ii. emotional frame of mind iii. emotional content and emotional reasoners iv. working memory and executive functioning v. other personal qualities of the reasoner vi. argument variables vii. source credibility Why belief bias happens Reaching a consensus by the eighties? Chapter 3: Syllogistic Reasoning Models 53 The selective scrutiny model The misinterpreted necessity model The mental models account Verbal reasoning theory Selective processing account Receiver operating characteristics account Comparing the models vi Chapter 4: Developing an Integrated Approach to Belief Bias 74 Reconciling the models Multiple analytic processes are possible Analytic processing is distinct from heuristic processing The heuristics system Evidence for dual-process systems Heuristic and analytic system interaction i. system 1 predominates ii. systems 1 and 2 are processing partners iii. system 2 can act on system 1 iv. system 1 and 2 process the same information, albeit in discrete ways v. system 2 specialists are a distinct ‘type’ of person Chapter 5: The Current Project 101 Content, context, and beliefs can improve analytical strategies Premise plausibility Purpose of current studies Chapter 6: Belief-Content Conflict Attenuates Belief Bias 115 Study 1A Rationale and expectations Methods Results Does the ‘warning signal’ effect translate into ensuing trials? Summary of findings and preliminary interpretations Chapter 7: Belief-Content Conflict Impacts Semantic Processing 142 Study 1B Rationale and expectations Methods Results Summary of findings and preliminary interpretations Chapter 8: Efficacy of Belief-Content Cue Depends on Syllogistic Difficulty Level 157 Study 2 Rationale and expectations Methods Results Chapter 9: Belief-Content Conflict Can Inspire Conclusion-Content Blocking 179 Study 3 Rationale and expectations Methods Results Evaluating semantic plausibility – Summary of findings and preliminary interpretations vii Chapter 10: Discussion 201 Belief-content conflict attenuates belief bias Valid trials Invalid trials System 1 versus System 2 i. strategy shifting and activation ii. inhibition The six models of reasoning Extension beyond the six models Conclusion References 224 Appendices 238 End Note 250 1 CHAPTER 1: THE SYLLOGISTIC REASONING PARADIGM Reasoning and the evaluation of logical syllogisms have long been celebrated activities. In the 6th Century BC, the Formalists of Asia Minor attempted to deduce the ultimate nature of the universe by reasoning about mathematical rules. Plato instructed his pupils to deduce truths about life from premises that were assumed to be innate and universally accessible. Following in this vein, the German Rationalists of whom Gottfried Leibniz (1646-1716) was one, elaborated on the nature of this innate knowledge, proposing that number, space, time, substance, and causality are inherent contents of the mind. George Berkeley (1685-1753) went so far as to claim that the world is created in an entirely top-down fashion; thus deduction and perception are one and the same (Benjafield, 2010). Historically speaking, logical thinking and syllogistic reasoning were often viewed as morally superior to emotional experience and intuition. It was assumed by numerous scholars that reasoning was the process that would yield the truest product – sound knowledge about life and the universe. Despite this philosophical orientation towards the product of reasoning, experimental research on syllogistic reasoning has mostly been aimed at uncovering how reasoning occurs – an orientation towards the process. For instance, researchers in the 1930s through 1960s debated the conditions under which accurate and inaccurate syllogistic reasoning are likely (e.g., Woodworth & Sells, 1935; Janis & Frick, 1943; Chapman & Chapman, 1959). Janis and Frick (1943) proposed that reasoning may go off track when reasoners are swayed by their beliefs; this was the first time that the belief bias effect was proposed. Janis and Frick’s (1943) work was followed up by two streams of research. The first stream assumed that belief bias was a bonafide phenomenon and attempted to elaborate on the conditions that might make it 2 likely to occur (e.g., Morgan & Morton, 1944; Lefford, 1946). The second stream studied sources of reasoning error other than belief bias and implicitly challenged the existence of this phenomenon (e.g., Simpson & Johnson, 1966; Begg & Denny, 1969). In 1983, Evans, Barston and Pollard weighed in on this debate by publishing an article in which they concluded that the belief bias effect exists and that it is indeed a valid explanation for errors in syllogistic reasoning. More recent syllogistic reasoning research marks a splintering in the field as scholars have proposed competing models of reasoning that offer varying explanations for syllogistic reasoning generally, and belief bias more specifically (e.g., selective scrutiny; misinterpreted necessity; mental models account; verbal reasoning theory; selective processing theory; Receiver Operating Characteristics account). Current disagreements about how beliefs are thought to impact syllogistic reasoning may be attributed to the fact that there is currently a lack of consensus about the latter process (Khemlani & Johnson-Laird, 2012). Given this historical framework I would like to make the scope of my own work clear. I have designed a set of logical syllogisms that have allowed me to replicate the belief bias effect. Besides allowing for a replication of this