Title: Dual processes in reasoning: A neuropsychological study of the role of working memory.
Funder: Economic and Social Research Council

Abstract: How do we make decisions in a complex and ever-changing world? Contrary to what many people think, we seldom work through a problem by weighing up evidence in a clear and logical manner to arrive at the best decision. Instead, it seems that we use many feelings to guide our decision making. For instance, in his best-selling book, 'Blink', Malcom Gladwell shows that we often make decisions based on very 'quick and dirty' assessments of evidence, relying on stereotypes and beliefs rather than logical reasoning. We can, however, think in a logical manner when the conditions are right, although some people do this more readily than others. In fact, many decisions we make seem to involve an interaction between beliefs and logical reasoning. Sometimes these processes can conflict with one another, imagine Captain Kirk and Doctor Spock struggling over some thorny judgment, and in order to make a decision one must win out. This research project investigates how psychological conflicts like these are resolved by the brain. It does this by applying many neuroscientific techniques to the study of the phenomenon of belief bias in reasoning. Belief bias describes the observation that people are more likely to agree that an argument is logically correct if the conclusion is in line with what they believe to be true. People differ in the degree to which their decisions reached through reasoning are based on logic or belief. Some people are better able than others to suppress erroneous belief bias when logical thinking is called for. Why is this? What differs in the brains of people who show belief bias to a greater or lesser degree? We aim to find out by testing groups of people who show a range of cognitive abilities and by manipulating logical thinking using instructions. By doing this we will understand better the neurological and cognitive bases for a leading theoretical account of human reasoning abilities which proposes that decision making involves two fundamentally different kinds of thinking, or 'dual processes'. Dual-process theory posits that there are two types of mental processes involved in reasoning. It has recently been argued that the essential difference between these two types is their reliance on working memory, which is the ability to hold and manipulate information 'on-line'. Type 2 (reflective) processing requires and taxes working memory while Type 1 (intuitive) processing does not. To date there has been only limited direct investigation of how working memory resources shape human reasoning and no research relating individual differences in working-memory capacity, Type-1 and Type-2 processes in reasoning, and brain function together. This programme of research will address this gap in our knowledge. Understanding the mental and neurological processes involved in decision making is a worthy goal in itself, but there are wider benefits that may follow from this research programme. Decision making in the real world can sometimes have serious consequences and a better understanding of how people reason using logic and beliefs may suggest strategies to maximise success and avoid common errors. Identifying the mechanisms whereby belief bias works may yield strategies to combat it in domains in which a logical weighing of evidence is critical. For instance, the results of the current research programme may inform as to whether it would be more efficacious to focus training efforts on the understanding and application of logical rules, or on strategies to maximise mental control and the inhibition of sources of bias.


Research activity codes: 1.2 PSYCHOLOGICAL AND SOCIOECONOMIC PROCESSES
Health categories: MENTAL HEALTH