Abstract
People with psychological disorders often hold, or appear to hold, aberrant, and frequently blatantly false beliefs. Furthermore, there are clear links between what they do and the beliefs they hold. These links may be generated by processes of reasoning, and may connect the aberrant beliefs with less controversial ones. In addition, false beliefs are always vulnerable to a reality check, and any revision they require may also depend on reasoning processes. Are people with psychological disorders bad at reasoning, perhaps in the sense that they are more prone than others to fallacious inferences? Or do they fail, more than others, to engage in the kind of reasoning that might show that their beliefs are incorrect? These issues can be, and have been, crucial in deciding how to respond to people seeking help for causes of mental distress in their lives. Indeed, Aaron Beck (1976) and his many followers—not mentioned as frequently as one might have expected in this book—have, with some success, instigated a method of treating neurotic symptoms using techniques that attempt to correct false beliefs and faulty reasoning.
Delusional beliefs, which many of the authors in the current volume investigate, are more commonly associated with schizophrenia than with core targets of cognitive behavioural therapy, although Balzan et al. argue persuasively for further evaluation of a promising and clearly specified metacognitive approach to delusion in the closing chapter. The primary focus of this book is, however, more specific than the title might suggest, namely whether delusional beliefs result from a tendency to jump to conclusions (JTC) on the basis of insufficient evidence. This account of aberrant beliefs contrasts with one based primarily on the notion of abnormal perception, championed by Maher (1974) and incorporated into more recent two-factor accounts. The primary tool in JTC research is the beads task, developed in the 1960s by Ward Edwards (Phillips & Edwards, 1966) to study decision-making more generally. There are many variants of this task, but the critical question is whether a sequence of beads of two colours (say black and white) comes from a jar with proportions N black and M white or one where it is M black and N white (common values of N and M are 85 and 15 or 60 and 40). A problem in such research is that while jumping to a conclusion from seeing a very small number of beads—sometimes only one—can readily be demonstrated in some schizophrenics, these individuals usually differ from comparison groups in other ways that may be relevant to how they reason. Indeed, several of the current authors suggest that these other differences, rather than differences in reasoning per se, underlie performance in the beads task. A more critical issue for this approach is explaining the genesis and, to a lesser extent, the maintenance of delusional beliefs. In the beads task there are two externally specified hypotheses that the evidence is supposed to bear on (60 white and 40 black vs 40 white and 60 black, for example). But where does the content of the delusional beliefs of schizophrenics come from?
This book provides an interesting introduction to an important area of research, with well-argued, nicely critical overviews that are essential reading for those entering the field. In addition to the work on schizophrenics, there are chapters on paranormal beliefs and phobias. The authors’ attempts to link their work to the broader literature on thinking and reasoning—two-process theories in particular—are welcome. JTC, bias against disconfirmatory evidence (BADE) and other biases invoked to explain aberrant beliefs clearly derive from what has come to be called System 1 thinking, the fast, automatic, intuitive thinking that proceeds with little voluntary control. There are, however, places where the links could be drawn out more fully. Another crucial theoretical issue, where the consideration of aberrant beliefs might be particularly helpful, is in understanding the relation between cognition and affect. For example, there is a sense in which spider phobics know that house spiders in the UK are not dangerous, but their affect to spiders drives their behaviour. Johnson-Laird, Mancini, and Gangemi's (2006) hyper-emotion theory of psychological illnesses, an alternative attempt to integrate reasoning, affective reaction, and mental distress, might usefully have been considered in this context. Finally, taking a broader view of mental health problems, the ideas and analyses presented in this book should be applicable to other conditions associated with beliefs that are aberrant. Indeed, many, if not all, mental health problems involve beliefs that are seriously at odds with reality. All in all, therefore, there are many fronts on which the research presented in this volume can usefully be taken forward.