Explaining that feeling of familiarity

THE DEJA VU EXPERIENCE. A. S. Brown. Psychology Press, New York, 2004. No. of pages 201.ISBN 1-84169-075-9. Price £27.99 (hardback).

The phenomenon of deja vu—a subjective feeling of familiarity, of having been in a place, engagedin a particular activity, heard or said a particular phrase once before despite knowing objectively thatthis cannot be the case—is an everyday experience that is familiar to many. The phenomenon hasreceived much attention from writers in a wide variety of disciplines including philosophy, religion,literature, neurology, sociology and psychology. In the current volume, the author attempts to gathertogether information from these diverse sources to provide a detailed review of how the phenomenonhas been defined and described, and considers how more recent theorizing in the fields of perception,cognition and neurophysiology may help to understand the cause of the deja vu experience.

The first nine chapters of the book are devoted to historical approaches to the study of deja vu,covering attempts to define the phenomenon and characterize the incidence and nature of deja vuexperiences. Such experiences have typically been studied using retrospective surveys, plus a fewprospective surveys, and the author reviews a large body of work dating from the 1800s to the presentday. Brown points out that many of the individual surveys of deja vu experiences are flawed, beingcharacterized by unrepresentative samples, a tendency to embed questions about deja vu experiencesamong items evaluating paranormal experiences or presenting them in a manner implying anassociation between deja vu and various forms of psychopathology. Despite these flaws however, theauthor has been able to identify a number of consistent findings about deja vu experiences acrossthese studies. It has been found that the general incidence of such experiences tends to be higher inmore recent surveys, and in surveys with younger respondents. Deja vu experiences are typicallytriggered by the general physical setting, or by words and phrases spoken by the individual or otherpeople. These experiences can occur in settings that are new, or in familiar or routine locations, butregardless of location most experiences occur while the individual is engaged in ordinary, mundaneactivities. A notable finding across studies is the negative association between deja vu and age—it isexperienced by a higher proportion of younger than older people, and in the case of individuals whoexperience deja vu, the frequency of such experiences declines with age. This may be explained byan increase in the cultural acceptability of the illusion in recent decades, but no other satisfactoryexplanation has been proposed. Deja vu experiences are positively related to levels of education, andmore common in individuals who travel widely, have higher incomes and remember their dreams. Itis less common in individuals of conservative political views and among those with strong religiousbeliefs. There is some evidence that deja vu experiences are characteristic of individuals withtemporal lobe epilepsy and there appears to be a higher incidence of deja vu experiences amongindividuals who consume alcoholic drinks compared to non drinkers. The author presents a hugevolume of information in these chapters, and at times this might leave the reader feeling ratheroverwhelmed. However each chapter ends with a useful summary of the material covered whichhelps to alleviate this.

From chapter ten onwards the author begins to consider in detail how psychology can explain thisphenomenon. He starts with two brief chapters examining explanations from parapsychology (e.g.telepathy, reincarnation) and psychodynamics (e.g. repressed memories, wish fulfilment). The authordoes not regard such explanations as useful for gaining an understanding of deja vu and presentsthem simply for the purposes of providing a complete historical account of the nature of research andtheorising on the phenomenon. He then moves on to consider more plausible and potentially testablescientific explanations of deja vu from mainstream psychology. This is done in a series of individualchapters covering dual process, neurological, memory and double perception explanations of dejavu. Dual processing explanations assume that two cognitive processes that normally operate in acoordinated manner momentarily fall out of step with each other, for example when familiarityoccurs in the absence of retrieval. Neurological explanations view deja vu as a brief interruption tonormal brain activity. This may involve a small seizure or a slight acceleration/retardation in thenormal time course of neural transmission. Memory explanations see deja vu as occurring insituations in which some aspect of the current setting is objectively familiar, but the source of thisfamiliarity is not explicitly recollected. Double perception accounts view deja vu as occurring insituations where an initial perception under distraction or degraded conditions is followed

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Copyright # 2005 John Wiley & Sons, Ltd. Appl. Cognit. Psychol. 19: 375–381 (2005)

immediately by a second perception under conditions of full attention. Within each of these broadclasses of explanation of deja vu there are various individual accounts which are reviewed in detailby the author. He does not come out in favour of any one explanation for the phenomenon, as the aimof the book is to consider the many possible explanations of deja vu that contemporary psychologicalresearch has to offer and act as a stimulus for future research on this topic. The book ends with asummary of the existing findings on deja vu reviewed in the earlier chapters, and he identifies somefuture issues for research on the topic including suggestions for improved survey research on deja vu,and possible laboratory-based studies based on the dual process, memory and double perceptionapproaches to deja vu.

Overall this book is an interesting and enjoyable read. The author has done a fine job ofassembling and summarizing such a large and diverse body of work covering a long period of time.He demonstrates that the phenomenon is by no means beyond the reach of mainstream cognitivepsychology and this book will be an invaluable source for those interested in researching thisintriguing phenomenon.

KEVIN CROWLEYUniversity of Glamorgan, UK

Published online in Wiley InterScience(www.interscience.wiley.com) DOI: 10.1002/acp.1118

An accessible text for forensic psychology undergraduates

INTRODUCTION TO FORENSIC PSYCHOLOGY. C. R. Bartol and A. M. Bartol. Sage Publica-tions, California, 2004. No. of pages 500. ISBN 0-7619-2606-2. Price £28.99 (hardback).

Bartol and Bartol’s Introduction to Forensic Psychology undertakes an ambitious task, seeking toprovide both a historical and a contemporary perspective of forensic psychology, to introduce thereader to relevant psychological research and theories, to describe the application of this knowledgeto specific issues within those systems and to inform the interested reader of the various training andcareer paths open within these fields (albeit with a strong US bias). The latter may be of particularuse to the student readership (both under- and post-graduate) at which the book is primarily aimed,and is something that seems to be considered only rarely in psychology textbooks—althoughwhether this is sufficient to qualify as a unique selling point will depend on the individual reader.

Whilst the authors recognize that the focus of many forensic psychology courses within the UStends towards ‘clinical’ forensic psychology (a focus also reflected within some courses in the UK),their intent within this book is to offer a far broader approach considering psychology’s applicationto all aspects of ‘the criminal and civil justice systems’. To this end the book opens with a concise,but quite comprehensive, introductory chapter outlining the many areas of application of psychologywithin the forensic context from offenders and offending, through the investigative and judicialprocesses (including victim support issues), to assessment, treatment and rehabilitation of offenders.The book is then subdivided into five further chapters, considering specific domains of psychologicalapplication, each of which is briefly described separately below.

The chapter entitled ‘police and investigative psychology’ covers the application of psychology toboth police officers themselves and the work they do. The former has much in common withoccupational psychology (not something which I had previously associated with forensic psychol-ogy, so it offered me an interesting new perspective), whilst the latter considers investigativeelements such as offender profiling, deception detection and suspect identification as well as morecontroversial techniques such as ‘forensic hypnosis’ and the use of ‘psychological autopsies’. It isthis chapter which is perhaps of most relevance for applied cognitive psychologists, although thecoverage of memory, cognition and perception in terms of witness (verbal and visual) evidence is notespecially extensive. The chapter ‘criminal psychology’ describes various types of offender andoffending, including various demographic, personality and behavioural factors associated withoffenders both ‘normal’ and disordered (although with much more weight given to the latter). The

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Copyright # 2005 John Wiley & Sons, Ltd. Appl. Cognit. Psychol. 19: 375–381 (2005)