David V. Canter

Offender profiling and criminal differentiation

Purpose. The psychological hypotheses that form the foundations for ‘Offender Profiling’ are identified and the research that has tested them is reviewed. Argument. ‘Offender profiling’ is taken to be the derivation of inferences about a criminal from aspects of the crime(s) s/he has committed. For this process to move beyond deduction based on personal opinion and anecdote to an empirically based science a number of aspects of criminal activity need to be distinguished and examined. The notion of a hierarchy of criminal differentiation is introduced to highlight the need to search for consistencies and variations at many levels of that hierarchy. However, current research indicates that the key distinctions are those that differentiate, within classes of crime, between offences and between offenders,. This also leads to the hypothesis of a circular ordering of criminal actions, analogous to the colour circle, a ‘radex’. The radex model, tested using Multi-Dimensional Scaling (MDS) procedures, allows specific hypotheses to be developed about important constituents of criminal differentiation: Salience; MDS analyses reveal the importance of the frequency of criminal actions as the basis on which the significance of those actions can be established. Models of Differentiation; the research reviewed mainly supports distinctions between criminals in terms of the forms of their transactions with their explicit or implicit victims, Consistency; offenders have been shown to exhibit similar patterns of action on different occasions. The most reliable examples of this currently are in studies of the spatial behaviour of criminals. Inference; under limited conditions it is possible to show associations between the characteristics of offenders and the thematic focus of their crimes.

Linking commercial burglaries by modus operandi: tests using regression and ROC analysis

This paper uses statistical models to test directly the police practice of utilising modus operandi to link crimes to a common offender. Data from 86 solved commercial burglaries committed by 43 offenders are analysed using logistic regression analysis to identify behavioural features that reliably distinguish between linked and unlinked crime pairs. Receiver operating characteristic analysis is then used to assign each behavioural feature an overall level of predictive accuracy. The results indicate that certain features, in particular the distances between burglary locations, lead to high levels of predictive accuracy. This study therefore reveals some of the important consistencies in commercial burglary behaviour. These have theoretical value in helping to explain criminal activity. They also have practical value by providing the basis for a diagnostic tool that could be used in comparative case analysis.

The organized/disorganized typology of serial murder: myth or model?

Despite weaknesses in the organized/disorganizedclassification of serial killers, it is drawn on for “offender profiles,” theories of offending, and in murder trials. This dichotomy was therefore tested by the multidimensional scaling of the co-occurrence of 39 aspects of serial killings derived 100 murders committed by 100 U.S. serial killers. Results revealed no distinct subsets of offense characteristics reflecting the dichotomy. They showed a subset of organized features typical of most serial killings. Disorganized features are much rarer and do not form a distinct type. These results have implications for testing typologies supporting expert opinion or to help understand variations in criminal acts, as well as the development of a science of investigative psychology that goes beyond offender profiling. The organized/disorganized dichotomy is one of the most widely cited classifications of violent, serial offenders. Although first introduced by the special agents of the U.S. Federal Bureau of Investigation (FBI) Training Academy at Quantico in an examination of lust and sexual sadistic murders (Ressler, Burgess, Douglas, Hartman, & D’Agostino, 1986) the distinction has since been put forward to differentiate all sexual homicides and also types of arson in Douglas, Burgess, Burgess, and Ressler’s (1992) Crime Classification Manual. These authors have made the distinction between organized and disorganized offenders on criteria that they claim can be drawn from an examination of the crime scene, the victim, and forensic reports. Ressler et al. (1986) claimed that “. . . facets of the criminal’s personality are evident in his offense. Like a fingerprint, the crime scene can be used to aid in identifying the murderer” (p. 291). They proposed that offenders’ behavioral and personality characteristics can be determined from evidence at a crime scene (Ressler et al., 1986). This “fingerprint” is proposed to take one of two distinct forms, either organized or disorganized. The organized offender is described as leading an orderly life that is also reflected in the way he commits his crimes. Highlighting some proposed characteristics, he is claimed to be of average to high intelligence, socially competent, and more likely than the disorganized offender to have skilled employment. It is also claimed that he is apt to plan his offenses, use restraints on his victim, and to bring a weapon with him to commit the murder and to take the weapon away with him from the crime scene. In contrast, the crime scene of the disorganized

The Purposive Evaluation of Places A Facet Approach

A multivariate, purposive model of the experience of places is offered as a theoretical basis for place evaluation. This model suggests a structure to the evaluation of places that may be generalizable across most settings. The structure derives from the definition of place evaluation as the degree to which a person sees a place as helping to achieve that persons goals at various levels of interaction with that place. In order to test empirically this framework, use is made of the facet approach to theory specification and hypothesis testing. Smallest Space analyses of two large scale questionnaire surveys, one of housing satisfaction and the other of hospital ward design, provide strong support for the purposive model. Implications of this multivariate model for future evaluations are discussed, together with the value of harnessing the facet approach to aid the development of evaluation theory.

Distance Estimation in Cities.

A property of the physical environment of distinct psychological importance is the fact that the environment completely surrounds us. Thus it is not possible for us to experience or perceive all of it at any one instant. We can only turn our attention to discrete aspects of the environment at successive points in time. However, in order for our behaviour to be appropriate, effective, or adequate in relation to the physical environment, it is necessary for it to proceed in a continuous fashion. To explain the way in which this discrete experience

Predicting Serial Killers' Home Base Using a Decision Support System

The effectiveness of a geographical decision support tool (Dragnet) forlocating the base of serial offenders was compared across 570 modelscomprised of a range of negative exponential functions, buffer zonecomponents, and normalization parameters. The models were applied to thebody disposal locations within each series for 70 U.S. serial killers. Twonormalization parameters were compared for all functions. The test ofeffectiveness was a specifically defined measure of search cost. Whenapplied to the Dragnet predictions it was found that the specially developednormalization parameter (QRange) produced the optimal search costs. Theoptimal search cost was also found to be for a function that did not includeany buffer zone. The optimal, average search cost across the whole samplewas 11% of the defined search area. Fifty-one percent of the offendersresided in the first 5% of the search area, with 87% in the first 25%. Allresided in the total defined search area. These results support thepotential for operational tools using such procedures as well ascontributing to our understanding of criminals geographicalbehavior. The applicability to other forms of serial crime is considered.

The Facets of Place

This chapter will outline one theory aimed at integrating aspects of environmental psychology with issues in architectural design. The theory to be reviewed is broad in those characteristics of theory that Moore (1987) called their “form and scope.” This broadbrush, top-down approach is intended as a contrast with bottom-up attempts to specify the behavioral effects of specific aspects of design, such as lighting levels or size of spaces. It also contrasts with models that seek to answer immediate design problems. However, in Moore’s (1987) vocabulary, the theory to be outlined is more than an “orientation,” or “framework.” It is an “explanatory theory” that has been found to have considerable scope and to be open to direct empirical test.

An Empirical Test of Holmes and Holmes’s Serial Murder Typology:

This article presents the results of an empirical test of Holmes and Holmes’s serial murder classification scheme. Crime scene evidence from 100 U.S. serial murders, each the third in a distinct series, was content analyzed. The co-occurrence of content categories derived from the crime scene material was submitted to smallest space analysis. The features characteristic of the category of “power or control” killings were found to be typical of the sample as a whole, occurring in more than 50% of cases, and thus did not form a distinct type. Limited support was found for aspects of the lust, thrill, and mission styles of killing, but this support drew attention to differences in the ways victims were dealt with, through mutilation, restraints, or ransacking their property rather than the motivations implicitly inferred in Holmes and Holmes’s typology. The current results are presented as an empirical basis for the classification of serial killings on which more detailed models can be built.

Victims and Perpetrators of Male Sexual Assault

Within the literature, two differing accounts of male sexual assault are hypothesized—one is the view that it is perpetrated by offenders who are characteristically homosexual, and the other that it is an example of heterosexual violence. Two studies were conducted that explored these opposing possibilities. The first was an analysis of data collected from two sources—83 victim self-report questionnaires and review of 36 investigated police reports. The results indicated that homosexual offenders were more likely to have known their victims for some time and target those under the age of 25. Heterosexual offenders tended to attack strangers of all ages and were more likely to operate in gangs. A comparison of the two samples indicated that the acquaintance sexual assault was less likely to be reported to the police, drawing attention to the fact that differing explanations may be strongly influenced by the particular sample under study.

The decision to evacuate: a study of the motivations which contribute to evacuation in the event of fire☆

Abstract This paper reviews the literature relevant to the issue of motivation to evacuate a building in the event of fire. Two traditional approaches to evacuation research, the physical science and ‘panic’ approaches are considered critically. It is argued that they lead to a mechanistic explanation of motivation. The findings of three recent psychological studies are then presented. These introduce a model of human action which illustrates that evacuation is not motivated by discrete factors but is derived from information processing and decision making. The implications of this new analysis for future research are discussed.