Finding a serial burglar's home using distance decay and conditional origin–destination patterns: a test of empirical Bayes journey-to-crime estimation in the Hague

Can we tell where an offender lives from where he or she commits crimes? Journey-to-crime estimation is a tool that uses crime locations to tell us where to search for a serial offender's home. In this paper, we test a new method: empirical Bayes journey-to-crime estimation. It differs from previous methods because it utilises an ‘origin–destination’ rule in addition to the ‘distance decay’ rule that prior methods have used. In the new method, the profiler not only asks ‘what distances did previous offenders travel between their home and the crime scenes?’ but also ‘where did previous offenders live who offended at the locations included in the crime series I investigate right now?’. The new method could not only improve predictive accuracy, it could also reduce the traditional distinction between marauding and commuting offenders. Utilising the CrimeStat software, we apply the new method to 62 serial burglars in The Hague, The Netherlands, and show that the new method has higher predictive accuracy than methods that only exploit a distance decay rule. The new method not only improves the accuracy of predicting the homes of commuters—offenders who live outside their offending area—it also improves the search for marauders—offenders who live inside their offending area. After presenting an example of the application of the technique for prediction of a specific burglar, we discuss the limitations of the method and offer some suggestions for its future development. Copyright © 2009 John Wiley & Sons, Ltd.     

Triangulation mobility of auto‐theft offenders

This research paper presents an examination of the journey to and from crime for auto‐theft offenders in the UK. For 852 offences, ‘wheel’ distances are calculated for triangles formed by offenders' home location, theft location, and vehicle disposal location. The study demonstrates typical isosceles mobility triangles; distances travelled to and from home locations are roughly equal, whereas distances between theft and disposal points were shorter. Distances travelled by offenders under 17 years old and offences involving drug and drink were shown to be shorter than comparison groups. Prolific offenders tend to travel further, although there is significant variation in this subgroup. Explanations and implications are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Crime location choices: A geographical analysis of German serial killers

The present study examined whether there are different processes operating in the crime location choices between body‐disposing and non‐body‐disposing serial killers and between sexual serial killers and acquisitive serial killers. A sample of 49 series of solved German serial killings is used to examine the differences in travelled distances between these groups of killers. Nonparametric tests revealed that body‐disposing and non‐body‐disposing serial killers and sexual and acquisitive serial killers did not constitute subgroups of serial killers regarding their spatial behaviour. The results suggest that the compared groups are subjected to the same factors that influence their travelled distances. Furthermore, the possible role of planning and anticipated emotions in crime location choices of serial killers is discussed, as well as the limitations of the study and recommendations for future research.     

Spatial patterns of Indian serial burglars with relevance to geographical profiling

Earlier studies in Western countries have shown remarkably consistent spatial patterns in serial offenders, mainly for serious crimes notably serial killing and rape, but also (although with less clear patterns) for burglary. The universality of such spatial patterns are of theoretical interest in contributing to our understanding of criminal spatial behaviour and have practical significance for the possibility of using geographic profiling in developing countries. As such, burglars in India provide a particularly interesting test of the generality of the observed spatial consistencies. Information was therefore obtained on the offence location choices of 30 burglars, committing 150 offences in the Rourkela and Keonjhar districts of India. The home to crime distances were compared with those from developed countries, revealing similar but slightly shorter distances. In addition, the domocentricity of criminal spatial activity, reflected in the ‘marauder’ model (Canter & Gregory 1994) was tested through examination of the Canter Circle hypothesis, the mean interpoint distances (as they related to average distances from home), and the home base ‘search costs’ using a geographical profiling system (Dragnet). Overall the study found that the spatial patterns of the sample of Indian Burglars were not very different from their counterparts in the UK, North America and Australia, showing that the areas in which an offender is active tend to be shaped by, and, relatedly, close to, where he or she lives, irrespective of the part of the world in which this is. These results suggest that geographical profiling systems such as Dragnet would be productively used on the Indian sub‐continent. The results also contribute to our understanding of possible universalities in offender spatial behaviour. Copyright © 2006 John Wiley & Sons, Ltd.     

Exploring Directional Consistency in Offending: The Case of Residential Burglary in The Hague

Many aspects of human behaviour are remarkably stable across times, places and situations. Repetition and predictability also characterises our geographical behaviour. Prior research has confirmed that criminal behaviour is no exception. Offenders tend to recidivate, and recidivists tend to be behaviourally consistent in many aspects, including geographical ones. The present study assesses directional consistency in offending. It reviews the literature on directional consistency. It proposes an improved measure of directional consistency, and empirically uses this measure to explore directional consistency amongst a set of 268 burglars in The Hague. Copyright © 2012 John Wiley & Sons, Ltd.     

Co‐offending and the choice of target areas in burglary

Using data on residential burglaries and residential burglars in The Hague, this study addresses the issue of whether solitary offenders choose their target areas differently from the way offender groups do. It is hypothesised that, in general, burglars are attracted to neighbourhoods that are nearby their homes, nearby the city centre, affluent, physically accessible, and characterised by social disorganisation. In addition, differences between solitary burglars and co‐offending burglar groups regarding the strength of these criteria are assessed. The results support the postulated relevance of physical accessibility and proximity to the offenders' homes for both single offenders and co‐offending groups. However, solitary burglars and burglar groups seem to agree on what constitutes an attractive target area, because no evidence for the postulated differences between them is found. Copyright © 2006 John Wiley & Sons, Ltd.     

Serial murderers' spatial decisions: factors that influence crime location choice

The outcome of German serial murderer spatial decision making was measured as the straight‐line distance (km) between murderer home locations and each crime location (i.e. body recovery location). Geographic and series development data, as well as information on age, intelligence, motive, marital status, employment status, and mode of transportation of 53 German serial murderers was collected from police and prosecution service files and judicial verdict records. Potential effects of the aforementioned factors on spatial decisions were assessed. Results showed that 63% of the murderers lived within 10 km of their crime locations. Home‐to‐crime distance was negatively correlated with murderer age and positively correlated with murderer IQ score. Results also showed that the mode of transportation used by murderers had an effect on their spatial decisions. Results are discussed in terms of understanding serial murderer spatial decision‐making and implications for police investigations. Copyright © 2005 John Wiley & Sons, Ltd.     

Individual differences in visual imagery determine how event information is remembered

Individuals differ in how they mentally imagine past events. When reminiscing about a past experience, some individuals remember the event accompanied by rich visual images, while others will remember it with few of these images. In spite of the implications that these differences in the use of imagery have to the understanding of human memory, few studies have taken them into consideration. We examined how imagery interference affecting event memory retrieval was differently modulated by spatial and object imagery ability. We presented participants with a series of video-clips depicting complex events. Participants subsequently answered true/false questions related to event, spatial, or feature details contained in the videos, while simultaneously viewing stimuli that interfered with visual imagery processes (dynamic visual noise; DVN) or a control grey screen. The impact of DVN on memory accuracy was related to individual differences in spatial imagery ability. Individuals high in spatial imagery were less accurate at recalling details from the videos when simultaneously viewing the DVN stimuli compared to those low in spatial imagery ability. This finding held for questions related to the event and spatial details but not feature details. This study advocates for the inclusion of individual differences when studying memory processes.     

Individual differences in the emotional modulation of gaze-cuing

Gaze-cuing refers to the spontaneous orienting of attention towards a gazed-at location, characterised by shorter response times to gazed-at than non-gazed at targets. Previous research suggests that processing of these gaze cues interacts with the processing of facial expression cues to enhance gaze-cuing. However, whether only negative emotions (which signal potential threat or uncertainty) can enhance gaze-cuing is still debated, and whether this emotional modulation varies as a function of individual differences still remains largely unclear. Combining data from seven experiments, we investigated the emotional modulation of gaze-cuing in the general population as a function of participant sex, and self-reported subclinical trait anxiety, depression, and autistic traits. We found that (i) emotional enhancement of gaze-cuing can occur for both positive and negative expressions, (ii) the higher the score on the Attention to Detail subscale of the Autism Spectrum Quotient, the smaller the emotional enhancement of gaze-cuing, especially for happy expressions, and (iii) emotional modulation of gaze-cuing does not vary as a function of participant anxiety, depression or sex, although women display an overall larger gaze-cuing effect than men.     

Individual differences in visual acuity and face matching ability

The visual acuity of the eyes varies outside the range of normal vision, requiring corrective lenses, but also within the normal range. This study investigated whether both types of variation relate to individual differences in face-identity matching, considering this applied task requires perception of detail. Across two experiments, face-matching accuracy correlated with variation in acuity when this fell outside the normal range of vision and was uncorrected with glasses or contact lenses. In contrast, variation in visual acuity within the normal range did not affect face-matching accuracy, whereas matching accuracy at a given level of acuity could vary substantially. These results indicate that visual acuity is only a problem for occupations performing face-identity matching when below-normal acuity is not diagnosed or adequately corrected. In turn, these findings suggest that variation in acuity within the normal range is not a contributing factor to individual differences in face matching accuracy.     

Individual differences, intelligence, and behavior analysis

Despite its avowed goal of understanding individual behavior, the field of behavior analysis has largely ignored the determinants of consistent differences in level of performance among individuals. The present article discusses major findings in the study of individual differences in intelligence from the conceptual framework of a functional analysis of behavior. In addition to general intelligence, we discuss three other major aspects of behavior in which individuals differ: speed of processing, working memory, and the learning of three-term contingencies. Despite recent progress in our understanding of the relations among these aspects of behavior, numerous issues remain unresolved. Researchers need to determine which learning tasks predict individual differences in intelligence and which do not, and then identify the specific characteristics of these tasks that make such prediction possible.     

Individual differences in children's emotion understanding: effects of age and language

Over the last two decades, it has been established that children's emotion understanding changes as they develop. Recent studies have also begun to address individual differences in children's emotion understanding. The first goal of this study was to examine the development of these individual differences across a wide age range with a test assessing nine different components of emotion understanding. The second goal was to examine the relation between language ability and individual differences in emotion understanding. Eighty children ranging in age from 4 to 11 years were tested. Children displayed a clear improvement with age in both their emotion understanding and language ability. In each age group, there were clear individual differences in emotion understanding and language ability. Age and language ability together explained 72% of emotion understanding variance; 20% of this variance was explained by age alone and 27% by language ability alone. The results are discussed in terms of their theoretical and practical implications.     

Individual differences in processing styles: validity of the Rational-Experiential Inventory

In Study 1 (N= 203) the factor structure of a Swedish translation of Pacini and Epstein's Rational-Experiential Inventory (REI-40) was investigated using confirmatory factor analysis. The hypothesized model with rationality and experientiality as orthogonal factors had satisfactory fit to the data, significantly better than alternative models (with two correlated factors or a single factor). Inclusion of "ability" and "favorability" subscales for rationality and experientiality increased fit further. It was concluded that the structural validity of the REI is adequate. In Study 2 (N= 72) the REI-factors were shown to have theoretically meaningful correlations to other personality traits, indicating convergent and discriminant validity. Finally, scores on the rationality scale were negatively related to risky choice framing effects in Kahneman and Tversky's Asian disease task, indicating concurrent validity. On the basis of these findings it was concluded that the test has satisfactory psychometric properties.     

Individual differences in proactive interference in verbal and visuospatial working memory

Proactive interference (PI) has been shown to affect working memory (WM) span as well as the predictive utility of WM span measures. However, most of the research on PI has been conducted using verbal memory items, and much less is known about the role of PI in the visuospatial domain. In order to further explore this issue, the present study used a within-subjects manipulation of PI that alternated clusters of trials with verbal and visuospatial to-be-remembered items. Although PI was shown to build and release across trials similarly in the two domains, important differences also were observed. The ability of verbal WM to predict performance on a measure of fluid intelligence was significantly affected by the amount of PI present, consistent with past research, but this proved not to be the case for visuospatial WM. Further, individuals’ susceptibility to PI in one domain was relatively independent of their susceptibility in the other domain, suggesting that, contrary to some theories of executive function, individual differences in PI susceptibility may not be domain-general.     

Individual differences in 10‐month‐olds' performance on the A‐not‐B task

This study used the classical A‐not‐B task (Piaget, 1954 ) to explore individual differences in cognitive flexibility in 10‐month‐old infants by: (1) examining how differences in search performance during A trials relate to search performance during B trials; (2) studying the relation between temperamental dimensions and A‐not‐B performance; and (3) investigating differences in search performance between looking and reaching responses within the same task. Forty infants were tested on a fixed‐design‐version of the A‐not‐B task, not allowing for training or individual adjustment, but instead eliciting additional search behaviors than the common correct responses in A trials and perseverative errors in B trials. Infants were also rated by their parents on the temperamental scales Activity level and Attention span. The main findings were: (1) performance on A trials affected B trial performance, with infants being more correct on A trials having more incorrect and less ‘no search’ responses on B trials; (2) activity level, but not attention span, was related to performance on the A‐not‐B task, with infants performing better on A trials having a lower activity level; and (3) there were a few differences in performance with regard to modality, indicating that responding correctly by looking may be less cognitively demanding than doing so by reaching. This study demonstrated that 10‐month‐olds show a wide variation of search behaviors on this A‐not‐B task, resulting in individual differences in performance. These differences are suggested to reflect variation in temperamental activity level as well as maturity of short term/working memory, inhibition and cognitive flexibility.     

The consistency of inconsistency in serial homicide: patterns of behavioural change across series

Linkage analysis is a crucial part of the investigative process when faced with a possible series of related offences. Establishing behavioural consistency (i.e., offender's behaviours consistently present across the series) is at the core of linkage. Recent empirical studies have found little evidence of consistency looking at either individual or groups of behaviours in serial homicide. It is argued that behavioural changes are rooted in the changing cognitive strategies that offenders use to reach their ultimate goal (i.e. the commission of multiple homicides). Factors that could account for these changes include learning, situational factors, loss of control, and changes in the offender's fantasy. Patterns of behavioural change have been identified in serial crimes, such as rape. However, no empirical studies have looked at patterns of behavioural change in serial homicide. The present study examined patterns of consistency and change using a combination of thematic and behavioural subgroup approaches that use Multidimensional Scaling. Thematic differentiation indicative of behavioural manifestations of cognitive strategies was found in all three examined subgroups: planning, wounding, and offender–victim interaction, and patterns of change within these subgroups provided support for the above theories. Looking at behavioural patterns rather than individual behaviours, may be a more fruitful way of examining consistency in serial homicide, and could have significant implications for linkage analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

Individual differences in visuospatial working memory: benefits from environmental support for rehearsal

ABSTRACT

Previous research has suggested that participants with low working memory spans are less likely than those with high spans to engage in rehearsal and other effective strategies during memory tasks. However, most of this research has been conducted in the verbal domain, and less is known about strategy differences in visuospatial working memory. Therefore, the present experiments investigated potential individual differences in the benefit participants receive from environmental support for visuospatial rehearsal. In Experiment 1, memory spans were significantly larger when support was present (i.e. when the array of possible locations remained on the screen) during long inter-item intervals, but importantly, the observed benefit was larger for high-span participants than low-span participants, suggesting that high spans were more likely to use support to facilitate their rehearsal. Other research has suggested that low spans may benefit more than high spans from rehearsal instructions, and so in Experiment 2, participants also were provided with such instructions. However, the rehearsal instructions did not improve memory spans significantly in either group, suggesting that low spans are not only naturally less strategic than high spans, but they may be less capable of taking advantage of effective rehearsal strategies, even when environmental support is present.     

Individual differences in episodic memory abilities predict successful prospective memory output monitoring

Output monitoring refers to memory for one’s previously completed actions. In the context of prospective memory (PM) (e.g., remembering to take medication), failures of output monitoring can result in repetitions and omissions of planned actions (e.g., over- or under-medication). To be successful in output monitoring paradigms, participants must flexibly control attention to detect PM cues as well as engage controlled retrieval of previous actions whenever a particular cue is encountered. The current study examined individual differences in output monitoring abilities in a group of younger adults differing in attention control (AC) and episodic memory (EM) abilities. The results showed that AC ability uniquely predicted successful cue detection on the first presentation, whereas EM ability uniquely predicted successful output monitoring on the second presentation. The current study highlights the importance of examining external correlates of PM abilities and contributes to the growing body of research on individual differences in PM.