Laura Hammond

Prioritizing Burglars: Comparing the Effectiveness of Geographical Profiling Methods

The effectiveness, in prioritizing suspects, of six geographical profiling methods are compared by determining the rank to which each of 92 prolific burglars was assigned, from the total of 400 known burglars, who were selected from a large metropolitan database because they resided in the borough in which the crimes occurred. Using mean and median ranked prioritization of actual offenders, as well as the percentages that appeared in the top 5% of rankings and the area under the curve of a specially developed ‘Ranked Prioritization Function,’ RP (f), it was found that Dragnet using a logarithmic decay function and the distance from the centre of gravity produced the lowest average ranks, with 72% of the actual offenders in the top 5% of prioritized rankings. The implications of the findings are discussed.

A model for differentiating school shooters characteristics

Purpose – The purpose of this paper is to explore the potential for developing a model for differentiating school shooters based on their characteristics (or risk factors) before the attack took place. Design/methodology/approach – Data on 40 school shootings was compiled from the National School Safety Center’s Report on School Associated Violent Deaths and media accounts. Content analysis of the cases produced a set of 18 variables relating to offenders’ characteristics (or risk factors). Data were subjected to Smallest Space Analysis (SSA), a non-metric multidimensional scaling procedure. Findings – Results revealed three distinct themes: Disturbed School Shooter, Rejected School Shooter and Criminal School Shooter. Further analysis identified links between these themes with the family background of the offender. Research limitations/implications – These findings have both significant theoretical implications in the understanding of school shooters and the crime in general. They offer potential for pra...

The changing face of homicide research: the shift in empirical focus and emerging research trends

Purpose – Homicidal behaviour is influenced by a complex interaction of behavioural, situational and environmental factors that raise many challenging psychological questions. A large and continually growing body of research has explored the crime of homicide, its epidemiology, victims and perpetrators. The area is developing rapidly, opening up new avenues of study. The paper aims to discuss these issues. Design/methodology/approach – This special issue of the Journal of Criminal Psychology brings together an exciting array of papers on homicidal behaviour, examining a wide range of issues including juvenile homicide perpetrators, school shootings, child homicide, homicide-suicide and differences in offence behaviours and victim characteristics between hard-to-solve one-off homicides and serial homicides. Findings – The range of papers included in this special edition cover a wide range of aspects of homicidal behaviour, reflecting the importance of – and the need for – applied research moving away from ...

Personality Correlates of Co-Witness Suggestibility

ABSTRACT The present study examined the relationship between co-witness suggestibility and individual differences in interpersonal characteristics. Participants (N = 473) took part in an eyewitness simulation, and five independent conditions were used to control for misinformation size. Using confederates, the researchers exposed participants to misinformation about the witnessed event, prior to collecting their statements. The participants then completed the Fundamental Interpersonal Relations Orientation-Behavior assessment (FIRO-B; Schutz, 1958), a measure of expressed and wanted control, affection, and inclusion. Results suggested that the wanted-control dimension was an accurate predictor of co-witness suggestibility. Eyewitnesses who scored highly on wanted control were significantly more likely to accept misinformation from co-witnesses, and were more likely to lose confidence in their own judgments, after a group discussion. In addition, the results suggest that the unanimity of misinformation, but not the size, had a significant influence on co-witness suggestibility.

Age effects on juvenile homicide perpetration

Purpose – In order to address a notable gap in the research literature, the purpose of this paper is to examine age-related differences in juvenile homicide perpetration. Design/methodology/approach – Data on 150 juvenile homicide offenders and their offences was derived from material available within the public domain, including media reports, case studies, court reports and previously published studies. Comparisons were then made between those aged 14 and under (n=63) and those aged 14-17 (n=87) across a range of offender, victim and offence-related variables. Findings – There were no significant differences between the child (U-14) and adolescent (14-17) offender samples on any of the measured variables. The two groups had similar backgrounds, selected similar types of victims, had comparable breakdowns of different types of victim-offender relationship and had similar patterns of weapon use. Research limitations/implications – The fact that the two groups did not differ significantly has notable impli...

A predictive model of criminality in civil psychiatric populations

Purpose – The purpose of this paper is to develop a predictive model of criminal risk in civil psychiatric populations, by determining the relative impacts of psychopathy, drug use, impulsivity and intelligence on levels of criminality. Design/methodology/approach – The sample consisted of 871 civil psychiatric patients, selected from the MacArthur Violence Risk Assessment Study, who had been diagnosed with a mental illness or personality disorder, and hospitalised less than 21 days. Each participant was administered the Hare Psychopathy Checklist Screening Version (PCL:SV), Barratt Impulsiveness Scale (BIS-11) and the Wechsler Adult Intelligence Scale (WAIS-R). In addition, information on background demographics, drug use and criminality was obtained via a self-report questionnaire. Findings – Pearson correlations identified significant positive relationships between past arrests, psychopathy, impulsivity and drug use. Intelligence was negatively related to past arrests. Multiple regressions identified a...

Group size, misinformation and unanimity influences on co-witness judgements

ABSTRACT Researchers have typically observed the effects of co-witness influence on eyewitness pairs. However, research suggests that individuals are more likely to witness crimes in larger groups. Additionally, there is an abundance of evidence suggesting that social influence is heavily moderated by group size. Therefore, the present study aimed to gain a more accurate understanding of the risks of co-witness influence in relation to unanimity and group size effects. Participants (N = 608) viewed and discussed a CCTV footage of a fight breaking out, with co-witnesses, before giving individual statements, where they were asked to identify which person had started the fight; confederates were used to suggest that the wrong man had started the fight. Results indicated that participants were vulnerable to co-witness influence, but only when exposed to misinformation from a majority of co-witnesses. Misinformation presented by an individual confederate did not have a significant influence over the participants’ responses. This study was the first to investigate the effects of group size on blame attribution. The findings suggest that the true risks of co-witness influence may not be as high as originally predicted from research on eyewitness pairs.