Do the Ages of Mass Shooters Matter? Analyzing the Differences Between Young and Older Offenders

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As the threat of public mass shootings continues to be on the forefront of Americans’ minds, it begs the question whether there are differences between young and older mass shooters. In general, earlier research suggests that young people are more likely than their older counterparts to commit crimes because of immaturity, lack of impulse control, rebelliousness, peer pressure, poor role models, and the influence of what they see on television or consume through other media content. When it comes to mass shooters, however, the answer to this question may depend on whether ‘‘young’’ offenders are defined using the legal age of adulthood or the scientific definition of when brain development typically reaches maturity. This study aims to determine whether significant differences exist between public mass shooters who were younger than or older than 18 years when they attacked, or younger than or older than 25 years when they attacked, by examining 88 offenders who struck in the United States from January 1982 to March 2018. Tests of statistical significance suggest that with both definitions, young mass shooters are more likely than older mass shooters to obtain their weapons illegally, attack at schools, have a reported history of animal abuse, and admit copying or being inspired by previous attackers. These results are interpreted in the context of previous scholarship, and recommendations are provided for future research.

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... Many unknowns remain about the causes and prevention of these events. Mass shootings are a challenging type of crime to research due to their inherent heterogeneity (Fox & Levin, 2017;Lankford, 2015;Lankford & Hoover, 2019). Mass shootings are also rare events that involve only a handful of perpetrators, many of whom are ultimately killed or commit suicide shortly after the incident (Lankford, 2015). ...
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... According to recent statistics [37], most of the past shooting attacks were carried out by male offenders, while data [38] also shows that they often used handguns as weapons. Another recent study [39] shows that young mass shooters are more likely than older. The design of the developed SG took into account these observations; hence the virtual shooter was assumed to be a young male armed with a handgun, as shown in Figure 4. ...
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Objective: Model the global distribution of public mass shooters around the world. Method: Negative binomial regression is used to test the effects of homicide rates, suicide rates, firearm ownership rates, and several control variables on public mass shooters per country from 1966 to 2012. Results: The global distribution of public mass shooters appears partially attributable to cross-national differences in firearms availability but not associated with cross-national homicide or suicide rates. Conclusion: The United States and other nations with high firearm ownership rates may be particularly susceptible to future public mass shootings, even if they are relatively peaceful or mentally healthy according to other national indicators.
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Previous research suggests that there are fundamental psychological and behavioral differences between offenders who commit murder and offenders who commit murder-suicide. Whether a similar distinction exists for rampage, workplace, and school shooters remains unknown. Using data from the 2010 NYPD report, this study presents results from the first regression analysis of all qualifying mass shooters who struck in the USA between 1966 and 2010 (N = 185). Findings suggest that there are fundamental differences between mass shooters who die as a result of their attacks and mass shooters who live. Patterns among offenders, the weapons they use, the victims they kill, and the locations they attack may have significant implications for scholars and security officials alike.
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Mass murder—the sudden, explosive killing of a group of people—when committed by adults often is followed by the offender committing suicide. Recently in the United States, frequent cases of mass murder are reported as committed by adolescents. However, among juvenile mass murderers, there are no reported suicides (or attempts) by the offenders. This article provides a typology of mass murderers and offers a dynamic interpretation of the development of conscience and moral decisional capacity in adult and juvenile offenders. Preventive measures are explored along with methodological techniques that may distinguish between adult and juvenile mass murderers in their propensity to commit suicide after the events.
One of the few facts agreed on in criminology is the age distribution of crime. This fact has been used to criticize social theories of crime causation, to provide the foundation for other theories, to justify recent emphases on career criminals, and to support claims of superiority for longitudinal designs in criminological research. In the present paper, we argue that the age distribution of crime is sufficiently invariant over a broad range of social conditions that these uses of the age distribution are not justified by available evidence.
Peer influence is regarded as one of the strongest determinants of juvenile delinquency and particularly adolescent substance use. A commonly held view is that social pressure from friends to use drugs and alcohol is a major contributor to substance use. Yet the notion of peer pressure, implied by the association between peer-group associations and drug behavior, is seldom tested empirically. As a crucial test of the group pressure model, this research examines the role of peer pressure in mediating the effect of differential association on individual use. Moreover, few studies examine the nature of the relationship between peers and substance use as it relates to the processes leading toand from use. Drawing on differential association and social learning theories, our research specifies the social processes (socialization, group pressure, social selection, and rationalization) which dictate particular causal pathways leading to and from substance use and then estimates the reciprocal influences among differential association, social pressure from peers, attitudes favorable toward substance use, and individual use. Using the 1977–1979 National Youth Survey panel data, we estimate a covariance structural equation model allowing for correlated measurement error. In the cross-sectional analyses, we find no main effects of overt peer pressure on substance use. Estimation of the reciprocal effects model also reveals that overt peer pressure does not significantly influence substance use and does not mediate the effect of differential association. Instead, the influences of socialization, social selection, and rationalization play significant roles in understanding substance use.
The prevalence of antisocial and delinquent behavior in juveniles has increased dramatically over the past decades, along with the prevalence of other health-endangering behaviors, such as substance use and suicide. These trends have been accompanied by increased levels of psychiatric admissions and special classroom placements in schools. It is posed that these changes reflect decreased levels of impulse control by children living in the U.S. This paper focuses on impulse control as it relates to antisocial and delinquent behavior in juveniles. It traces the development of these behaviors through their age-specific manifestations, and summarizes known social and biological risk factors. The paper examines how different risk factors impinge on the development of antisocial behavior at different points in the life cycle. Developmental sequences are reviewed leading to serious antisocial behavior or to assistance of the behavior. The interaction between developmental tasks and the emergence of antisocial behavior is considered. Critical, “sensitive” periods in development often intersect with the increased prevalence of risk factors at certain age periods of children, leading to the emergence or aggravation of antisocial behavior. The use of empirical developmental knowledge for screening of population of youngsters is highlighted. The paper closes by reviewing how treatment and preventive studies are affected by pre-existing risk factors, and then lists priority areas for future survey and process studies, and for improved intervention efforts.
The age specificity of time-space clusters of suicide was examined using National Center for Health Statistics data for 1978-84. Significant clustering of suicide occurred primarily among teenagers and young adults, with minimal effect beyond 24 years of age. Clustering was two to four times more common among adolescents and young adults than among other age groups.
Thirty adult mass murderers and 34 adolescent mass murderers in North America are compared on both offender and offense variables to delineate similarities and differences. Findings indicate a plethora of psychiatric disturbances and odd/reclusive and acting-out personality traits. Predisposing factors include a fascination with weapons and war among many of the adolescents and the development of a "warrior mentality" in most of the adults. Precipitating factors indicate a major rejection or loss in the hours or days preceding the mass murder. Results are interpreted through the lens of threat assessment for targeted violence (Borum, Fein, Vossekuil, & Bergland 1999), recognizing that a fact-based, dynamic behavioral approach is most useful for mitigating risk of such an extremely low-base-rate violent crime.
Prior research describes the development of susceptibility to peer pressure in adolescence as following an inverted U-shaped curve, increasing during early adolescence, peaking around age 14, and declining thereafter. This pattern, however, is derived mainly from studies that specifically examined peer pressure to engage in antisocial behavior. In the present study, age differences and developmental change in resistance to peer influence were assessed using a new self-report instrument that separates susceptibility to peer pressure from willingness to engage in antisocial activity. Data from four ethnically and socioeconomically diverse samples comprising more than 3,600 males and females between the ages of 10 and 30 were pooled from one longitudinal and two cross-sectional studies. Results show that across all demographic groups, resistance to peer influences increases linearly between ages 14 and 18. In contrast, there is little evidence for growth in this capacity between ages 10 and 14 or between 18 and 30. Middle adolescence is an especially significant period for the development of the capacity to stand up for what one believes and resist the pressures of one's peers to do otherwise.
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