Psychology of Criminal Behaviour: A Canadian PerChapter 7: Violent Offending: General Violence and Homicide
CHAPTER 7: Violent Offending: General Violence and Homicide
1. Review the prevalence and characteristics of violent offending as well as
consequences for victims.
2. Cover some of the major theories of aggression.
3. Introduce some of the key assessment instruments used to estimate risk of violent
recidivism and examine their predictive accuracy.
4. Examine the effectiveness of treatment in reducing violent recidivism.
5. Review the prevalence and characteristics of homicide and describe different types of
CHAPTER SUMMARY : General Violence
Violence is relatively rare in Canada. The rate of violent crime has generally decreased
since the early 1990s. Only about one-third of violent incidents are reported to the
police. Being young, being single, often going out in the evening, and living in cities
are associated with higher rates of violent victimization.
Hostile aggression is an impulsive reaction to some real or perceived provocation or
threat, whereas instrumental aggression is premeditated and ultimately aimed at
achieving some secondary goal. Hostile and instrumental aggression may be best
viewed as opposite ends of a continuum along which acts of aggression can fall.
Four key approaches to risk assessment are unstructured clinical judgment, empirical
actuarial, mechanical, and structured professional judgment. Actuarial risk-assessment
instruments (e.g., VRAG, SAQ) are generally more accurate at predicting violent
recidivism than structured professional judgment instruments and unstructured clinical
In violence risk assessment, different predictive errors have different consequences.
False positives result in unnecessarily restricting offenders’ liberty and wasting scarce
resources, whereas false negatives result in harm to those who are victimized by the
offender. The optimal balance between the two types of errors will vary depending on
the relative costs and benefits of each outcome.
Researchers generally find lower violent recidivism rates among treated compared to
untreated offenders, and programs that follow the general principles of effective
corrections appear to be more effective than programs that do not. Although these
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findings are very encouraging, debate continues about whether the lower rates of
violent recidivism associated with treatment actually demonstrate that it is effective
because the research methodology used in most studies leaves the results open to
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Homicide rates are quite low in Canada compared to many other countries.
Perpetrators and victims are more likely to be male than female. Victims are most
likely to be killed by someone they know. Multiple murders, such as mass murder,
spree murder, and serial murder, are exceedingly rare.
In this chapter we will review the prevalence and characteristics of
violence in Canada.
We will also present some theories of violent behaviour, the major
approaches to risk assessment, some of the more established risk
assessment instruments, and research on the predictive accuracy of these
Research on the effectiveness of treatment programs for violent offenders
will also be reviewed.
Finally, homicide, the most extreme form of violence, will be examined.
2. Defining Aggression And Violence:
Aggression researchers have provided useful definitions of aggression and
The terms have a considerable degree of overlap, but they are not
Human aggression has been defined as “any behavior directed towards
another individual that is carried out with the proximate (immediate) intent
to cause harm.
the perpetrator must believe that the behavior will harm the target, and that
the target is motivated to avoid the behavior”
Violence has been defined as “aggression that has extreme harm as its goal
Prevalence of Violence
Violent crime accounts for approximately one in eight criminal incidents
The rate of violent crime reported to the police (Uniform Crime
Reporting Survey) in 2007 was 930 per 100 000 people.
This rate has decreased since the early 1990s.
in 2007, the lowest rate was in Ontario (5228 per 100 000 people) and the
highest was in Saskatchewan (13 225 per 100 000 people)
Robbery is often considered a violent offence because it involves at the
very least an implied threat of violence.
The robbery rate for Canada in 2007 was 90 per 100 000 people.
In 2007, 11 percent of all robberies in involved a firearm, whereas 60
percent involved no weapon. Of all Canadian provinces, PEI had the
lowest rate of robbery in 2007 (11 per 100 000 people) and Manitoba had
the highest (179 per 100 000 people).
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Robbery rates have decreased since the early 1990s - This is the case for
armed robbery involving a firearm or some other weapon.
robbery without a weapon has increased slightly.
In contrast to decreases observed in other types of crime, violent crime by
youth (aged 12 to 17) has increased fairly steadily over the past 20 years -
the rate of violent crime reported by youth in 2007 was 6811 per 100 000
Crime reported to the police is an underestimate of the actual number of
For a variety of reasons, some violent incidents do not come to the
attention of the authorities.
The General Social Survey (GSS) on Victimization reflects reports from
the Canadian population aged15 and older on their criminal victimization.
According to the most recent GSS (2004), only 33 percent of violent
incidents were reported to the police
The reporting rates were highest for robbery (46 percent), followed by
physical assaults (39 percent) and sexual assaults (8 percent).
There are a number of reasons why victims may or may not report violent
Reporting to the police was more likely in incidents involving physical
injury (47 percent) compared to no physical injury (28 percent), and for
incidents involving weapons (53 percent) compared to no weapons (25
The most common reasons given for not reporting crimes were that:
1. the victim dealt with the incident in another way (60 percent),
2. it was not important enough (53 percent),
3. did not want police involved (42 percent),
4. felt it was a personal matter (39 percent),
5. did not think police involvement could help (29 percent), or
6. for fear of retaliation from perpetrator (11 percent).
The rates of violent victimization did not change dramatically from the
preceding GSS, administered in 1999, to the most current
The rates of violent victimization were quite similar for men and women:
111 per 1000 men versus 102 per 1000 women in 2004
differences between men’s and women’s victimization become apparent
when the type of violence is taken into consideration.
Men were more likely to experience non-sexual violence than women (91
physical assaults per 1000 men versus 59 per 1000 women; 13 robberies
per 1000 men versus 8 per 1000 women), whereas women were more
likely to experience sexual violence than men (35 sexual assaults per 1000
women versus 7 per 1000 men).
Excluding spousal violence, approximately half (51 percent) of the violent
crimes reported were committed by someone known to the victim (e.g.,
friend, acquaintance) and 44 percent were committed by strangers
(Gannon and Mihorean 2005).
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Some characteristics associated with higher rates of violent victimization
are being young, being single, often going out in the evening, and living in
cities. In terms of age, the rate of violent victimization was considerably
higher among 15- to 24-year-olds than older people in Canada.
the rate of violent victimization among people aged 15 to 24 was 226 per
Among those aged 25 to 34, it was 157 per 1000 people.
The rate of violent victimization continues to drop with increasing age.
For those aged 55 to 64, the rate drops to 45 per 1000 people.
Among single people, the rate of violent victimization was 203 per 1000,
whereas among married people it was 52 per 1000 people.
In terms of evening activities, the rate of violent victimization was 174 per
1000 people among those who engaged in many evening activities (30 or
more per month) versus 44 per 1000 people for those who engaged in
relatively few evening activities (less than 10 per month).
Evening activities include things like going to bars or visiting friends.
The rate of victimization for those living in urban areas was 112 per 1000
people, compared to 84 per 1000 people living in rural areas.
Consequences for Victims
In 2004, 25 percent of violent crimes resulted in physical injury to victims
Separated by type of violence, 7 percent of sexual assaults, 30 percent of
robberies, and 31 percent of physical assaults resulted in physical injury to
In 25 percent of violent crimes, victims reported that the crime caused
them to have difficulty functioning in their everyday activities.
some common emotional reactions were anger; feeling upset, confused, or
frustrated; and feeling fearful.
Hostile versus Instrumental Violence
Aggression can take different forms, serve different purposes, and have
One major distinction that is receiving increasing research attention is
between hostile aggression , (there is little if any forethought and
planning, the assault is in response to provocation, and the primary goal is
to harm the other), which is an impulsive reaction to some real or
perceived provocation or threat, and instrumental aggression, which is
premeditated and aimed at achieving some secondary goal
Hostile aggression has also been referred to as affective, impulsive,
reactive, emotional, and expressive aggression.
Instrumental aggression is generally similar to predatory, premeditated, or
Although there are some subtle differences between these terms, they
generally reflect the distinctions:
both hostile and instrumental aggression as characterized by the
intention to harm at the proximate level, and differing in their goals
primarily at the ultimate level.
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Operationally defining hostile and instrumental aggression can be
Some acts of aggression may have elements of both types.
The Instrumental Aggression Rating Measure to assess the extent to which
violence is instrumental versus hostile:
1. Planning or preparation before the aggression
2. Goal directed—the act helped obtain a specific and identifiable goal
3. The aggressive behaviour was unprovoked by the victim
4. Lack of anger during the aggression
5. The victim of the aggression was a stranger
Higher ratings on these items would be associated with instrumental
hostile and instrumental aggression may be best viewed as opposite ends
of a continuum along which acts of aggression can fall.
Violence may be completely hostile, completely instrumental, or fall
somewhere in between.
3. Explaining Violence:
Social Learning Theory
Social learning theory (Bandura 1973) holds that aggression is learned
The main tenet is quite simple and parsimonious: aggression is more likely
to occur when it is expected to be more rewarding than non-aggressive
As Bandura (1973: 2) noted:
Concern over the adverse consequences of aggression obscures the
fact that such behaviour often has functional value for the user.
there is a property unique to aggression that generally creates
conditions fostering its occurrence.
Unlike other social behaviors that cannot be effective without some
reciprocity acceptable to the participants, aggression does not require
willing responsiveness from others for its success.
One can injure and destroy to self-advantage regardless of whether
the victim likes it or not.
By aggressive behaviour, or dominance through physical and verbal
force, individuals can obtain valued resources, change rules to fit
their own wishes, gain control over and extract subservience from
others, eliminate conditions that adversely affect their well-being,
and remove barriers that block or delay attainment of desired goals.
Thus, behaviour that is punishing for the victim can, at least on a
short-term basis, be rewarding for the aggressor.
expected outcomes influence the likelihood and extent of aggressive
In operant conditioning, behaviour is shaped by its consequences; that is,
reinforcement or punishment.
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Reinforcement increases the likelihood that a given behaviour will occur,
whereas punishment decreases the likelihood of its occurrence.
Adding to the familiar concept of operant conditioning, Bandura (1973)
argued that people learn not only from direct experience, but also from
observing the behaviour of others and the outcomes of others’ behaviour.
Observing others receiving various rewards for their aggression would
increase the chance that one would engage in similar forms of aggression.
In contrast, observing others receiving punishment for their aggression
would decrease the likelihood that one would engage in similar forms of
The self is also an important source of reinforcement.
Self-reinforcement refers to the influence of self-administered rewards or
punishments for aggression.
If self-evaluation following aggression is positive, aggression would be
more likely than if self-evaluation is negative
Reinforcers influence aggressive behaviour and are mediated by cognition,
such as one’s attention, perception, memory, and resulting expectancies
General Aggression Model (GAM)
The General Aggression Model (GAM) is an integration of a number of
smaller, more specific theories of aggressive behaviour.
the GAM describes the processes involved in any one episode among an
ongoing series of episodes of a social encounter.
The main components are inputs from the person and situation, the routes
(cognitive, affective, and arousal states) that mediate the influence of
inputs, and the appraisal and decision processes that lead to a particular
action in the episode.
The outcome influences the social encounter, which then provides inputs
in the next episode.
Person inputs, such as traits, gender, beliefs, attitudes, values, long-term
goals, and behavioural scripts, refer to relatively stable characteristics that
individuals bring to any given situation and can predispose one toward or
Situational inputs can also influence aggression in a given episode.
Such factors include aggressive cues, provocation, frustration, pain and
discomfort, drugs, and incentives.
The routes through which person and situation inputs influence aggression
are cognitive, affective, and arousal states.
Cognitive states include hostile thoughts and behavioural scripts.
Affective states include mood and emotion as well as expressive motor
Arousal can influence aggression in a number of ways: high levels of
physiological arousal preceding a provocation can be mislabelled as anger,
thereby increasing aggressive behaviour.
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Cognition, affect, and arousal are all interconnected in the GAM and each
may influence the other.
Some of the variables may seem to overlap between inputs and routes:
scripts are listed as both a person factor and a cognitive state.
scripts as a person factor refer to a relatively stable characteristic (i.e., the
presence and level of activation of such a script typical of a given person),
whereas scripts as a cognitive state refer to the degree to which a
particular behavioural script is activated in a particular situation.
Evolutionary Psychological Perspective
In ancestral environments certain physiological, psychological, and
behavioural characteristics were associated with increased reproductive
success (i.e., having a relatively high number of children who in turn have
a relatively high number of children, and so on)
To the extent that such characteristics are heritable, the genes responsible
for them would be passed on to subsequent generations more so than
genes that are responsible for characteristics associated with reproductive
Building on research and theory on general antisocial behaviour, experts
propose that most violent people fall in one of three groups: young men,
competitively disadvantaged men, or psychopaths.
Adolescent and young men typically have relatively few resources
and low status, which puts them at a competitive disadvantage
relative to other males with whom they are competing for resources
Through violence and general risk taking, these young men may be
able to increase their status, resources, and/or access to more and
as they move into adulthood and begin to acquire legitimately gained
resources and status, the costs of violence begin to outweigh the
benefits, so they switch from short-term high-risk strategies to more
long-term lower-risk strategies.
So the violent behaviour of this group is limited to adolescence and
This is the most common type of violent offender.
This desistance with adulthood, however, does not occur for the
competitively disadvantaged men.
Their violent behaviour is life-course persistent.
The ability to compete for resources and status in prosocial ways is
impaired by early neurodevelopmental insults, such as obstetrical
complications and low IQ.
Because men in this group do not have the skills or abilities to
achieve status and resources in prosocial ways, they maintain their
high-risk approach into adulthood.
The final group, psychopaths, are also life-course-persistent.
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In contrast to the competitively disadvantaged men, psychopaths are
not competitively disadvantaged but select short-term high-risk
strategies as an alternate approach.
Competitively disadvantaged men and psychopaths are thought to
make up a relatively small proportion of violent individuals.
4. Risk Assessment:
Compared to general criminal recidivism, violent recidivism is less
in a meta-analysis of recidivism of mentally disordered offenders,
researchers found an average violent recidivism rate of 24.5 percent and a
general recidivism rate of 45.8 percent over a mean follow-up period of
A similar rate of violent recidivism was reported for non-mentally
disordered offenders in a metaanalysis, with 21.73 percent over a follow-
up period of approximately 2 to 5 years.
Although most violent offenders do not violently recidivate, it is possible
to identify subgroups with relatively high rates of violent recidivism.
Approaches to risk assessment can be categorized in a number of ways.
Four key categories are: unstructured clinical judgment; empirical
actuarial; mechanical; and structured professional judgment
Unstructured clinical judgment involves arriving at an estimate of risk
based on the assessor’s own idiosyncratic decisions about what factors to
consider and how to combine those factors.
In contrast, the empirical actuarial and mechanical instruments both follow
explicit rules about what factors to consider and how to combine those
factors to arrive at a final estimate of risk.
two characteristics distinguish empirical actuarial from mechanical.
For empirical actuarial instruments:
1. the selection and combination of items are derived from their
observed statistical relationship with recidivism; and
2. tables linking scores to expected recidivism rates are provided.
For mechanical instruments, the selection and combination of items are
derived from theory or reviews of the empirical literature and no tables are
Structured professional judgment incorporates features of both
unstructured clinical judgment and the actuarial approach; there are
explicit guidelines for which factors to consider (although additional
factors may also be considered), but the combination of those factors is
left up to the discretion of the assessor.
Violence Risk Appraisal Guide (VRAG) The Violence Risk Appraisal
Guide is an empirical actuarial risk-assessment instrument designed to
estimate risk for violent recidivism.
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It was developed with a sample from a maximum-security forensic
psychiatric institution in Penetanguishene, Ontario.
Violent recidivism was operationally defined as a new charge for
violent offence, which included homicide, attempted homicide,
kidnapping, forcible confinement, wounding, assault, armed robbery,
and contact sex offences (e.g., rape, child molestation).
The VRAG consists of 12 static items that were selected from an
initial pool of approximately 50 variables.
The final 12 items are those that made the strongest independent
statistical contribution to predicting violent recidivism.
The Scores are grouped into nine risk categories (or bins), each
containing seven points.
Focusing on the extremes, none of the patients who scored in the
lowest VRAG risk category violently recidivated, whereas all the
patients who scored in the highest risk category violently
HCR-20 Violence Risk Assessment Scheme is a structured professional
judgment instrument designed to assess risk for violence.
It consists of ten historical items, five clinical items, and five risk
The historical items, which are static and reflect the past, include
previous violence, young age at first violent incident, relationship
instability, employment problems, major mental illness,
psychopathy, early maladjustment, personality disorder, and prior
The clinical items, which are dynamic and reflect current
functioning, include lack of insight, negative attitudes, active
symptoms of major mental illness, impulsivity, and unresponsive to
The risk management items, which concern future circumstances that
may be encountered in the institution or community that could