Chapter 2 Biological and evolutionary explanations
Theory: an explanation of a particular phenomenon.
A strong theory:
(1) Is parsimonious,
(2) Clearly identifies the causal mechanisms and corresponding mediators and
moderators underlying the phenomenon,
(3) Is testable and falsifiable via hypotheses and predictions,
(4) Is based on empirical data and is modified in response to new data
(5) Posses interdisciplinary compatibility
(6) Respects gender, ethnicity, and culture
– Cesare lombrosso began comparing criminals, men and women as well as
prostitutes to normal segments of the population. Lombrosso argued that
criminals have distinctive physical features and suggested criminals were
– Charles Darwin published On the Origins of species and posited that humans
evolved from ancestral species via the mechanisms of natural selection
Researching Biological explanations of crime
– Neurochemical approaches might examine how genes actually express themselves
in terms of the brains neurotransmitter systems.
– Researchers often define crime using current legal definitions and examine
whether biological factors correlate or predict official criminal offending in the
form of arrests or convictions
– Targets vary such as males vs females, children, adolescents, adults or specific
groups of offenders.
Genetics and Crime – Twins, adoption
– Behavioral genetics relies heavily on the study twins and adoption and can help
separate genetic from environmental influences.
– Every human being shares 99% of his or her DNA sequence with the rest of the
human species however behavioral genetics focuses on the remaining 1% of the
variants that is free vary.
– Monozygotic or identical twins share 100% of their genes. Dizygotic Or fraternal
twins are no more unlike the nontwin siblings.
– The researchers identify a sample of MZM DZ twins. Both raised by the
respective biological families and obtain some estimate of total behavior via self
report or perhaps official records. The researchers report whether each twin was
criminal or noncriminal, then the frequency would be converted into a
concordance rate that represented the percentage of both twins classified as
– Heritability coefficient is a descriptive statistics that represents the proportion of
phenotypic variants in a given behavior in a sample and/or population that can be
attributed to genetic variation among individuals. – Criticisms include that parents are arguably more likely to provide similar
environments for NZ twins then their DZ counterparts, that’s artificially inflating
the genetic contribution. Her ability estimates for MZ twins may be confounded
by prenatal factors that by definition aren’t necessarily genetic.
– Adoption research has two forms one parent offspring adoption studies and to
simply offspring adoption studies. Mednick et al. performed a study and the main
results were that when both biological and adoptive parents had no criminal
record only 13.5% of adopted sons had criminal records; if the adopted parent
had a criminal record and the biological parent did not the percentage increased to
14.7. 20% of adopted sons had a criminal record if the biological but not be
adopted parent also had a criminal record. 24.5% if both sets of parents had
criminal the records.
– Criticisms of adoption studies are the generalizability problems given that
adoptees have a higher rate of antisocial behavior and that the environments of
adopted offspring tend to be more advantageous relative to general population.
– Rhee and Waldman completed another analytic review of twin studies that
resulted in the variance in antisocial behavior as follows: heritability, 0.41; shared
environment, 0.16; and nonshared environment, 0.43. Potential moderators
included zygosity determination, Assessment method, Operational definition of
antisocial behavior, Sex of the participants, and age.
– Genetics and the environment both contribute to variance in antisocial behavior.
Evolutionary theories of crime
– Darwin made two critical points one, species do not always exist in their current
form but evolved or transformed from ancestral species; and two, the other
legionary mechanism for this transformation was not till selections.
– Our ancestral environment was compromised of various selection pressures and
adaptive problems–finding a mate, hunting, gathering, protecting children,
avoiding predators, and find shelter.
– Unsuccessful responses to adaptive problems and/or selection pressures resulted
in death or reduced capacity to reproduce. A successful adaptation–be a biological
or psychological– is housed in an individual’s genetic makeup, so the only way
adaptations can be passed on is through genetics’.
– Given that evolution takes so long, our existing psychological mechanisms are
result of selection pressures that existed during Hunter and gatherer rather than
industrial or even the agricultural revolution.
Life history, Risktaking, and antisocial behavior
– Life history theory argues that natural selection favors allocation strategies that,
on average, optimized reproductive fitness within a given ecological niche.
– Life history theory speaks to three primary tradeoffs. One, focuses on present
versus future reproduction efforts. Second, is the quantity versus quality of
offspring. Third, is the mating effort versus parental investment.
– Life history theory also posits that the optimal allocation strategy will vary as a
function of how many children you already have.
– Natural selection has created psychological mechanisms that weigh the costs and
benefits associated with various resource allocation strategies; is not static, it responds not only to presentday environmental clues but also to age the number
– A group of Canadian researchers has begun using life history theory to explain the
development of two distinct offender groups: life course persistent offenders and
adolescent limited offenders
– Life course persistent offenders begin committing various serious, antisocial acts
prior to adolescent and continue well into adulthood. Adolescent limited offenders
engage in milder forms of antisociality that start in puberty and end in late
– Adolescents are more likely to exhibit high mating effort because in an ancestral
environment it gave them a competitive edge in the reproductive sense. Strong
mating has traits such as dominance, risky behavior, independence, strength,
fearlessness, and physical power
– The reward associated with high mating effort tactics outweighed the cost in an
ancestral environment, and individuals who used high mating efforts more
frequently would have on average produced more offspring and consequently
passed their adaptive psychological mechanism
– Life history theory dictates that individuals will adopt different Life course
strategies depending on environmental cues. Life course persistent offender
suffers from a number of the most likely acquired early in life, perhaps during
pregnancy or childhood.
– Disadvantages accumulate over time and manifest as until neurological or
intellectual deficits that make it difficult to maintain friendships, succeed in
school, or obtain a high status and wellpaying job.
– Embodied capital refers to intrustic abilities such as health, skills, strength, speed,
attractiveness, which translate into enhanced reproductive fitness.
– Psychopathy is typified by a constellation of effective, interpersonal, and
behavioral characteristics, Such as superficial charm, manipulation and lying,
absence of remorse, inability to feel empathy, impulsivity, risktaking behavior
– There are two reasons offending behavior emerges. One is when environmental
insults key one individual that the future is uncertain, That’s directing them to
adopt a high mating effort strategy that encompasses a host of antisocial
behaviors. The second is when individuals are competitively disadvantaged in a
reproductive sense and then they will adopt a high mating effort strategy.
– Polymorphisms is going to a more forms of discrete character exist[Example eye
colour, blood types], The contracting forums are called morphs.
– One way that natural selection maintains diversity of population is through
frequency dependent selection, which states that the reproductive success of her
particular more relative to another mark depends on its frequency.
– It is argued that psychopathic behavior is a morph that has arisen as a direct result
of frequency dependent selection. Psychopaths adopt a high mating effort and it
can be inferred that the particular life history strategy must have been adaptive,
Homicide – Daly and Wilson presented one of the first seminar account of homicide by using
evolution understand various forms homicide– Spousal, blood relative, casual
acquaintance, Revenge killings, And so forth.
– Most homicides occur as a result of altercation arising from arguments, in