Chapter 3 - Origins of criminal behavior: biological factors Flashcards
Aggression and biological/social factors
- Early onset aggressive tendencies: often exhibit biological and neurological abnormalities or deficits
- Late-onset offending appears to be more influenced by social factors
- This leads criminologists to agree that while genetics and biological factors do play a role, social environment is the most important determinant of criminal behavior.
Biopsychologists
psychologists who study the biological aspects of criminal behavior.
Behavior genetics
- focuses on examining the role that genes play in the formation and development of human and animal behavior
- branch of biology that investigates the relationship between genes and the environment in determining individual differences in behavior.
- some methods are used to disentangle genetic from environment influences in twin and adoption studies
Molecular genetics
- field of biology that studies the structure and function of genes at the molecular level.
- focuses on specific genes as foundations for certain patterns of behavior.
- how genes are transferred from generation to generation
Traditional behavior genetic viewpoints
Views behavioral differences as springing from 3 genetic/environmental sources:
1) Influences attributable to genetic effects
2) environmental influences shared by siblings (family/environments)
3) influences that arise from unshared environmental experiences that make siblings differ from one another
Dizygotic (DZ) twins
- also fraternal twins
- develop from two different fertilized eggs
- no more genetically alike than nontwin siblings
- equally susceptible to prenatal environmental influences such as nicotine, alcohol, etc.
Monozygotic (MZ) twins
- also identical twins
- develop from single egg
- always same sex, share 100% of same genes
Monochorionic
MZ twins who share the same chorion, the outer membrane that encloses the embryo, approx. 2/3 of MZ twins are this way. Studies show that MZ, monochorionic twins are more similar in personality and cognitive ability than dichorionic, MZ twins
Dichorionic
MZ twins who have different chorions in utero, approx. 1/3 of MZ twins are this way. As a result they have slightly different prenatal environments, although the difference IS small.
Shared environments
Sometimes referred to as common environments, include prenatal and life experiences affecting both twins in the same way
Nonshared environments
Include living experiences that are different for each twin, such as being raised in a different home environment, participating in different activities, or attending different schools. Research shows nonshared environments account for approx. 30% of the variation in antisocial behavior, although developmental factors of course play a role.
Concordance
A key term in twin research, this is the term used in genetics to describe the degree to which related pairs of subjects both show a particular behavior or condition, and is usually expressed in percentages.
(TEDS) Twins’ Early Development Study
- ongoing, based at King’s College London under Professor Robert Plomin
- explores behavior problems as well as problematic development in language, cognition, and academic abilities from early childhood through adolescence.
Family influences vs. Genetic influences
- studies seem to show that family influences (i.e. positive parenting experiences and familial guidance) have an influence on a child’s aggressive tendencies, BUT the genetic predispositions and factors play an increasing role as the individual grows older, and familial influences play a smaller and smaller role as adolescence and adulthood sets in.
MAOA-L gene
nicknamed “the warrior gene” by some researchers, low activity from this gene has been linked to aggression and violence, and is carried by an estimated 1/3 of the population. Studies show that people with this gene who were also exposed to adverse childhood experiences were more likely to be offenders in late adolescence and adulthood.
Psychophysiology
The study of the dynamic interactions between behavior and the autonomic nervous system
Autonomic arousal theory of crime
hypothesizes that persistent, chronic offenders compared with those with little or no offending history, will exhibit low levels of autonomic arousal across a variety of situations and conditions. Assumption is that low levels f arousal predispose a person to crime because this produces fearlessness and encourages antisocial stimulation.
Amygdala
brain structure that has a major role in regulating emotional responses, fear, and memory
Temperament
defined as a “natural” mood disposition determined largely by genetics and biological influences.
“styles” of children - by Thomas and Chess
- easy child
- difficult child
- slow-to-warm child
Easy child
Characterized by high rhythmicity, positive moods, high approachability, high adaptability, and low intensity or mood expression
Difficult child
characterized by irregular biological function, initial aversion, slow adaptability to environmental changes, high intensity of emotional expression, and generally a negative mood
Slow-to-warm child
Characterized by high activity, withdrawal from new stimuli and people, low adaptability, negative mood, and low intensity.
Features of temperament
1) constitutional or biological basis
2) appear in infancy and continue throughout life
3) influenced by the environment
Neurotoxins
lead
cadmium
manganese
mercury
Plasticity
A characteristic of the brain that describes how it’s structure and function are both affected by experiences.
Neurotransmitters
chemicals, manufactured in the brain, that are involved in biochemical activity and transmission of messages in the nervous system.
Serotonin
A neurotransmitter that exists in large amounts in the frontal lobe, which is involved in planning and self regulation, and has been connected with aggression and violence, although these findings are not empirically proven
Executive function
refers to the higher levels of cognitive processes that organize and plan behavior, including logic and abstract reasoning. Also prioritizes step necessary for solving problems and is closely involved in self-control and self-regulation.
