genetic explanations Flashcards
what are genetic factors?
the likelihood of behaving in a particular way is determined by a persons genetic makeup (heredity)
what are monozygotic twins?
identical twins, share 100% DNA
what are dizygotic twins?
non-identical twins, share 50% DNA
why do researchers use twin studies for genetic influences?
compare concordance rates of behaviours between MZ and DZ twins, if behaviour is genetically determined rates should be higher for MZ twins
what did coccaro find in relation to genetics and aggression?
studied aggressive behaviour using adult twin pairs and found that nearly 50% of the variance in direct aggression is down to genetic influences
why do researchers use adoption studies for genetic influences?
help to untangle the effects of the environment and biological factors
when using adoption studies, how would you determine a genetic influence on behaviour?
if a positive correlation is found between aggression in the adopted child and the biological parent/s
what did the danish adoptee study find?
studied 14,000 adoptions
a significant number of adopted boys with criminal convictions had biological parents (particularly fathers) with criminal convictions for violence
how do we see genetic influence in animals?
psychologists have used selective breeding in animals and have found that aggression is a trait that can be transmitted from parent to offspring
what gene is linked to aggression in humans?
MAOA gene
what is the MAOA gene?
responsible for producing the enzyme monoamine oxidase, which breaks down neurotransmitters
how does the MAOA gene affect neurotransmitters?
serotonin: low levels, lack of inhibition of impulsive behaviour
dopamine: high levels, feelings of reward when aggressive behaviour is carried out
noradrenaline: overreaction to perceived threats
what variant of the MAOA gene is linked to aggressive behaviour?
MAOA-L gene
what does the MAOA-L gene cause?
associated with lower levels of monoamine oxidase A enzyme activity
where is the MAOA-L gene most common?
more frequent in populations with a history of warfare (two thirds had this gene variant)
when is the MAOA-L gene most likely to be linked to aggression?
when combined with environmental factors, such as childhood maltreatment or abuse
what research support is there for the role of genetics influencing aggression?
Stuart et al:
conducted a study involving 230 male perpetrators of intimate partner violence.
they found that individuals with the MAOA-L gene variant were more likely to engage in violent behavior compared to those with the high-activity MAOA variant.
moreover, this gene-environment interaction was stronger for men who had experienced childhood abuse.
what does stuarts research mean for genetic influences?
shows that the MAOA gene plays a crucial role in aggressive behavior but also points to the environmental influence which suggests that genetics isnt a complete explanation
how can we see the diathesis stress model in genetic explanations?
Caspi:
illustrates how genetic predispositions interact with environmental stressors
examined a large sample of males and found that those with the MAOA-L gene variant were more likely to engage in antisocial and aggressive behaviors.
however, this was only true for those who had also experienced significant childhood maltreatment. Men with the low-activity MAOA gene but no history of abuse did not exhibit increased aggression
what does the diathesis stress model mean for genetic explanations?
suggests that genetic predispositions alone are not sufficient to cause certain behaviors, such as aggression.
instead, these genetic factors interact with environmental stressors to trigger the manifestation of these behaviors
why are genetic explanations deterministic?
suggest that aggression is caused by variations in our genes such as the MAOA-L gene
why are deterministic explanations a problem?
genetic explanations, such as those suggesting a link between the MAOA-L gene and aggression, imply that individuals may have a genetic predisposition to aggressive behavior.
if aggression is seen as biologically determined by genetic factors, it may be argued that individuals have less control over their actions, potentially affecting their accountability in legal contexts.
what does the deterministic position mean for genetic explanations?
by attributing aggression solely to genetic factors, it risks excusing harmful behavior and undermining the fairness of the legal system, limiting them as an explanation
how are genetic explanations reductionist?
simplify aggression down to biological structures
what is a problem with genetic explanations being reductionist?
research suggests that aggression is influenced by multiple genes, such as the MAOA-L gene, but no single gene is responsible for aggressive behavior.
additionally, niche-picking—where individuals select environments that suit their genetic predispositions—may further complicate the link between genetics and aggression.
for instance, individuals with a genetic predisposition to aggression might gravitate toward environments or situations that encourage aggressive behavior, such as associating with peers who engage in violent activities.
why is being reductionist an issue?
therefore, this means that genetic explanations for aggression are limited in their ability to fully explain the phenomenon.
they fail to account for the intricate ways in which genetic predispositions interact with environmental factors.
the reductionist approach, which isolates genetics as the primary cause of aggression, overlooks the complexity of human behavior, where multiple genetic, environmental, and social factors come into play.
