Evolution and natural selection Flashcards
What are the 3 steps to Darwin’s Theory of Evolution by Natural Selection?
- Genetic variation - naturally occurs in a population due to new alleles formed by mutations
- Selection pressure put on population - created by a change in the environment
- Survival of the fittest - organisms with favourable alleles survive, reproduce and form offspring which inherit the desired characteristics
How did aggression come about through evolution? (2 points)
Chimpanzees engaging in organised violence suggests that humans and chimps both evolved to have such behaviour before their species diverged 6 million years ago
An evolved strategy to assert dominance - survival advantage to males because females are more attracted to them
How can the development of aggression be explained using Darwin’s Theory of Evolution? (3 points)
Genetic variation - differences in aggression
Selection pressures - competition for partners
+ Causes aggressive behaviours to occur as a solution to the adaptive problem
Survival of the fittest:
+ Those better adapted to defend territory or maintain mates survive and reproduce
+ Causes genes coding for aggression to be inherited by offspring
What are the supporting and refuting arguments for evolution and natural selection causing aggression?
Supporting:
S - Thornhill and Palmer
C - Mertins et al (2011) and Chester et al (2013)
A - Bradley Waldroup
Refuting:
O - Freud and Lorenz (1966)
D - SLT
What is the strength of evolution as an explanation of human aggression? (4 points)
Human aggression being a survival advantage that makes people stronger and more attractive to females is supported by Thornhill & Palmer (2000)
They hypothesised humans have evolved to rape to obtain otherwise inaccessible partners
They argued that the behaviour of rape evolved over millennia of human history, along with courtship, sexual attraction and other behaviours related to the production of offspring
This explanation is linked to the evolution of humans from common ancestors like chimps who also display similar acts of aggression
How credible is evolution as an explanation of aggression? (2 points)
The role of genes in human evolution is empirically supported by research studies like Mertins et al (2011) and Chester et al (2013)
Such empirical research studies are falsifiable and objectively measure a person’s genotype - increased credibility
What is the MAO-A/Warrior gene? (4 points)
Mono Amine Oxidase A (MAOA) - gene that codes for the MAO-A protein
MAO-A protein normally breaks down excess neurotransmitters like serotonin and dopamine
A mutation in the gene MAO-A causes the enzyme to malfunction, causing excess neurotransmitters to remain in the synapse
Results in continued/sustained synaptic neurotransmission, manifesting as aggressive human behaviour like violent outbursts and rage
How does Mertins et al (2011) support the credibility of evolution as an explanation of aggression? (4 points)
They studied the correlation between the MAOA gene and behaviour in a public goods game
The game involved contributing and sharing a sizeable share of participants’ endowment of 20 points
The findings showed in male participants
+ MAOA-H allele were associated with greater pro social behaviour
+ MAOA-L allele contributed less significantly
How does Chester et al. (2015) support the credibility of evolution as an explanation of aggression (3 points)
Found that low functioning MAOA-L genotype (‘warrior gene’) was linked to greater aggression
Presence of MAOA-L allele:
1. Lack of breakdown of neurotransmitters
2. Increased synaptic neurotransmission
3. Greater reactivity to negative experiences
E.g. negative urgency and the tendency to act impulsively
Are there any other explanations for aggression other than evolution? (4 points)
The evolution explanation suggests it could be an epigenetic process
However, the correlation between genotype and human aggression does not imply causation as there could be other biological explanations
Freud and Lorenz (1966) suggest that violence exists within everyone due to a basic instinct to dominate
Aggressive energy builds up until it needs to be released through catharsis
Is there any room for debate on evolution as an explanation of aggression? (3 points)
Aggressive behaviour may be due to the inheritance of an aggressive gene combined with abusive environmental experiences
Can also be considered reductionist - fails to consider the influence of learning behaviour in social environments, unlike Bandura’s (1966) Social Learning Theory
Evolution as an explanation of human aggression remains incomplete as it does not fully account for gender differences
How does Bandura’s Social Learning Theory explain aggression? (2 points)
Aggressive behaviour is learned through the observation and imitation of same-sex role models
Findings showed that boys copied an average of 25.8 aggressive acts from a male role model whilst girls copied 5.5 aggressive acts from a female role model
How can evolution as an explanation for aggression be applied to real life? (4 points)
Can be applied to real life cases of criminal activity such as Bradley Waldroup (2007) - brutally murdered his wife, shooting her 8 times
Waldroup’s defence argued that his high-risk version of MAOA coupled with his experience of child abuse led to a 400% increase in the odds of being convicted of a violent crime as an adult - led him to him being charged with voluntary manslaughter, not murder
Suggests important applications of the evolution explanation when trying to understand the behaviour of violent criminals
However, critics would argue the use of genetic screening for criminals and human populations is a form of social control
