The Biological Approach Flashcards
what is the biological approach
assumes all psychological behaviours/functions have a biological root at their core
examples of biological structures
genetics
neurotransmitters
hormones
brain structures
what is the genetic basis of behaviour
investigates the extent to which behaviour is inherited
how many pairs of chromosomes is a human born with
23
What are twin studies used for, and how do they measure genetic influence on traits?
Investigate genetic basis for traits (e.g., schizophrenia, IQ, criminality).
Compare Monozygotic (MZ) and Dizygotic (DZ) twins.
Focus on concordance rates (agreement rates).
High concordance rate = strong genetic connection to trait/behavior
what if characteristic is genetic
100% of MZ twins share that characteristics
what is a genotype
persons particular set of genes that make up their DNA
traits of genotypes
Unique to each individual (except MZ twins, who share 100% DNA).
Determines physical traits (e.g., eye/hair color).
Fixed at conception; only changes with rare mutations.
Environment influences how genotype is expressed as a phenotype.
what is a phenotype
Observable traits resulting from genotype + environmental influences eg height, eye color, hair texture, blood type.
How do environmental factors shape the expression of genotype in phenotype?
Phenotype influenced by environment: Nutrition, pollutants, social factors.
Examples:
Genotype sets height potential, but diet determines if max height is achieved.
Genotype may predispose to behaviors (e.g., criminality), but environment determines expression.
Secure environments: Reduce likelihood of negative traits (e.g., crime).
Adverse environments: Increase likelihood of negative traits.
Even MZ twins: Show different phenotypes due to unique life experiences
Evaluation of assumptions & the influence of genes: real world application
Drug therapies: Success of SSRIs for treating depression and OCD.
Family history: Reliable predictor of disease risk because of understanding of (genotype + environmental factors)
Evaluation of assumptions & the influence of genes: twin studies use large samples
researcher studied heritability of IQ with over 1,500 twin pairs and 350 adopted/biological siblings.
Findings: MZ twins reared together had a correlation of +0.9 (significant).
Strengths: Large sample size and quantitative data provide good reliability.
Evaluation of assumptions & the influence of genes: biological determinism
BA is the belief that human behavior is solely determined by genetics.
Ignores environmental factors and cognitive processing.
Reduces external validity by oversimplifying human behavior
Evaluation of assumptions & the influence of genes: mixed up MZ and DZ twins
Physical resemblance could mislabel twins as MZ instead of DZ
Damage validity
what structures do the BA play a key role in human behaviour
nervous system, the endocrine system and the brain
what does the nervous system consist of
CNS
PNS ( Peripheral Nervous System)
functions of cns
Comprises the brain and spinal cord; it receives, sends, and responds to sensory information.
functions of PNS
Relays information between the body and the brain, including involuntary responses (e.g., breathing, heartbeat), sensory information, and control of voluntary movement.
what is the endocrine system
chemical messaging system operating throughout the body.
secrete hormones into bloodstreams from different glands
what is the brain
made up of different regions localised for different functions
eg temporal, frontal lobe and cerebellum.
what is temporal lobe
controls auditory perception
and controls speech comprehenison
what is the frontal lobe
voluntary movement and expressive language
what is the cerebellum
receives info from spinal cord
regulates balance and motor movements
the evolutionary approach when explaining behaviour
based on Darwin’s theory, examining how human traits evolved through natural selection
examples of evolutionary apporach
aggression
memory
language
mate selection
example of aggression evolution
Useful for fighting off predators and enemies.
example of evolutionary memory
Useful for recalling the location of food sources
example of evolutionary language
useful for communicating with tribe members
example of mate selection
usefulness to select a mate who will bear healthy offspring
what are adaptive behaviours
Behaviours that increase chances of survival and reproductive success. passed through generations
biological structures & neurochemistry AO3: objective methods
Zak et al. (2009): Linked testosterone levels in blood samples to reduced prosocial behaviour.
Maguire et al. (2000): Used MRI scans to study the hippocampus’s role in spatial navigation.
results can be checked for consistency meaning good reliability
biological structures & neurochemistry AO3: compelling evidence supporting evolution and behaviour
Curtis found ppl showed more disgust to disease-salient images than neutral shows that disgust is evolutionary to prevent us from ingesting toxic materials ; lends validity that humans are biologically programmed for survival
biological structures & neurochemistry AO3: overly reductionist
testosterone levels alone cannot fully explain a lack of prosocial behavior; personality and upbringing also play a role.
spatial naviagtion Not solely dependent on the hippocampus; cognitive abilities (e.g., memory) and social factors (e.g., familiarity with London streets from childhood) contribute as well.
biological structures & neurochemistry AO3: non advantageous behaviours still remain
behaviors like aggression are no longer advantageous
don’t need to fight for food and excessive aggression can lead to police involvement and social isolation
these explanations can not fully account for behaviours in today’s societal and environmental context
