4. The Biological Approach Flashcards
What is the biological approach
- The biological approach combines psychology & biology to provide physiological explanations for human behaviour.
- Biological psychology tries to explain how we think, feel & behave in terms of physical factors within the body
What is physiology
The study of the body & its parts and how they function
5 points
Basic assumptions of the biological approach
- Everything psychological is at first biological - investigates how biological structures & processes within the body impacts behaviour
- Much of human behaviour has a physiological cause which may be genetically/environmentally altered
- Psychologists should study the brain, nervous system & other biological systems, eg. hormones, neurochemicals.
- The mind lives in the brain (in contrast to the cognitive approach sees mental processes of the mind as being separate from the physical brain)
What are neurochemicals
Relating to chemicals in the brain that regulate psychological/physiological functioning
What is the Genetic basis of behaviour
Psychologists are interested in trying to determine & provide evidence for the extent to which behaviours, or a characteristic sa intelligence, are the product of inheritance (genes), or environmental influences
4 methods
Methods of investigating the Genetic basis of behaviour
There are diff methods for investigating the extent to which psychological characteristics are affected by inheritance from parents & evolution genetic basis of behaviour:
- Twin studies
- Family studies
- Adoption studies
- Selective breeding
Twin studies
Psychologists are interested in studying twins in order to investigate the Genetic basis of behaviour
Twin studies: What is a zygote
A fertilised egg
Twin studies: What are the 2 types of zygotes
- Monozygotic (MZ)
- Dizygotic (DZ)
Twin studies: What are monozygotic twins
ONE zygote - these twins are formed when a fertilised cell splits into two & forms two separate embryos
Twin studies: What are dizygotic twins
TWO zygotes - these twins are formed when two separate eggs both become fertilised by different sperm cells
see showbie for dia of MZ and DZ twins
What is concordance rates
This refers to the extent to which a pair of twins share similar traits or characteristics.
eg. there should be 100% concordance rates between MZ twins if a particular characteristic is a genetic one. DZ twins will show lower concordance.
quote + 2 points
Family studies
Francis Galton, 1869 claimed, “…all natural abilities are inherited”
- This was a simplistic viewpoint - Galton later agreed that any resemblance between family relatives could be a result of both genes & shared env
- However, w alcoholism for eg, there is a suggestion of a biological predisposition to the addiction
Adoption studies
These studies involve comparing a trait or characteristic between adopted children & their biological or adoptive parents
3 points
Selective breeding
- This method involves artificially selecting male & female animals for a particular trait.
- These animals are then put tg in order to breed & produce offspring
- Selective breeding has been used to demonstrate how a no. of behavioural characteristics may have a genetic basis/ eh. ‘maze bright’ rats
3 points
Evidence & research of Genetic basis of behaviour
- There is evidence from twin, family & adoption studies to suggest that certain behaviours, eg intelligence, are genetically determined
- Research has shown that the environment can play more of a role in determining behaviour than genetics
- Selective breeding studies have demonstrate how a no. of behavioural characteristics, eg aggression, can have a genetic basis
What are the basic units of heredity
The basic units of heredity are called genes
linekd to genetic variability
How do genes function
Genes function in pairs & the recombination of genes from parents to offspring provides the basis for genetic variability
linked to genotype & phenotype
How do genes function
- Genes only determine the potential for characteristics (genotype)
- The observable characteristics of an individual (phenotype) depend on the interaction of genetic & environmental factors
What is a Genotype
- The actual set of genes an individual has, or is made up of, is a genotype.
- The genetic material is made up of DNA, for sexually reproducing organisms, which are given by the sperm & egg of the parents
What is a Phenotype
- An individuals anatomical features or observed traits, sa behavioural & physical characteristics (shape, metabolic activities, size, colour, etc) fall under an individuals phenotype
- These behavioural characteristics & physical attributes are what determines an individual’s ability to reproduce & survive in the environment
Difference between Genotype & Phenotype
- The genotype is the genetic programming that provides the phenotype
- To a large extent, an individual’s phenotype is determined by its genotype
How does the genotype provide the phenotype
Genotype + Environment = Phenotype
Examples where phenotype is influenced by the environment
Hair colour
- An individual’s genes determines whether or not they have hair on their head, but how long this hair remains depends on environmental factors, sa excess sunlight, chemicals used, poor diet
- This shows that phenotype is influenced by the env
A gene can be…
…recessive or dominant
What is a recessive gene
A recessive gene only shows if the individual has two copies of the recessive gene.
Eg, the gene for blue eyes is recessive, you need 2 copies of the gene to have blue eyes
What is a dominant gene
A dominating gene always shows, even if the individual only has one copy of the gene.
Eg, the gene for brown eyes is dominant, you only need one copy of the gene to have brown eyes (2 copies will still give you brown eyes)
What are alleles
Genes have different forms called alleles
What are Heterozygous genes
The genotype consists of two different genes
for eg, Bb
What are Homozygous genes
The genotype consists of two genes that are the same
for eg, BB
A good eg of the interaction between genotype & environment
Identical twins
- They have the same genetic makeup & they look alike, but they posses different phenotypes
- Identical twins have differences that allow those who are close to them to tell them apart. Also, their fingerprints are different
- Twins are genetically the same - any differences you may see between them (eg in personality, tastes &. particular aptitudes) are due to differences in their experience or environment
What is evolution
The changes in inherited characteristics in a biological population over successive generations
Who founded the evolutionary theory
Charles Darwin
2 main concepts Charles Darwin emphasised in the evolutionary theory
- Natural selection
- Sexual selection
Evolutionary theory: Natural selection
Animals with particular traits that provide them w an advantage are more likely to survive & reproduce thereby passing on their ‘adaptive traits’ to their offspring
3 principles of Natural selection
The advantageous behaviours need to adapt to the env that the animal is living in which is dependent on 3 principles:
the principle of diversity: the variety within a species
the principle of interaction: which is how this variety of species adapt & fit in w the env. eg. animals that breathe air wouldn’t be able to permanently live underwater
the principle of differential amplification: those who adapt to their env will reproduce & those that do not will die out
What is Sexual selection
- Males have an abundance of sperm & can reproduce w as many females as they want
- Females however, are limited by the amount of eggs produced & the fact that they have to carry the baby for 9months & then raise them until the age of 18
- Females therefore will be more particular about who fathers their children due to the investment they have to make
Research methods of the biological approach
- The biological approach draws on concepts from the hard sciences & research tends to be highly scientific in nature
- The most common methods include laboratory experiments & observations
- Objective brain recording & scanning techniques are also used
The 5 different types of Brain scans
- PET scans
- CAT scans
- MRI
- fMRI
- SQUID magnetometry
What is a PET scan
(Positron emission tomography) - shows which parts of the brain are active during different tasks. As a result, we can link certain areas of brain w particular functions
What is a CAT scan
Detects damaged parts of the brain, tumours & blood clots
Brain structure is shown, NOT function
What is an MRI
Detects small tumours & provide detailed info about structure
What is an fMRI
Structural & functional info
What is SQUID magnetometry
Produces accurate images of brain activity by measuring the magnetic fields generated when neurones are activated
Outside sources of magnetism can affect results
5 points
STRENGTHS of the biological approach
- Is a scientific approach - highly scientific methods so data is reliable
- Scientific approach lends credence to study of psychology - establishes psychology as a respectable science
- Impact of biology on behaviour can lead to treatment & intervention to those suffering (eg. anti-depressants)
- Measurements can be objective as it can be performed by machines which have no vested interest in the outcome. Use of complex machinery allows accurate & precise measurement
3 different approaches
LIMITATIONS of the biological approach
- Is a deterministic approach as believes that we are determined by our physiological, genetic or evolutionary make-up, thus stating there is no free will
- Is reductionist - states that all behaviour can be explained through biological processes & we are therefore not unique as individuals. Also dehumanising to present humans as ‘biological machines’
- Ignores the role of the environment - should be used in combination which is known as the biopsychosocial approach
6 points
LIMITATIONS of the biological approach
- Research may focus on rare conditions that have little impact on the everyday lives of most ppl
- Complex machinery operated by humans & therefore measurements could be subject to human error
- Small or restricted samples - findings are difficult to generalise
- Lacks ecological validity - laboratory experiment
- Cannot separate nature from nurture
What did Gottesman do in 1991
A meta-analysis of twin studies
Method of Gottesman
Carried out a meta-analysis of approximately 40 twin studies
Results of Gottesman’s meta-analysis of twin studies
Found that having an identical twin w schizophrenia gave you a 48% chance of developing the condition. This reduced to 17% in non-identical twins
Conclusion of Gottesman’s meta-analysis of twin studies
Schizophrenia has a strong genetic basis
Evaluation of Gottesman’s meta-analysis of twin studies
- Was carried out on field studies - high ecological validity
- Identical twins share 100% of their genes, it might be expected that both twins would always suffer from the same condition. The fact that both twins had developed schizophrenia in only abt half of cases means another factor must be involved.
- Identical twins tend to be treated more similarly than non-identical twins, & so the family env may play a large role
What did Heston do in 1966
An adoption study of schizophrenia
Method of Heston’s study
- 47 adopted children whose biological mothers had schizophrenia were studied. The control group consisted of 50 adopted children whose biological mothers didn’t have schizophrenia.
- The children were followed up as adults and were interviewed & given intelligence/personality tests
Results of Heston’s study
- Of the experimental group, 5 of the 47 became schizophrenic, compared to 0 in the control group
- Another 4 of the experimental group were classified as borderline schizophrenic
Conclusion of Heston’s study
The study supports the view that schizophrenia has a genetic basis
Evaluation of Heston’s study
- Interview data can be unreliable/affected by social desirability bias
- HOWEVER, interviews are a good way of getting data in naturalistic way
- Adopted children whose mothers didn’t suffer from any conditions might have not shown any symptoms of schizophrenia yet
What did Maguire et al do in 2000
A study of taxi driver’s brains - ev from MRI scans to show changes in brain structure
Method of Maguire et al
- In a natural exp, MRI scans from 16 licensed male London taxi drivers were compared w a control group who had never driven taxis.
- All participants were in good neurological & psychiatric health, w an avg age of 44, all drivers had been working for at least 18months
Results of Maguire et al
- The avg size of the right posterior hippocampus was SIGNIFICANTLY LARGER in taxi driver group compared to control group.
- Increased size was relative to length of time driver had been working (longer, the larger)
Conclusion of Maguire et al
The hippocampus is responsible for storing a spatial representation of the env - it seems that the specific navigational demands on taxi drivers have resulted in physical change
Evaluation of Maguire et al (medical side)
Results could be used to help those w brain injuries as it shows that size of structures within brain can be influenced through cognitive activity –> rehabilitation could be tailored to specific needs of individuals & their injuries
Evaluation of Maguire et al
- Study had a good level of control - replicable, increasing reliability
- HOWEVER, sample size too small & results can only be generalised to male taxi drivers in London
What is neurochemistry
All abt the nervous system & neurotransmitters
Biological approach on neurochemistry
BA looks at the role neurochemistry may play in explaining behaviour
- Too much/little of a particular neurotransmitter may produce psychological disorders (eg. increased dopamine levels linked to schizophrenia)
