Approaches - Biological approach

Question 1

Assumptions of the biological approach

Answer 1

• To fully understand human behaviour, we must look at biological structures and processes within the body
• An understanding of the brain structure and brain function can explain thoughts, feelings and behaviour.
• Genes influence behaviour and because the genes we inherit are from distant ancestors, biopsychologists think behaviour has evolutionary explanations

Question 2

Explain the influence of genes on behaviour

Answer 2

• The nucleus of every cell except sex cells contiain 46 chromosomes (23 pairs inherited from parents)
• Chromosomes are our genotype and form the basis for our development
• Chromosomes are made up of a chemical called DNA
• The DNA on each chromosome carries information called genes
• Our genes interact with the environment to influence every aspect of our bodily structure and function

Question 3

Explain what is meant by genotype and phenotype

Answer 3

• Genotype: Individual’s genetic makeup. It occurs at conception and provides the genetic code for how the individual will develop. Each individual has 100,000 genes. The genotype dictates eye and hair colour and each individual except identical twins has their own unique genotype.
• Phenotype: The product of what happens when the genotype interacts with the environment. For example, the genotype dictates the height an individual can reach but environmental factor such as nutrition will affect how likely a person is to achieve their potential height

Question 4

Explain the genetic basis of behaviour

Answer 4

• Behavioural geneticists are interested in the degree to which psychological characteristics: ability, personality and emotional stability are transmitted from parent to offspring
• Some psychological characteristics that are thought to be influenced by genes are: intelligence, psychological disorders and male and female differences

Question 5

Explain the evolutionary theory of behaviour

Answer 5

• Any genetically behaviour that enhances an individual’s survival and reproduction will be passed on in genes to future generations e.g. to be naturally selected
• Natural selection occurs because some genetically inherrited traits give the possessor certain advantages
• Possessor is more likely to survive and reproduce, passing these genes on to future generations.
• Aggression is one behaviour that is thought to be naturally selected - the most aggressive animals stayed alive by defending their territory by ensuring their food source which is neccessary for survival and mating

Question 6

What does concordance rate mean?

Answer 6

The extent to which both twins in a sample share a certain disorder, trait or behaviour.
* Twins are described as concordant for a disease, disorder or trait when both twins have it
* Twins are described as discordant when only one twin has the disease, disorder or trait

Question 7

Explain twin studies

Answer 7

• Twin studies are used to look at the concordance rates between identical and non identical twins to help understand the genetic basis of certain behaviours.
• Identical twins (monozygotic) are 100% genetically similar and non identical twins are 50% similar (dizygotic)
• The likelihood of identical twins having a disorder compared to the likelihood that non identical twins having a disorder gives an indication of how much the behaviour may be genetic

Question 8

The Bouchard and McGue twin study - 1981

Answer 8

• They performed an intelligence study and compiled results of 111 studies and found following concordance rates:
  MZ twins raised together: 87%
  MZ twins raised apart: 72%
  DZ twins raised together: 60%
  Siblings raised together: 47%

Question 9

Explain the evaluations of twin studies

Answer 9

Positive- Perfect participants
Identical twins share 100% of genes and non identicals share 50%. In the twin study of 1981, it’s clear that IQ has a genetic basis due to their being a 27% difference in concordance rates of identical and nonidentical twins raised together. This is a strength because they’re an ideal sample and provide useful data when trying to support the biological approach.
Negative - Same environment
Identical twins are exposed to very similar environmental conditions when they’re raised. Parents often dress them the same and they aren’t treated as individuals. 87% of identical twins in the twin study of 1981 would have shared very similar experiences. This is a weakness because it means findings could just be interpreted as supporting nurture rather than nature.

Question 10

Explain the PET scan study

Answer 10

• Raine in 1997
• He used PET scans to compare brain activity in murderers to normal people’s brain activity
• He found differences in areas of the brain such as the prefrontal cortex which is a region associated with aggressive behaviour

Question 11

Explain the evaluations of scientific equiptment and scanning techniques

Answer 11

Positive - Objective data
Methods favoured by biopsychologists are precise, objective and highly scientific. in raine’s study, psychologists were reading a PET scan. This means the data was objective and not open to interpretation. This is a strength because the results will add to the validity of the biological approach and due to the methods being so scientific, it increases the inter rater reliability because all psychologist will interpret the objective results the same.
Negative - Several weaknesses
PET scans have weaknesses as they are extremely costly and the patient has to be injected with radioactive substances.They are also less accurate than MRI scans. In Raine’s study, it would’ve been an invasive method for the participants because before their brain was studied, they were injected with a radioactive substance. This is a weakness because it could cause more stress to an already stressed patient