1. The Biological Approach
Specification details:
Basic assumptions of the biological approach including: the influence of genes, biological structures and neurochemistry on behaviour, genotype and phenotype, genetic basis of behaviour, evolution and behaviour.
Pages of course text book

2. What is the biological approach?
The biological approach combines psychology and biology to provide *physiological explanations for human behaviour.
Biological psychology tries to explain how we think, feel and behave in terms of physical factors within the body.
*Physiology: the study of the body and its parts and how they function

3. Basic assumptions Everything psychological is at first biological
The approach investigates how biological structures and processes within the body impacts on behaviour.
Much of human behaviour has a physiological cause which may be genetically or environmentally altered.
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)

4. What have we already learned?
What have we still got left to do?
Evolution and behaviour.
Genotype and phenotype
Genetic basis of behaviour

5. 1. Evolution and behaviour
Evolution: the changes in inherited characteristics in a biological population over successive generations
Charles Darwin emphasised two main concepts in evolutionary theory:
natural selection
sexual selection

6. Natural selection
Animals with particular traits that provide them with an advantage are more likely to survive and reproduce thereby passing on their ‘adaptive traits’ to their offspring.
These behaviours need to adapt to the environment that the animal is living in which is dependent on three principles:
the principle of diversity - the variety within a species
the principle of interaction - which is how this variety of species adapt and fit in with the environment e.g. animals that breathe air wouldn’t be able to permanently live under water
the principle of differential amplification - those who adapt to their environment will reproduce and those that do not will die out.

7. Sexual selection
Males have an abundance of sperm and can reproduce with as many females as they want.
Females however, are limited by the amount of eggs she produces and the fact that she has to carry the baby for 9 months and then raise it till the age of 18.
Females therefore will be more particular about who fathers their children due to the investment they have to make.

8. 2. Genetic basis of behaviour
Psychologists are interested in trying to determine and provide evidence for the extent to which behaviours, or a characteristic such as intelligence, are the product of inheritance (genes), or environmental influences

9. Methods of investigating the genetic basis of behaviour
There are different methods for investigating the extent to which psychological characteristics are affected by inheritance from parents and evolution genetic basis of behaviour:
twin studies
family studies
adoption studies
selective breeding

10. Twin studies
Psychologists are interested in studying twins in order to investigate the genetic basis of behaviour
Zygote
A fertilised egg
Monozygotic (MZ)
One zygote – these twins are formed when a fertilised cell splits into two and forms two separate embryos
Dizygotic (DZ)
Two zygotes – these twins are formed when two separate eggs both become fertilised by different sperm cells

11. Family studies
Francis Galton ‘…all natural abilities are inherited’
This is a simplistic viewpoint – Galton later had to agree that any resemblance between family relatives could be a result of both genes and shared environment
However, with alcoholism for example, there is a suggestion of a biological predisposition to the addiction

12. Adoption studies
These studies involve comparing a trait or characteristic between adopted children and their biological or adoptive parents.

13. Selective breeding
This method involves artificially selecting male and female animals for a particular trait.
These animals are then put together in order to breed and produce offspring.
Selective breeding has been used to demonstrate how a number of behavioural characteristics may have a genetic basis. e.g. ‘maze bright’ rats

14. 3.Genotype and phenotype
The basic units of heredity are called genes
Genes function in pairs and the recombination of genes from parents to offspring provides the basis for genetic variability
Genes only determine the potential for characteristics (genotype)
The observable characteristics of an individual (phenotype) depend on the interaction of genetic and environmental factors.

15. The Difference between Genotypes and Phenotypes
The genotype is the genetic programming that provides the phenotype
To a large extent, an individual's phenotype is determined by its genotype.
However, genes are only part of the equation
Genotype + environment = phenotype

16. Evaluation of biological approach
Strength Weakness

17. Strengths of biological approach
It is a scientific approach. This suggests that we can find cause and effect relationships of both physiology and behaviour.
Scientific approach lends credence to study of psychology – establishes psychology as a respectable science
Impact of biology on behaviour can lead to treatment and intervention to those suffering
Understanding how an abnormal brain works can shed light on normal brain functioning
Measurements can be objective as it can be performed by machines which have no vested interest in the outcome e.g. PET scans, EEGs etc. Use of complex machinery allows accurate and precise measurements

18. Limitations of biological approach
It is a deterministic approach as it believes that we are determined by our physiological, genetic or evolutionary make-up. Thus stating that there is no free will.
This approach is reductionist by stating that all human behaviour can be explained through biological processes and we are therefore not unique as individuals. It is also dehumanising to present humans as ‘biological machines’
Biological approach ignores the role of the environment etc. it should be used in combination which is known as the biosocial approach.
Research may focus on rare conditions that have little impact on the everyday lives of most people
Complex machinery operated by humans and therefore measurements could be subject to human error
Correlations frequently employed – cannot determine cause and effect
Small or restricted samples make findings difficult to generalise
Laboratory experiments lack ecological validity

19. Can you?
Explain what is meant by genotype and phenotype (2 marks each)
Outline the influence of genes on behaviour (3 marks)
Using an example, explain how neurochemistry can influence behaviour (3 marks)
Outline the relationship between evolution and behaviour (4 marks)
Outline two weaknesses of the biological approach in psychology (4 marks)
Answer the ‘Check it’ questions on page 113 GHG