Biological

• AO1 - 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
• AO1 - 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.

  Genes affect behaviour and influence individual psychological differences between people.  Evolutionary psychology considers genetic influences in common behaviours
• AO1 - Assumptions

  • Psychologists should study the brain, nervous system and other biological systems, e.g. hormones, chemicals acting on the brain.
  • 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).
• AO1 - 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
• AO1 - Methods 

  There are different methods for investigating the extent 

  to which psychological characteristics are affected by 

  inheritance from parents and evolution genetic basis of 

  behaviour:

  Can you guess them?

  • Twin studies
  • Family studies
  • Adoption studies
• AO1 - Twin studies

  Psychologists are interested in studying twins in order to investigate the genetic basis of behaviour

  Twin studies often focus on the presence of a behaviour or trait between monozygotic (MZ) twins and/or dizygotic (DZ) twins. 

  This is known as the concordance rate

  Concordance Rates = The probability (as a percentage) that if one twin has a characteristic the other twin will have the characteristic.
• AO1 - Twin studies

  MZ twins are also known as identical twins 100% of their DNA with each other as they come from the same egg

  • they share

  DZ twins are no more related than any other siblings. They come from 2 separate eggs and only share 50% of their DNA with one another
• AO1 - Family studies

  1869 - Francis Galton ‘…all natural abilities are inherited’

  Whilst 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
• AO1 - Adoption studies

  These studies involve comparing a trait or characteristic between adopted children and their biological or adoptive parents.
• AO1 - Genetic basis of behaviour

  There is evidence from twin, family and adoption studies to suggest that certain behaviours, for example, intelligence, are genetically determined

  Research has shown that the environment can play more of a role in determining behaviour than genetics
• AO1 - Genotypes and phenotypes

  • 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.
• AO1 - 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 and egg of the parents.
• AO1 - Phenotype

  An individual's anatomical features or observed traits, such as behavioural and physical characteristics (shape, metabolic activities, size, and colour, etc.), fall under an individual's phenotype. 

  These behavioural characteristics and physical 

  attributes are what determines an individual's 

  ability to reproduce and survive in the 

  environment.
• AO1 - 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
• AO2 - Example

  Hair is a good example. 

  An individual's genes determines 

  whether or not they have hair on their head, but how long this hair remains depends on environmental factors, such as excess sunlight, chemicals used on the head, or poor diet. 

  This shows that phenotype is influenced by the environment
• AO2 - Differences in twins

  • Identical twins are another good example of the 

  interaction between inheritance and environment. 

  • They have the same genetic makeup and they look alike, but they can possess 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 are due to differences in their experience or environment (their phenotypes)

  • any differences you may see between them – for example in personality, tastes and particular aptitudes –
• AO1 - Evolution and behaviour

  Charles Darwin emphasised two main concepts in evolutionary theory:

  • natural selection
  • sexual 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.
• AO1 - Evolution and behaviour

  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.
• AO1 - Research methods

  The biological approach draws on concepts from the hard sciences and research tends to be highly scientific in nature

  The most common methods include laboratory experiments and observations

  Objective brain recording and scanning techniques are also used