Psychology biological level of analysis revision

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Test Revision Psychology

General Learning Outcomes

Outline principals that define the biological level of analysis

1. Many behaviours have physiological origins (e.g. brain processes, neurotransmitters, hormones, and genes), so humans should be studied as biological systems

2. The relationship between physiological factors and environmental stimuli is bi-directional. This means that biology and the environment influence each other.

3. Cognitions, emotions and behaviours are products of the anatomy and physiology of our nervous and endocrine systems.

4. Behaviour can be innate and inherited because it is genetically based. Evolution therefore, plays a key role in behaviour.

5. Animal research provides insight into human behaviour. It provides a base to consider human behaviour and an avenue to investigate when it is unethical to experiment on humans.

6. There are biological correlates of behaviour, that is links between specific biological factors and specific behaviours. E.g. testosterone and aggression.

7. Biological research is often reductionist. Reductionism refers to a micro-level research approach where complex human behaviour is reduced to its smallest parts. For example, reducing the explanation of aggression to testosterone levels.

Strength: provides detailed knowledge of physiological components.

Limitation: oversimplified as it ignores other explanations of behaviour, e.g. in the aggression example, there are relevant social and cognitive explanations that if considered would provide a holistic (more complete) picture.

Explain how principals that define the biological level of analysis may be demonstrated in research.

Two principles that are demonstrated in research are: that many behaviours have physiological origins so humans should be studied as biological systems and that animal research can provide insight into human behaviour.

Serotonin has been linked to hallucination as investigated in 1999, by Kasamatsu and Hirai to investigate the effects of sensory deprivation on the brain. This experiment studied a group of Buddhist monks over a 72 hour pilgrimage to a holy mountain in Japan. The researchers took blood samples before the monks ascended the mountain. The monks were exposed to the harsh autumn weather, did not speak or consume water or food. After approximately 48 hours, the monks began to hallucinate claiming that they saw ancient ancestors or they felt their presence. Immediately, blood tests were taken and stated that serotonin levels increased. They concluded that sensory deprivation triggered the release of serotonin. Increased serotonin activates the hypothalamus and frontal cortex which results in hallucination. Thus behaviours have physiological origins so humans should be studied as biological systems.

A key study was conducted in 1991 by Martinez and Kesner to determine the role of acetylcholine in memory using rats. The lab rats were trained to go through a maze, where at the end they received food. The first group was injected with scopolamine, the second group was injected with physostigmine and the final group was the control group. Results from the experiment showed that rats from the 1st group were slower at the maze and made more errors than groups 2 and 3. On the other hand, group 2 rats were quicker at the maze and made fewer mistakes than groups 1 and 3. They concluded that acetylcholine played a role in creating a memory of the maze. A biological psychology principle states that animal research provides insight to human behaviour; animal research is relevant to human behaviour as supported by Darwin’s theory of evolution.

Discuss how and why particular research methods are used at the biological level of analysis

Experiments on humans and animals

  • Animals are experimented on when it would be harmful to humans and the results have great benefits for humans.
  • Experiments can use a range of techniques:
  • Lesions: study the effect of a lesion, i.e. injury
  • Stimulation: insertion of tiny electrodes into the brain to see what effects a mild electric current has on specific brain regions.
  • Brain imaging technologies
  • Chemical manipulation: using drugs to influence brain neurotransmitter levels
  • It shows cause and effect relationships but have poor ecological validity

Case studies (e.g. Brain damage, H.M.)

  • Follow the case of one person with a particular kind of damage that researchers cannot create in the lab on humans.
  • In-depth study of specific phenomenon.
  • Can compare to similar cases and prompt future research.
  • May be only way some phenomenon can be studied.
  • However, poor external validity (can’t generalise to larger population)
  • Difficult to replicate

Postmortem studies: allow direct observation of brain tissue after a person has died

  • Often case studies
  • Can be longitudinal, i.e. document case while alive, and then dissect brain after death. E.g. Broca’s patient Tan.
  • Specific brain locations and functions can be identified for further study
  • But cause and effect can’t be easily determined.

Brain imaging technologies:

  • Includes EEG, PET, CAT, MRI and fMRI.
  • Provide empirical evidence of brain functioning when specific tasks are performed.
  • It can be used in experiments.
  • Imaging will allow us to detect differences between images but…
  • May not help explain why differences exist
  • Expensive

Correlational studies

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  • Analyse data in biological studies to test for relationships between variables.
  • There are two specific methods in genetic research that use correlations: Twin studies and adoption studies
  • Can be used when ethics or the type of research question prohibits an experiment.
  • But correlation is not causation

Physiology and behaviour

Explain one study related to lateralization of function in the brain

One quasi experiment of lateralisation of the brain functions was lead by Roger Sperry. He performed a test on patients with severe epilepsy. He chose patients who had their corpus callosum cut in order to cure their epilepsy. ...

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