Biological Approach Flashcards
What are the approach’s main assumptions?
The biological approach attempts to explain behaviour as the direct product of interactions within the body.
Biological psychology is the study of the biology of behaviour; it focuses on the nervous system, hormones and genetics. Essentially, this approach examines the relationship between mind and body, neural mechanisms, and the influence of heredity on behaviour.
The biological approach believes human behaviour to be a consequence of our genetics and physiology. It is the only approach in psychology that examines thoughts, feelings, and behaviours from a biological and thus physical point of view. Therefore, all that is psychological is first physiological. All thoughts, feelings and behaviours ultimately have a biological cause.
Key assumptions of the biological approach
- There is a direct correlation between brain activity and cognition (thoughts) and brain physiology can affect behaviour - all behaviour is ultimately produced by the operation of systems that connect specific localised regions of the brain. The cortex (outer layer of the brain) is largely responsible for thought, language, vision and movement, whereas fine movement and skill execution are dominated by the action of the cerebellum.
- Biochemical imbalances can affect behaviour - these chemicals are agents of communications between neurons at the synapse, stimulating or inhibiting the action of the receptive neuron. Examples include melatonin (influences sleep/wake cycles) and serotonin (sleep, arousal, mood).
- Behaviour can be inherited (as it is determined by genetic information) - much of our behaviour is determined to some extent by our primate inheritance and the environment that shaped our unique adaptation for survival. Humans are, as a result, intensely social animals, who developed cooperative and planning skills in hostile food-gathering environments.
1) Genetics - The genetic basis of behaviour
Behaviour geneticists study whether behavioural characteristics, such as intelligence, personality, mental disorder, etc, are inherited in the same way as physical characteristics such as height and eye colour. Twin studies are used to determine the likelihood that certain traits have a genetic basis by comparing the concordance rates between pairs of twins; that is, the extent to which both twins share the same characteristic. If identical (monozygotic) twins are found to have higher concordance rates than non-identical (dizygotic twins) - for musical ability, schizophrenia, love of romantic films, etc - this would suggest a genetic basis. This is because MZ twins share 100% of each other’s genes, whilst DZ twins share about 50% (the same as any siblings).
Recent research has found that MZ twins have an increased concordance rate of developing schizophrenia, compared to DZ twins. Other psychological conditions are also influenced by genes. For example, McGuffin et al. (1996) found that if one identical twin has depression, there is a 46% chance that the other twin will also have depression. This suggests that there is a genetic component to illnesses like schizophrenia and depression. These relationships are important for understanding the genetic component of psychological illnesses and demonstrate the impact of genes on certain human conditions.
1) Genetics - Genotype and Phenotype (1)
A person’s genotype is their actual genetic make-up, whereas phenotype is the way that genes are expressed through physical, behavioural and psychological characteristics. The expression of a genotype is inevitably influenced by environmental factors. For instance, identical adult twins usually look slightly different because one has exercised more or one has dyed their hair and so on. So, despite having the same genes, the way identical twins’ genes are expressed (the phenotype) is different.
A practical example of the difference between genotype and phenotype is PKU which is a genetic disorder that affects the ability to break down a substance contained in normal foods. If the individual follows a strict diet avoiding this substance, his phenotype will be normal for intelligence and behaviour; however, if an individual eats a diet containing the substance, then it will accumulate in the brain, which will lead to a different phenotype: severe learning difficulties and behavioural problems. This shows that the presence of particular genes might lead to different outcomes depending on the social environment. This shows that characteristics depend upon an interaction between the genes and the environment.
2) Evolution and behaviour
The evolution of animals and plants is a fact. In the 19th century, Charles Darwin proposed a theory to explain this fact - the theory of natural selection. The main principle of this theory is that any genetically determined behaviour that enhances an individual’s survival (and reproduction) will continue in future generations, i.e. be naturally selected. This happens in a similar way to a farmer deciding which animals to use for breeding - the father selects the ones who posses desirable characteristics. For example, if one of a farmer’s cow has a high milk yield the farmer chooses this cow for further breeding so is stock of cows become progressively better milk producers.
In nature this selection takes place ‘naturally’ - no one ‘decides’, the selection occurs simply because some traits give the possessor certain advantages. The possessor is more likely to survive, reproduce and pass on these traits. If the individual survives but does not reproduce, the traits do not remain in the gene pool.
A classic example of evolutionary psychology research is Buss’s (1994) survey of heterosexual male selection. Across all 37 countries studied, he found that men preferred good looks, youth and chastity, while women preferred good financial prospects, industriousness and dependability. These results suggest that certain behaviours and traits have evolved in both males and females since they promote better prospects for passing on favourable genes.
3) Neurochemistry & Brain physiology
Biological psychologists also recognise the role of chemicals in determining behaviour. At the synapse, signals are sent between neurones by chemicals called neurotransmitters. Imbalances in the number of neurotransmitters are associated with atypical behaviour, for example, too little serotonin has been associated with depression and too much dopamine has been associated with schizophrenia.
Research in this area helps us to understand the role of neurotransmitters. For example, recent research suggests that abnormally low levels of serotonin are linked to aggressive behaviour indicating that this neurotransmitter is important in regulating behaviour and impulse control ( Crockett et al., 2008).
Other types of chemicals found in the body which can also influence behaviour are called hormones. They are released into the bloodstream where they travel to the target cells which are activated by them specifically. Carre et al., (2006) found that high levels of testosterone are associated with defensiveness and territoriality in a study investigating the behaviour of ice hockey players.
Effects of brain physiology and neurochemistry
Interactions between regions of the brain help to control different functions, which biological psychologists assume to be significant in determining our actions. For instance, the occipital lobe is involved heavily in processing sight, along with the frontal lobe, which is thought to be involved in control and attention.
Electrical impulses enable an important means of internal communication that directs our behaviour, travelling around the brain and to/from the body via the nervous system. Impulses are transmitted between neurons (nerves) at synapses, junctions where neurotransmitters are released that inhibit or excite other neurons to achieve different responses. Neurochemical imbalances in the brain are often associated with abnormal behaviour - for instance, evidence suggests that the imbalance of dopamine (a neurochemical linked with the brain’s natural ‘pleasure’ system) are associated with mood disorders such as depression).
The endocrine system is a slower-acting communication system that regulates the circulation of hormones, released by glands into the bloodstream. For example, cortisol and adrenaline are key hormones that facilitate the flight or flight response, a key evolutionary survival mechanism whereby the body primes itself for imminent danger (e.g. increasing heart rate, initiating sweating to cool down, dilation of pupils, sharpened sense of hearing.)
Strength
The biological model uses the scientific method, through its use of experiments as a means of investigation. Experiments take place in highly controlled lab environments so that other researchers are able to replicate studies under the same conditions, therefore adding to the validity of the original findings if they can be reproduced. Early research into the brain relied upon case studies, but they were problematic due to researcher bias and a lack of control. However, sophisticated imaging and recording techniques has increased the researches validity and precision, making the research more objective and reliable as well as increasing the scientific credibility of researches.
Strength
Due to the approaches use of the scientific method, the approach provides clear predictions. This has led to significant applications of biological research in the real world. For example, research into the role of neurochemical imbalance in depression has led to the development of drug treatments, which correct this imbalance and minimise the symptoms. In addition, research into bodily rhythms has led to significant improvements in the working conditions of those people who must work shifts. This means the approach is useful and has enabled sufferers of conditions to live a relatively normal life.
Weakness
The biological approach is reductionist. Reductionism is the belief that complex human behaviour can be explained by breaking it down into its smallest parts, such as the action of genes or hormones. For example, many explanations of mental illnesses are reductionist because genes or neurochemical imbalances are believed to be the main cause of these illnesses. However, whilst a reductionist approach lends itself to scientific investigation, critics argue that we cannot fully understand a behaviour without also taking into account other factors that influence it. These include cognitive, emotional and cultural factors. Therefore, it may not offer comprehensive, valid explanations of behaviour as it is too narrow in scope.
However, the reductionist nature of this approach may lend itself well to scientific investigations. This is because it allows researchers to establish a cause of behaviours such as mental illnesses, assisting in diagnosis and treatments.
Weakness
The biological approach takes a determinist stance. It argues that human behaviour is governed/controlled by internal, biological causes. Causes we have no control over. This has huge implications for the legal system and wider society. The law states that offenders are seen as legally and morally responsible for their actions. Recent research suggesting a genetic basis for criminal behaviour had led to concerns about how this information might be used. It creates the danger that genes might be used as a convenient explanation for complicated human behaviour like aggression negating responsibility and offering a defence in court.
