5.5 The Biological Approach

Assumptions of approach

-Suggests that everything psychological is at first biological, we must look at biological structures and processes within the body

-All thoughts, feelings and behaviour ultimately have a physical basis.

The neurochemical basis of behaviour

Neurochemistry refers to the action of the chemicals in the brain. Much of our thought and behaviour relies on chemical transmitters. An imbalance of neurochemicals in the brain has been implicated as possible causes of mental disorder. For example overproduction of dopamine in schizophrenia.

The genetic basis of behaviour

Psychological characteristics such as intelligence are inherited the same way as height or eye colour. Twin studies are used to investigate whether certain psychological characteristics have a genetic basis. This is achieved by analysing concordance rates- extent to which the twins share the same characteristic.

Genotype

A persons actual genetic make-up

Phenotype

The way that genes are expressed through physical, behavioural and psychological characteristics.

-Despite having the same genes, the way identical twins’ genes are expressed is different.

Genes

They make up chromosomes and consists of DNA which codes the physical features of an organism and psychological features. Genes are transmitted from parents to offspring.

Evolution

The changes in inherited characteristics in a biological population over successive generation.

Evaluation of the assumptions and influence of genes: Strengths

-It has real world application. There’s been an increased understanding of neurochemical processes in the brain . This has promoted the treatment of clinical depression using antidepressant drugs that increase the levels of neurotransmitter serotonin at synapses in the brain. This enables people with depression to manage their symptoms.

-The approach uses scientific methods of investigation. The approach makes use of a range of precise and highly objective methods. Including scanning techniques such as MRISs and EEGs. This enables the investigation of physiological and neural processes. These are objective and reliable data sources.

Evaluation of the assumptions and influence of genes: Limitations

-Although antidepressant drugs are successful for many patients, they do not work for everyone. For example in a recent study by Andrea Cipriani et al they compared 21 antidepressant drugs and found wide variations in their effectiveness. Brain chemistry may not account for all cases.

-The biological approach is determinist as it sees human behaviour as governed by internal, genetics which we have no control over. However, an individuals phenotype is heavily influenced by the environment. A purely genetic argument could become problematic when we consider things like crime. Could a violent criminal claim that their wrongdoing was down to a ‘crime gene’. This suggests the biological view is too simplistic and ignores factors like the environment.

Central Nervous System

-Consists of the brain and the spinal cord. It receives, sends and responds to sensory information.

Peripheral Nervous System

This relays information between the body and the brain. This information includes involuntary responses such as breathing and heartbeat as well as sensory information and control of voluntary movement.

The Endocrine System

This a chemical messaging syetmthax operates throughout the body. The system secretes hormones into the bloodstream from different glands e.g. the Pituitary gland.

Example of hormones: adrenaline, testosterone, oxytocin.

The Brain

The brain is made up of different regions:

Temporal Lobe- controls the hearing and speech comprehenhsion

Frontal Lobe- This lobe is linked to voluntary movement and expressive language. The prefrontal cortex in particular is linked to executive functioning e.g. impulse control.

Cerebellum- This lobe receives information from the spinal cord, sensory systems and other parts of the brain. It regulates balance and motor movements.

Neurotransmitters

Chemical messengers and neural processes associated with the nervous system

Evolution and Behaviour

The evolutionary approach to explaining behaviour looks at how and why specific human traits have evolved via the process of natural selection.

Example:

Aggression- fight of predators and enemies

Memory- location of food sources

Language- communicate to tribe members

Mate selection- bear healthy offspring

Due to natural selection, behaviours and traits which are useful for survival and reproduction are retained- those that are not eventually die out.

Nature- Nurture debate

Nature is what we think of as pre-wiring and is influenced by genetic inheritance and other biological factors whereas nurture is generally taken as the influence of external factors after conception- life experiences and learning of an individual.

An extreme biological approach takes the nature argument.

Evaluation of biological structures and neurochemistry: Strengths

-Research into biological structure is objective. Zak et al measured testosterone levels in blood samples and Maguire et al used MRI scans to investigate the role of the hippocampus in spatial navigation. This means they can be tested across time for for consistency and they have good reliability.

-Curtis et al found that people showed higher levels of disgust for disease-salient images than neutral images. Disgust is an evolutionary mechanism as it prevents people from investigating toxic material. Therefore if people have an innate disgust response to rotten food this lends validity to the idea that humans are biologically programmed for survival.

Evaluation of biological structures and neurochemistry: Limitations

-The research is overly reductionist because for example levels of testosterone cannot alone account for a lack of prosocial behaviour, other factors like personality and upbringing can explain this.

-Some behaviours aren’t advantageous anymore, for example we don’t have to fight competitors for food and so we don’t need aggression and it is more likely to get us into trouble.