Biological Approach Flashcards
Assumptions of the biological approach
1) to fully understand human behaviour we must look at biological structures and processes within the body eg nervous system, neurochemistry and hormones
2) an understanding of the brain structure and brain function can explain our thoughts, feelings and behaviour. all thoughts, feelings and behaviour have a physical basis
3) biopsychologists agree that genes influence behaviour. furthermore because the genes that we inherit are from our distant ancestors, many biopsychologists think that behaviour and psychological characteristics have evolutionary explanations
The Influence of Genes on Behaviour
- the body is made up of trillions of cells
*within most cells in the human body is a nucleus
- the nucleus of every cell(apart from sex cells) contains 46 structures called chromosomes (23 pairs of chromosomes from their parents-genotype- form the basis for our development
- chromosomes are made up of a complex chemical called DNA
- the DNA on each chromosome carries the units of information called genes
- our genes interact with the environment to influence every aspect of our bodily structure and function
There are two key terms that help explain how genetics can influence the development of an individual:
Genotype- * an individuals genetic makeup
*occurs at conception and provides the genetic code for how that individual will develop
* each individual is thought to have approx 100,000 genes
*genotype dictates characteristics such as eye and hair colour
* each individual apart from identical twins has a genotype that is unique to them
Phenotype- * the product of what happens when the genotype interacts with the environment
* with a physical characteristic such as height the genotype dictates the height an individual can reach- but environmental factors such as nutrition will affect how likely the person is to achieve their potential height
The Genetic Basis of Behaviour
We know that physical characteristics such as height, bone structure, hair and eye colour are inherited.
Behavioural geneticists are interested in the degree to which psychological characteristics such as ability, personality and emotional stability are transmitted from parent to offspring.
some of the well researched human psychological characteristics thought to be influenced by genes are: intelligence, psychological disorders and male and female differences.
The Influence of Biological Structures on Behaviour
The biological approach believes that an understanding of biological structures and their associated functions can explain psychological processes and characteristics.
The human body is a collection of systems which integrate to help us live. There are key structures within these systems which are particularly useful in explaining the behaviour of an individual.
Neurons- neurons are the basic ‘building blocks’ of the nervous system. they are nerve cells which are specialised to receive, process and transmit information to other cells within the body.
The Central Nervous system - made up of the brain and the spinal cord
- the brain- can be subdivided into many different areas and structures which are thought to be responsible for certain behaviours, eg frontal lobes are used for speech thought and learning.
the brain relies on a large number of chemicals called neurotransmitters to send signals between neurons
too much or too little of these chemicals can result in over or under activity in various parts of the brain which can result in changes to thinking, feeling and behaviour
- the spinal cord receives and passes message to and from the brain, and connects to nerves in the peripheral nervous system.
The Peripheral Nervous system
made up of neurons that transmit messages or information to and from the central nervous system- it has two subsystems- somatic and autonomic nervous systems
Somatic Nervous System- transmits information received by the senses to the central nervous system and sends messages from the central nervous system to the muscles
Autonomic Nervous System- divided in 2- sympathetic nervous system which increases bodily activities(response to fight to flight) and parasympathetic nervous system (which maintains or decreases bodily activities)
The Influence of Neurochemistry on Behaviour
neurotransmitters- these are chemical messengers in the brain - the transmission of these chemicals is via the cerebral fluid
when a nerve impulse reaches the end of a neutron- a chemical called a neurotransmitter is released. it travels from one neutron to the next across a junction called a synapse
there are many different types of neurotransmitters, some trigger the receiving neuron to send an impulse and some stop it from doing so. Those neuron transmitters that trigger nerve impulses in the receiving neutron and stimulate the brain into action are called excitatory neurotransmitters. Those that inhabit nerve impulses in order to calm the brain and balance mood are called inhibitory neurotransmitters.
These chemicals are seen to be very important by biological psychologists as they are thought to affect behaviour. Dopamine is an excitatory neurotransmitter that is associated with our ‘drive’ and motivation. High levels of dopamine are linked to schizophrenia. Serotonin is an inhibitory transmitter, adequate amounts of which are necessary to maintain a stable mood. Low levels of serotonin are related to depression
Hormones- hormones are biochemical substances that are produced by glands in the endocrine system . In response to a signal from the brain, hormones are secreted directly into the bloodstream by the endocrine glands, where they travel to their ‘target cells’ and exert their influence by stimulating receptors on the surface of or inside cells.
The Evolutionary Theory of Behaviour
The main principle of this theory is that any genetically determined behaviour that enhances an individuals survival and reproduction will be passed on in genes to future generations, eg be naturally selected
Natural selection occurs simply because some genetically inherited traits give the possessor some advantage, the possessor is more likely to survive, reproduce and pass on these genes/traits to future generations. If the individual survives but does not reproduce, the traits do not get passed on to future generations
Evaluation of the Biological Approach - Deterministic
P- the biological approach has been criticised for being deterministic
E- the biological approach is deterministic in the sense that it sees human behaviour as being controlled by internal, biological causes meaning we have no free will. Retz et al concluded that the 5-HTTLPR gene, which controls levels of serotonin in the synapse, is associated with violent behaviour in male criminals. This indicates that the the violence is part of the criminals biology so they do not choose to act this way
L- this is a weakness because it has implications for the legal system and wider society. One of the rules of law is that offenders are legally and morally responsible for their actions. If we believe the biological approach offenders are not morally responsible or to blame as they are controlled by their genes.
Evaluation of the Biological Approach- supporting evidence
P- there are many pieces of supporting evidence for the biological approach
E- supporting research for the biological approach come from twin studies using biological equipment such as PET scans
L- this is a strength because having supporting research such as this adds validity and creditability to the biological approach, particularly the genetic explanation
Evaluation of the Biological Approach- real life application
P- a strength of the biological approach is that biological research has led to many treatments being developed to treat psychological disorders
E- research into biomedical processes in the brain has lead to the development of drug treatments. medication to treat serious mental illnesses such as schizophrenia and depression have been developed. Although these drugs are not effective for all patients they have revolutionised treatment for many.
L- this is a strength because it means that sufferers are able to manage their condition and live a relatively normal life, rather than remain in hospital
Evaluation of biological approach - methods
P- the methods used by the biological approach are scientific lab studies and studies that involves scientific/biological equipment
E- in order to investigate fully the genetic and biological basis of behaviour, the biological approach makes use of a range of precise and highly scientific methods which are reliable and objective. Raine et al (97) used PET scans to compare brain activity in murders and ‘normal’ individuals. They found differences in the brain such as the prefrontal cortex and the amygdala, regions associated with aggressive behaviour
L- this is a strength because by emphasising the importance of scientific processes and their reliance on the scientific method the biological approach gives psychology greater creditability and status as a science
How do biological psychologists study behaviour ? Biological Research - Twin Studies
Twin Studies
Key term- concordance rate: the extent in which both twins in a sample share a certain disorder/trait/behaviour
the biological approach uses twin studies to measure the concordance rates between identical and non identical twins to help understand the genetic basis of certain behaviours. Identical twins(MZ) are 100% genetically similar, non identical twins are 50% genetically similar. The likelihood of both identical twins having the same disorder compared to the likelihood of both non identical twins(DZ) gives an indication of how much the behaviour may be genetic. If MZ twins show a higher concordance rate than DZ twins then it is argued it is a genetic explanation.
in a study of intelligence Bouchard and McGue (1981) compiled the results of 111 studies and found the following concordance rates
MZ twins raised together-87%
MZ twins raised apart- 72%
DZ twins raised together- 60%
DZ twins raised apart- 47%
Evaluation of twin studies - Perfect Participants
P- identical twins share 100% of genes , and non identical twins share 50% of their genes
E- eg in the above study it can be quite clearly seen that IQ has a genetic basis due to their being a 27% difference between the concordance rates of identical and non identical twins
L- this is a strength because they are an ideal sample and provide useful data when trying to support the biological approach
Evaluation of twin studies- Same environment
P- there is a problem with twin studies that is very difficult to ignore. identical twins are often exposed to similar environmental conditions when they are being raised. often parents dress them the same and people get confused with them as they look identical, this does not happen with non identical twins
E- eg the 87% of identical twins in the study above probably would have shared very similar experiences. Perhaps these environmental stimuli are the reason they had higher concordance rates than non identical twins
L- this is a weakness because it means that findings could just as easily be interpreted as supporting nurture rather than nature.
Pet Scan Study
Raine et al (1997) used PET scans to compare brain activity in murderers and ‘normal’ individuals. They found differences in areas of the brain such as the prefrontal cortex and the amygdala, regions associated with aggressive behaviour
Evaluation of Scientific Equipment and Scanning techniques - Objective data
P- these methods favoured by biopsychologists are precise, objective and highly scientific
E- eg in raines study above the psychologists were reading a PET scan (coloured x ray picture). This means the data was objective and not open to subjective interpretation
L- this is a strength because it means the results will therefore add validity to the biological approach. additionally due to the biological equipment being so specific, this will increase the inter rater reliability, as all of the psychologists will interpret the objective results the same.
Evaluation of the Scientific Equipment and Scanning Techniques
P-PET scans have weaknesses, they are extremely costly, and the patient has to be injected with a radioactive substance and are less accurate than MRI scans
E- eg in Raines study this could have been quite an invasive method for the participants, therefore their brain could be analysed they will have had a radioactive substance injected into them
L- This is a weakness because it could cause an already stressed patient even more stress
