The Biological approach
Summary:
 Human behaviour can be explained
and understood at the level of
functioning of biological systems
Biology refers to the study of living organisms (Bio- Greek for
‘living’).
The biological approach aims to explain all human behaviour and
experience in terms of physical bodily processes.
For example; when you feel stressed, this is
accompanied by sensations such as heart
pounding, your palms sweating and so on. These
are physical symptoms created by the activation
of your nervous system. Your entire experience
of stress is caused by biological processes!
Included within the biological approach are the following:
*Physiological psychology, which is concerned with the functioning
of the body.
*The nativist approach, which is concerned with an individual’s
genetic nature.
*The medical approach, a term used to describe how mental
disorders are explained in the same way that the medical profession
explains physical illnesses.
All three of these fall under the umbrella term biological approach
and can, and are, sometimes used instead of the biological approach.
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The first assumption of the
biological approach is that
behaviour can be explained in
terms of different areas of the
brain.
Many different areas of the
human brain have been identified
as specialised for certain
functions. The brain is actually
made of many parts, but the main
part we can see is the big grey
wrinkled (or folded) part covering the surface; this is called the
cerebral cortex. This is the region of the brain that houses the
‘higher cognitive functions’. It is then divided into four lobes, each
with specialised jobs.
Underneath the cortex are the subcortical structures, and these
too all have jobs governing human behaviour.
Research task:
Find out the function of the following parts of the brain:
Frontal lobe
Occipital lobe
Parietal lobe
Temporal lobe
Corpus callosum
Brain stem
Spinal cord
Hippocampus
Hypothalamus
Thalamus
Cerebellum
Amygdala
Pineal gland
Pituitary gland
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The second assumption of the biological approach, sometimes called
the nativist approach, is that human behaviour can also be
explained or understood at a genetic level.
Much like certain genetic physical characteristics can be inherited
from your biological parents; the biological approach applies this
same idea to behaviour. i.e. some behaviours can be inherited from
your parents.
Task:
What are some of the physical characteristics people can inherit
from their parents?
Are there any other characteristics you can think of that some
people believe are inherited?
Some characteristics are determined by one gene (e.g. eye colour),
whereas for most characteristics (e.g. intelligence), many genes are
involved.
Biological psychologists mostly agree that genes actually contribute
to a predisposition to behave in a certain manner, rather than
determining behaviour. This means a person does not necessarily
behave in a certain way just because they have the genes, but it is
instead a complicated relationship involving their interaction with
their environment and their life experiences.
An example of this would be mental illness: Not everyone who has
relatives who have depression will develop depression themselves.
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The third assumption is that human behaviour can be explained in
terms of chemicals in the body; specifically hormones and
neurotransmitters.
Task:
Think how some of the following chemicals (drugs) affect people’s
behaviour:
Caffeine
Cocaine
Alcohol
Ecstasy
Heroin
LSD
Marijuana
Methamphetamine
Technically a chemical is any substance that has an effect on living
cells. Because this could mean literally anything, including water;
psychologists are somewhat more restrictive in their terminology.
The study of the effects of drugs on human behaviour is an entire
branch of biological psychology called psychopharmacology.
We already know that foreign substances introduced to the body will
have an effect on that person’s behaviour.
However, biological psychologists are also very interested in the
effects of substances that are native to the human body.
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Hormones are biochemical substances that are produced in one part
of the body and circulate in the blood, having an effect on a target
organ(s).
They are naturally produced in very large quantities, but can
disappear very quickly. Their affects can be slow, when compared
with other bodily functions, but their affects are very powerful.
Examples of hormones include;
testosterone (the male hormone),
oestrogen (the female hormone)
and adrenalin (the stress hormone).
Task:
List some of the hormones in the human body, and their effects
(both physical and behavioural).
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Neurotransmitters are also biochemicals in the human body that can
have an effect on human behaviour.
The human body is a remarkably complex system; composed of
trillions of individual cells, many with specialised jobs and nothing
else (e.g. only stomach cells produce digestive secretions, only heart
cells beat at a steady rhythm).
Coordinating the activity of the body’s many
systems requires communication, which is one of
the key functions of the specialised cells that
make up the nervous system. These cells are
called nerve cells, or neurons. The body depends
on these cells being able to communicate quickly
with one another (far quicker than hormones
would ever be able to!).
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Neurons are electrically excitable cells. They have many branches at
the end of each one (called dendrites) so that each neuron can
communicate with many others. Each neuron communicates with
another at a synapse, where their signal is relayed by the release of
a chemical (a neurotransmitter).
These neurotransmitters are released from presynaptic vesicles in
one neuron and will either stimulate or inhibit receptors in the next
neuron. The synaptic gap between each neuron is about 20nm
(nanometers) wide.
Different neurotransmitters have different effects.
Some common neurotransmitters are: dopamine, serotonin,
adrenaline and GABA.
Research Task:
Find out the effects of each of these neurotransmitters (too much
or too little).
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The fourth assumption of the biological approach is that
psychological problems can be treated in the same way as
physical disorders.
The medical model of mental illness assumes that all mental
disorders have a physical cause.
It also assumes that mental illnesses can be
described in terms of clusters of symptoms;
and symptoms can be identified, leading to
the diagnosis of an illness. The various
symptoms, and the mental illnesses they may
indicate, are listed in a book called the
Diagnostic Statistical Manual (DSM). Every
decade or so, it gets updated as new mental
illnesses are ‘discovered’ or ‘disproven’.
We are currently up the DSM-5.
Following successful diagnosis, this can lead to appropriate physical
treatments (e.g. chemotherapy)
Task:
Can you name any mental illnesses?
Can you name any drugs that are prescribed to people with mental
illnesses?
Do you know how this drug helps with their illness?
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Strengths of the biological approach
 The biological approach has proved valuable in terms of the
use of chemotherapy to treat various mental disorders
(schizophrenia, depression etc.)
In addition genetic counselling for
prospective parents is a result of our
current understanding of the links
between genes and behaviour. For
some parents this is an enormous
relief where, for example, they carry
a genetic susceptibility for a fatal
disease. However genetic counselling
raises many ethical problems in
relation to the concept of designer
babies.
 Explanations within the biological approach are reductionist,
but this is not a bad thing, as these biological explanations
have often proved useful. Examples include; the activationsynthesis theory of dreaming, and theories of schizophrenia
which emphasise brain structure and/or brain chemistry.
 The biological approach has proved
successful in showing that genetic factors
play a role in explaining individual
differences in intelligence (and in
explaining why some individuals are more
likely than others to develop certain
mental disorders)
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Weaknesses of the biological approach
 The reductionist nature of the biological approach means it is
oversimplified. We can’t obtain a complete understanding of
human behaviour just by focusing only on
biological factors.
For example, various psychological, social
and cultural factors influence the
development of mental disorders such as
depression and anxiety, and these factors
are ignored within the biological approach.
 Biological explanations are more
appropriate for some kinds of behaviour
(eg: vision) than other kinds of where
higher order thinking is involved (eg:
emotion, reasoning)
 Biological explanations are deterministic, and often involve
focussing on genetic factors. However, the influence of genetic
factors on behaviour is typically
quite indirect.
For example, Plomin et al (1990)
found in a twin study that
genetic factors influence
television watching, but it is
very difficult to work out
exactly how genes have this
effect.
 The biological approach exaggerates the importance of
genetic factors in determining behaviour while minimising the
importance of environmental factors.
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 The way biological research is conducted means that only a few
individuals are studied, and it is assumed that everyone’s
biological systems work in much the same way. In fact,
research on biological systems has tended to use male rather
than female participants. The reason being that female
hormone cycles may interfere with the biological research.
Such a bias could however produce a rather erroneous
picture of behaviour: one with a male bias.
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Methodology
Some researchers use several different methods. Some researchers
use physiological measures to increase our understanding of human
behaviour. For example, the use of EEG provided evidence for
different stages of sleep and showed that there is an association
between dreaming and REM sleep.
A common way of assessing the importance of genetic factors is by
studying identical and fraternal twins. If identical twins are more
similar than fraternal twins in behaviour, this supports the notion
that genetic factors are important.
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Advocates of the medical model approach to mental disorders carry
out research in which they compare patients with some mental
disorder with ‘normal’ individuals in order
to see whether there are any significant
differences in bodily functioning or
structures.
For example the brain volume of
schizophrenics is less than that of normal
controls and schizophrenics also have
enlarged ventricles in the brain.
Biological psychologists would also use case studies to support their
theories of what each brain structures role is.
The best way of finding out what each part of the brain does is to
find someone who doesn’t have it, and find out what they can’t do.
We can then logically assume that what they are now unable to do is
what that part of their brain was
for.
Ethically, it would be extremely
wrong to start performing surgery
on people just to find out what
parts of their brain do, they have
to rely on people who have suffered
brain damage through accidents.
There are many famous case studies in psychology. These include;
Clive Wearing, Phineas Gage, and David Reimer.
End of approach Task
1) Outline the biological approach
and give 2 strengths and 2 weaknesses of this approach.
2) Describe the methodology used in the biological approach.
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