Biological Approach
The
Biological
approach
Biological Approach
The biological approach has its roots in the much older science of biology, so
has a very long history. Modern research began in the 18th century with the
study of the nervous system and brain structure via autopsies. Techniques
have now moved on, with much more detailed research, for example using
brain scanning techniques.
Assumptions of the Biological approach
1. Functions of the brain are localised
The brain is a highly organised structure. The brain stem, which connects to
the spinal cord, is surrounded by the cerebral hemisphere. Although the brain
appears to be one structure, it is actually made up of two separate
hemispheres which are both very different when it comes to functioning.
The cortex (the outer layer) is only a few millimetres of the brain and is deeply
folded; it looks like hills or ‘valleys’.
Not only is the brain in 2 parts, it is then divided up into 4 lobes – each with
individual functions localised to it.
Biological Approach
 Frontal lobe –
 Temporal lobe –
 Parietal lobe –
 Occipital lobe –
2. Hormones affect our thinking, emotions and behaviour – the
endocrine system
Within the body there are two communication systems; the central nervous
system (a fast, electrical process) and the endocrine system (a slow, chemical
process which secretes hormones into the bloodstream.
Hormones are chemicals that travel around the body in the blood and affect
the action of target organs.
Q) Name one hormone and explain what it does.
Biological Approach
Theory: Selye’s General Adaptation Syndrome
One biological event that involves both the CNS and the endocrine system is
our body’s response to stress.
Q) What is stress?
Threats (also known as stressors) trigger stress; these can be internal or
external.
Q) What are internal stressors?
Q) What are external stressors?
Some situations we come across in life may be acceptable and we feel that we
can cope with them, however some stressors we find we can not cope, e.g. a
bull running towards us – do you think you could cope calmly in this situation?!
The changes that occur in our body are adaptive – they evolved to help us
survive.
Selye began investigating how rats responded to different stressful, unpleasant
situations and stimuli (e.g. heat). Rats produced the same kinds of response,
regardless of the stressor used. The responses reflected an attempt by the
body to cope. These responses included a range of physiological and
behavioural changes, e.g. breathing rate, dilated pupils and a change in blood
pressure. These all help an individual prepare for an emergency, such as fleeing
from danger or engaging in flight.
General: all rats reacted to stress in the same way
Adaptation: all rats adapted to the stressful situation
Syndrome: physiological and behavioural changes (also can cause death)
Biological Approach
Selye said we go through 3 stages when coping with stress:
Alarm reaction
Immediate changes to our bodies occur during this stage, they are caused by
the nervous system.
Messages are sent from sensory organs that have detected threats (such as
seeing a ghost or a car driving towards us). These messages are sent to our
autonomic nervous system (ANS).
There are two parts to our ANS:


Sympathetic –
Parasympathetic –
Q) What happens to our bodies during this stage?
If danger persists (its not going to go away any time soon), our body can not
by maintained by adrenaline alone. Other hormones are released to sustain
the bodies defence reactions. These hormones can remain high for a number
of months or years.
Resistance stage

Cortisol –

Thyroxine –
Other things we may experience in this stage:
However, elevated hormone levels themselves are damaging and can
ultimately lead to illness and exhaustion…
Selye observed that, what ever the cause of the stress, if the threat persisted
long enough, his rats became sick and ultimately died.
Exhaustion stage
The exhaustion stage reflects the bodies inability to sustain attempts to cope
under chronic stress.
One significant impact is on the ___________________ system.
Under prolonged stress, this system becomes _________ effective.
Humans may develop allergic reactions, asthma or eczema. They also have an
increased risk ______________ disease and stokes.
Biological Approach
B
C
A
The line in this diagram represents our ‘coping’ of stress. Initially, our coping
goes down (see A) because we are in shock (we don’t know what to do!). Once
we have assessed the situation we are able to cope with what is going on
around us (this is called resistance) and therefore our coping goes up (see B).
Our coping with stress can only hold out for so long, eventually our body will
fail us and our resistance will decrease (see C) – this is when we hit exhaustion.
Over time our body will give in, our immune system become less effective and
our heart is at risk.
Biological Approach
Applying the biological approach to therapy:
psychosurgery
The aims of psychosurgery:
Techniques in psychosurgery:
The leucotomy: first developed by Egas Moniz.
Moniz heard about a chimp who was very
distressed but was subdued by lesions on her
frontal lobes.
Biological Approach
The leucotomy was develop by Walter Freeman after he realised the original
procedure took far too long.
The lobotomy:
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‘Side effects and successes!’
Severe side effects of the operation were observed; complete loss of the
personality, apathy, and post-operative incontinence, as was shown by
President John Kennedy’s sister Rosemary, who was lobotomised and as a
result was reduced to having an infantile mentality as well as limitation in her
verbal ability.
Freeman and Moniz however believed that patients who had undergone this
operation left with lesser signs of disorders and in better health.
______% got better, _____% got worse, ______% showed no improvement
Current procedures:
Despite the vast amount of problems with psychosurgery, we do still perform it
today – in a far less dramatic way however!
Bilateral cingulotomy: introduced in 1948 as an
alternative to lobotomy. Today it is mainly used in the
treatment of depression and OCD.
In most cases, the procedure starts with taking an X-ray
and scan of the patient’s brain to identify the area that
requires treatment. Hole are then drilled into the skull
and fine electrodes are inserted (know as gamma knives),
the gamma knife then lesions the fibers and connections
in the brain that need to be removed.
Biological Approach
How does psychosurgery link back to the
assumptions of the approach?
Brain functions are localised….
As many brain functions are localised, damage to one particular area can have
specific effects on psychological functions. This idea underlies psychosurgery
because…
Localisation also explains how other functions remain unimpaired…
TIP: You can think of the
brain like a bike. You need
many pieces for it to work
properly. When piece is
damaged or missing, it will
not work anymore.
Biological Approach
The methodology for the biological approach
1) Laboratory experiments on animals
Research using animals provided most of the early psychological knowledge
about the structure and function of the nervous system, brain and hormones.
E.g. Selye’s GAS was based on research into rats.
E.g. Moniz’s ideas on psychosurgery were based on a single chimp.
However, most animal research is not based on isolated
examples but on the systematic testing of many animals
under controlled conditions, in which they are exposed to a
range of procedures.
Experiments seek to test the effect of an IV on a DV, and all other factors are
controlled.
IV in Selye’s GAS study =____________________________________________
DV in Selye’s GAS study =___________________________________________
Lab experiments are conducted in a highly controlled environment, where we
can be sure that what we have purposely changed is affecting our DV.
However, some additional variables can alter our results; these are called
extraneous variables.
Q) What are extraneous variables?
________________________________________________________________
____________________________________________________________
Biological Approach
Evaluation of laboratory experiments on animals
Strengths
1) Controlled environment
Weaknesses
1) There are some differences
between animals and humans
2) Animals are readily available and
cheap
3) More ethical than experimenting on 2) Ethical issues regarding animals
humans
4) We share the same basic elements
with animals
Biological Approach
2) Brain scanning
There are two types of brain scanning techniques that you need to be aware of
a) Structural scanning (MRI)
b) Functional scanning (PET)
Structural scanning
These provide detailed images of brains without having to actually cut it open.
We can look at structural differences between people, e.g. ‘normal’ people and
‘abnormal’ people.
An example of schizophrenic patients…
Previous to scanning techniques, we had to wait for an individual to pass away
before we could look at their brain and determine whether brain abnormalities
caused death. Today, we can look inside an individuals skull without having to
be invasive (cutting the individual open). MRI scans look like a black and white
photograph of a slice of the brain. It shows us the structure of our brain,
highlighting in white where ‘matter’ is. MRI’s can also show us structural
damage and any abnormalities (tumours).
Biological Approach
Functional scanning
These scans identify the parts of the brain that are more or less active when
we are doing something.
This allows researchers to link brain activity and localisation to behaviour. For
example, where does our language come from? Where are our emotions?
Where is our artistic flare?
In PET scans, radioactive molecules are injected into the bloodstream. These
chemicals are used by active brain tissues. It takes about 1 minute for the
chemical to reach the brain and last for about 15 minutes. The radioactivity is
picked up by the scanner and produces colourful images (depending on the
strength of the activity).
Biological Approach
Evaluation of the Biological Approach
Strengths:
1. Biological approach is a good science
The biological approach is seen to be scientific as it uses scientific methods
such as lab experiments and scanners. These are both reliable methods of
investigation and can be easily replicated.
2. Explanations from the biological approach have useful applications
Weaknesses:
1. The biological approach is reductionist:
The biological approach focuses on influences such as hormones and
brain structure alone, it does not take into account environmental factors
such as media or family influences on our behaviour. Is, for example,
aggression always due to hormones or can we learn aggression from
parents?
2. Psychosurgery only treats symptoms
Biological Approach
Nature Vs Nurture:
Determinism:
Key issues
and
debates
Reductionism:
Psychology as a science:
Biological Approach
What can be asked?
1
a) Outline two assumptions of the biological approach (4)
b) Describe Selye’s General Adaptation Syndrome as an explanation of stress (8)
2.
Describe how the biological approach has been applied to one therapy (12)
3.
a) Evaluate two strengths of the approach (6)
b) Evaluate two weaknesses of the approach (6)
4.
Compare and contrast the biological and psychodynamic approaches in terms of
similarities and differences (12)
5.
Explain and evaluate the methodology used by the biological approach (12)