Download Outline of Biological Approach

Specification: The biological approach: the influence of genes, biological structures and
neurochemistry on behaviour. Genotype and phenotype, genetic basis of behaviour, evolution
and behaviour
Assumptions:
 From a biological perspective, the mind lives in the brain – meaning that all thoughts,
feelings and behaviour ultimately have a physical basis.
 Biological psychologists believe that the genes an individual possesses influence his or
her behaviour.
 This also means that there is a belief in the process of evolution. It is believed that
behaviour evolves the same way as physical characteristics through the process of
evolutionary adaptation and natural selection.
 The central nervous system which comprises the brain and spinal cord is an important
system as the brain is seen as the main focus when explaining behaviour. It is seen to be
the origin of how the world is seen and acted upon by an individual.
 Neurochemistry is also important in explaining behaviour. Varying levels of the chemicals
found both in the brain (neurotransmitters) and the body (hormones) are thought by
biological psychologists to be related to an individual’s behaviour. They are believed to
influence reactions to the environment.
The Genetic Basis of Behaviour:
 Biological psychologists believe that the genes an individual possess
influence his/her behaviour.
 Each individual is typically born with 23 pairs of chromosomes
which have been inherited from their birth parents.
 These are our genotype and form the basis for our behaviour.
 Biological psychologists believe our genes carry instructions for particular
characteristics such as intelligence, personality and mental disorders.
 How these characteristics develop depends partly on the interaction with other genes
and the environment.
Twin Studies:
 Twin studies are used to determine the likelihood that certain
traits have a genetic basis by comparing the concordance rate
(the likelihood of both twins having the disorder) between
identical and non-identical twins.
 If an identical (monozygotic – MZ) twin is found to have a
higher concordance rate than non-identical (dizygotic – DZ) twin
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 siblings).
Genotype and Phenotype:
 The genotype is an individual’s actual genetic make-up which occurs at conception and
provides the genetic code for how that individual will develop. The genotype dictates such
characteristics as eye and hair colour.
 The phenotype of an individual is the product of what happens when the genotype interacts
with the environment. It is the way the genes are expressed.
 E.g. with a physical characteristic such as height
the genotype dictates the maximum height an individual can
reach but environmental factors such as nutrition will affect
how likely the person is to achieve their potential height.
 Hair is another good example. An individual's genes
determines whether or not they have hair on their head, but
how long this hair remains depends on environmental factors,
such as excess sunlight, chemicals used on the head, or poor diet. This shows that
phenotype is influenced by the environment
 This is the same for psychological characteristics in that there may be a genetic
predisposition to a behaviour but it may not express itself due to the environment which
inhibits its development.
 This illustrates what many biological psychologists would accept, that much of human
behaviour depends upon an interaction between inherited factors (nature) and the
environment (nurture).
Evolution and behaviour:
 Biological psychologists would argue certain human
behaviours and physical characteristics exist
because they are adaptive (aid survival).
 For example, aggression can be seen as an adaptive
behaviour. This is because at some point aggression
will have been advantageous for our ancestors. This may be because aggression
creates protection for the family and resources.
 This trait will be seen as attractive to the opposite sex therefore making the likelihood of
passing on the gene much greater. Over time the aggression gene will become more
widespread. Therefore certain behaviours have evolved because they are adaptive.
The influence of Neurochemistry on behaviour:
 Neurochemistry is the biochemistry of the central nervous
system. Hormones are the chemicals which travel through the
blood.
 However in the brain, the transmission of chemicals is via the
cerebral fluid. These chemicals are called neurotransmitters
and are seen to be important by biological psychologists as
they are thought to affect behaviour.
 An example of this is that high levels of a neurotransmitter
called dopamine are related to schizophrenia, (we will look at
this more in biopsychology)
Remember: As with ALL the approaches, only learn the 3 or 4 evaluation
points you understand the most for AS and leave the rest until 2nd year.
Task: Highlight strengths & weaknesses:
The biological approach adopts scientific methods for investigation using measures which are
largely objective (not subject to opinion) such as brain scanning and measuring biochemical levels.
It is possible to accurately measure biological and neural processes in ways not open to bias
therefore supporting the biological approach as it is based on reliable data.
It is one the strongest supporters of the nature perspective in the nature-nurture debate as it
argues for genetic influence on behaviour. However, what the biological approach does not take
into account is that twins and family members are exposed to the same environment. This means
that findings could just as easily be interpreted as supporting nurture rather than nature as it
could be that the behaviour has been learned through the environment rather shared through
genes.
A real strength of the biological approach is its real-world application. Increased understanding
of biochemical processes in the brain has led to the development of psychoactive drugs that treat
serious mental illnesses such as depression (anti-depressants increase serotonin production).
Although these drugs are not effective in all patients, they are revolutionised treatment for
many. This is a strength of the biological approach as it means that sufferers are able to manage
their condition and live relatively normal life, rather than remain in hospital.
It is argued some of the explanations are too simplistic and do not do the complexity of human
behaviour justice. This means they are reductionist as they can often fail to acknowledge the role
of the environment in behaviour.
The biological approach is determinist in the sense that it sees human behaviour as governed by
internal, biological causes over which we have no control. This is a criticism of the biological
approach as it says we are purely governed by our genetics and don’t have any control over our
behaviour which is untrue.