1. The biological explanation for aggression says it is caused by genetic factors and differences in biological makeup. Twin studies have found a 50% genetic correlation for aggression between identical twins. 2. Research has linked the MAOA gene, which regulates serotonin levels in the brain, to aggression. Those with low MAOA expression have been shown to display more aggression, especially when exposed to childhood abuse. 3. Brain imaging studies have helped identify areas involved in memory, sleep, and language by examining patients with brain damage or through scans like PET scans during tasks. This has advanced understanding of brain functions.

1. BIOLOGICAL
APPRAOCH

2. GENES
The biological explanations of aggression say that aggression is caused by differences in
the biological make-up of individuals.One example of these biological differences that
could cause aggression is genetic factors. We are unsure of why there may be a link
between genetics and aggression; however research has found a correlation

3. ■ Twin Studies – Monozygotic (MZ) twins share all of their genetic information whilst dizygotic twins
(DZ) share 50%. If MZ twins are more alike in terms of aggressive behaviour than DZ twins, then this
should be due to genes rather than environment. It is much harder to study aggressive behaviour than
criminal behaviour, so few studies have tried to measure aggressive behaviour directly. However,
Coccaro did use twins to study aggressive behaviour and found that 50% of the aggression towards to
each other could be attributed to genetic factors
■ Twin studies provide geneticists with a kind of natural experiment in which the behavioural likeness of
identical twins (whose genetic relatedness is 1.0) can be compared with the resemblance of dizygotic
twins (whose genetic relatedness is 0.5).
■ In other words, if heredity (i.e. genetics) affects a given trait or behaviour, then identical twins should
show a greater similarity for that trait compared to fraternal (non-identical) twins.
■ There are two types of twins:
■ Monozygotic = identical twins (share 100% genetic information).
■ Dizygotic = non-identical twins (share 50% genetic information, similar to siblings).

4. ■ Research using twin studies looks for the degree of concordance (or similarity) between identical and
fraternal (i.e. non-identical) twins.Twins are concordant for a trait if both or neither of the twins
exhibits the trait.Twins are said to be disconcordant for a trait if one shows it and the other does not.
■ Identical twins have the same genetic make-up, and fraternal twins have just 50 per cent of genes in
common.Thus, if concordance rates (which can range from 0 to 100) are significantly higher for
identical twins than for fraternal twins, then this is evidence that genetics play an important role in
the expression of that particular behaviour.
■ Bouchard and McGue (1981) conducted a review of 111 worldwide studies which compared the IQ of
family members.The correlation figures below represent the average degree of similarity between
the two people (the higher the similarity the more similar the IQ scores).
■ Identical twins raised together = .86 (correlation).
■ Identical twins raised apart = .72
■ Non-identical twins reared together = .60
■ Siblings reared together = .47
■ Siblings reared apart = .24
■ Cousins = .15
■ However, there are methodological flaws which reduce the validity of twin studies. For example,
Bouchard and McGue included many poorly performed and biased studies in their meta-analysis.
Also, studies comparing the behavior of twin raised apart have been criticized as the twins often share
similar environments and are sometimes raised by non-parental family member.

5. ■ Adoption studies – One problem when studying twins is that twins will often be
brought up together in a similar way, so it is hard to say whether the concordance
rates are caused by genetic or environmental factors.To solve this problem
psychologists can carry out adoption studies where they observe the levels of
aggressive behaviour in adopted children and their biological parents. If there is a high
correlation between aggression levels of the two you can say it is genetics not the
environment that caused this aggression. Hutchings and Mednick (1975) studied
14,000 adopted children and found that a high proportion of boys with criminal
convictions had biological parents with criminal convictions too, suggesting a link
between aggression and genetics.

6. ■ Genetic explanation for aggression
■ MAOA – The gene MAOA is responsible for the regulation of serotonin in the brain.
Low levels of serotonin are thought to lead to aggressive behaviour, so a problem with
MAOA could lead to aggressive behaviour. Brunner (1993) found that in a Dutch family
with a history of serious aggressive crime the men had abnormally low levels of
MAOA, supporting this explanation
■ Gene-environment interaction –This explanation says that it isn’t just genetics that
causes aggression, it is a combination of the genetics and the environment that
someone lives in that causes aggression. For example a study found that in a sample of
children who had low levels of MAOA it was only the children who were maltreated
that displayed antisocial behaviour

7. ■ Physiology: how the nervous system and hormones work, how the brain functions,
how changes in structure and/or function can affect behavior. For example, we could
ask how prescribed drugs to treat depression affect behavior through their interaction
with the nervous system.

8. ■
■ Genes and Serotonin
■ It has been suggested that males with an extraY chromosome were predisposed to
violent crime. Individuals with an XYY chromosome arrangements are above average
height and below average intelligence. It might be the low intelligence that accounts
for their over representation in prison populations. It has also been argued amongst
twins that there's a 52% concordance rate in criminality between identical twins,
suggesting that criminality is genetically transmitted.
■ Serotonin is a neurotransmitter that is believed to play an important role in the
regulation of anger and aggression; lower than normal levels can lead to depression.
Serotonin is also involved in the regulating and inhibiting appropriate behaviours, it is
also know as the 'feel good' chemical.The study below examines the effect of an
imbalance of a particular enzyme MAOA can have on serotonin levels and the effect
this may have on behaviour.

9. ■ Brunner
■ Genes and Serotonin
■ Aim:To document a family from the Netherlands where 5 males exhibited impulsive aggression and
borderline mental retardation.
■ Sample: 5 males from one family, studied due to violent, impulsive aggressive tendencies These
males have been involved in a range of crimes such as arson, attempted rape and exhibitionism.
■ Procedure: Data was collected from the analysis of urine samples over a 24 hour period.
■ Findings:
■ Test showed a deficit in the MAOA enzyme
■ In each of the 5 males, there was a point mutation on the x-chromosome of the gene responsible for
the production of MAOA, which in turn is responsible for the production of serotonin.
■ Conclusion: Impaired serotonin levels is likely to be responsible for the mental retardation and this
could be linked with aggressive behaviour and inability for self control.
■ Evaluation:

11. STUDY OFTHE
BRAIN

12. Studying the brain
■ It is important to appreciate that the human brain is an extremely complicated piece
of biological machinery. Scientists have only just “scratched the surface” of
understanding the many functions of the workings of the human brain.The brain can
influence many types of behavior.
■ In addition to studying brain damaged patients we can find out about the working of
the brain in three other ways

13. ■ 1. Neuro Surgery
■ We know so little about the brain and its functions are so closely integrated that brain
surgery is usually only attempted as a last resort. H.M. suffered such devastating
epileptic fits that in the end a surgical technique that had never been used before was
tried out.
■ This technique cured his epilepsy, but in the process the hippocampus had to be
removed (this is part of the limbic system in the middle of the brain.) Afterwards H.M.
was left with severe anterograde amnesia. I.e. He could remember what happened to
him in his life up to when he had the operation but he couldn’t remember anything
new. So now we know the hippocampus is involved in memory

14. ■ 2. Electroencrphalograms (EEGs)
■ This is a way of recording the electrical activity of the brain (It doesn’t hurt and it isn’t
dangerous!). Electrodes are attached to the scalp and brain waves can be traced. EEGs
have been used to study sleep and it has been found that during a typical night’s sleep,
we go through a series of stages marked by different patterns of brain wave.
■ One of these stages is known as REM sleep (Rapid Eye Movement sleep). During this
our brain waves begin to resemble those of our waking state (though we are still fast
asleep) and it seems that this is when we dream (whether we remember it or not).

15. ■ 3. Brain Scans
■ More recently methods of studying the brain have been developed using various types
of scanning equipment hooked up to powerful computers.The CAT scan
(Computerised AxialTomography) is a moving X-ray beam which takes “pictures” from
different angles around the head and can be used to build up a 3-dimensional image of
which areas of the brain are damaged.
■ Even more sophisticated is the PET scan (Positron EmissionTomography) which uses a
radioactive marker as a way of studying the brain at work.The procedure is based on
the principle that the brain requires energy to function and that the regions more
involved in the performance of a task will use up more energy.What the scan therefore
enables researchers to do is to provide ongoing pictures of the brain as it engages in a
mental activity.
■ These (and other) methods for producing images of brain structure and functioning
have been extensively used to study language and PET scans in particular are
producing evidence that suggests that theWernicke-Gerschwind model may not after
all be the answer to the question of how language is possible.

16. Key Features Methodology
•Natural Selection / Evolution
•Adaptation
•Heredity / Genetics
•Nomothetic (studies the group)
•Reductionist
•Instincts / Sociobiology
•Comparative Psychology
•Lab Experiments
•Correlation
•Twin research
•Naturalistic observations (Kettlewell)
•Ethical Considerations
•Reliability and validity of research
Basic Assumptions Areas of Application
•Psychology should be seen as a science, to
be studied in a scientific manner (usually in
a laboratory).
•Behavior can be largely explained in terms
of biology (e.g. genes/hormones).
•Human genes have evolved over millions
of years to adapt behavior to the
environment. Therefore, most behavior will
have an adaptive / evolutionary purpose.
•Gender Role Development
•Abnormal Psychology
•IQ
•Relationships
•Medical Model
•Stress Response (SRRS,stress immune
system)

17. Strengths Limitations
•Very Scientific
•Highly application to other
areas: Biology + Cog =
Evolutionary Psy
•Helped develop comparative
psychology
•Strong counter argument to
the nurture side of the debate
•Many empirical studies to
support theories
•Experiments – Low Ecological
Validity
•Humanism: too deterministic –
little room for free-will
•Doesn’t recognize cognitive
processes
•Reductionist
•Bio psychological theories
often over-simplify the huge
complexity of physical systems
and their interaction with the
environment.

18. ■ Key assumptions of the biological approach:
■ The brain and the mind are identical
■ Biochemical imbalances can affect behaviour
■ Brain physiology can affect behaviour
■ Behaviour can be inherited (as it is determined by genetic information)
■ Evolution and the genetic basis of behaviour
■ Charles Darwin’s publication – On the Origin of Species (1859) – described the
process ofnatural selection; characteristics that are not suited to a species’
environment will die out as it struggles to survive, and with time will evolve over
generations so that only adaptivecharacteristics remain in future offspring.
■ Genes are the genetic information carried by DNA in chromosomes, found within a
cell’s nucleus; they are passed on through generations of a species if individuals
survive and successfully reproduce. In line with Darwin’s theory of evolution, it might
also follow that genes form a basis of behaviour, as both behaviour and genes
appear to be heritable. An example might be aggressive behaviour, in light of
obvious survival benefits such as warding off predators and competing for resources.

19. ■ Nature-nurture debate
■ The genotype describes the genetic configuration of an individual, whereas phenotypedescribes
the combined effects of genetic makeup and surrounding environment on behaviour.The nature-
nurture debate highlights a key argument in psychology, over the relative influence of biology and
environment on the characteristics of an individual; an extreme biological approach assumes that
these are determined solely by nature.
■ Effects of brain physiology and neurochemistry
■ Interactions between regions of the brain help to control different functions, which biological
psychologists assume to be significant in determining our actions. For instance, the occipital lobe is
involved heavily in processing sight, along with the frontal lobe, which is thought to be involved in
control and attention.
■ Electrical impulses enable an important means of internal communication that directs our behaviour,
travelling around the brain and to/from the body via the nervous system. Impulses are transmitted
between neurons (nerves) at synapses, junctions whereneurotransmitters are released
that inhibit or excite other neurons to achieve different responses. Neurochemical imbalances in the
brain are often associated with abnormal behaviour – for instance, evidence suggests that imbalances
of dopamine (a neurochemical linked with the brain’s natural ‘pleasure’ system) are associated with
mood disorders such as depression.
■ The endocrine system is a slower-acting communication system that regulates the circulation
of hormones, released by glands into the bloodstream. For example, cortisol and adrenaline are key
hormones that facilitate the fight or flight response, a key evolutionary survival mechanism whereby
the body primes itself for imminent danger (e.g. increasing heart rate, initiating sweating to cool
down, dilation of pupils, sharpened sense of hearing).

20. ■ Research methods used by the biological approach
■ Animal studies – used to investigate biological mechanisms that govern human behaviour, often
where ethical guidelines would not allow human participation. Many species (e.g. rats) are thought to
have a similar biological makeup to humans, such that studies’ conclusions can be generalised to
humans. However, this methodology still raises ethical debate, and some argue that complex human
behaviour cannot be replicated in non-human animals like rats, and thus cannot be investigated.
■ Case studies – can investigate normal behaviour by observing behavioural abnormality alongside
corresponding changes in biology. A very early example is the apparent personality alteration
observed in Phineas Gage (mid 1800s) after a railroad construction accident drastically changed his
physiology by forcing an iron rod through his brain’s frontal lobe.
■ Drug therapy – behaviour can be manipulated by altering an individual’s biochemistry, a research
method that can ultimately lead to developing drug applications to improve health and wellbeing.
Initial phases of research are usually conducted on non-humans.
■ Scans – physiology and activity across the brain can be gauged using various techniques (e.g. MRI,
PET, CAT), helping researchers to identify the functions of specific regions (known as localisation of
cortical function).
■ Twin/family studies are useful for investigating the heritability of behaviour. For instance, research
can investigate the likelihood that both of two twins develop a characteristic, known as a
concordance rate. However, these studies can be time-consuming, due to long delays often required
before follow-up data is collected. It is also difficult finding a large samples of participants for twin
studies.
■ Example: Evidence has suggested that if one identical twin (monozygotic [MZ], with near-identical
genetic information to the other) develops schizophrenia, there is a roughly 48% chance of the other
also developing schizophrenia, whereas this is only about 17% with non-identical twins (dizygotic
[DZ], who share about 50% of their genes). Such findings support that genetics play a significant part
in the disorder.

21. ■ Evaluation of the biological approach
■ Strengths
■ - Scanning research techniques are useful for investigating the functions of the brain:
an organ with obvious involvement in our behaviour that would otherwise be
unobservable.
■ -The approach presents the strong nature viewpoint of the nature-nurture debate.
■ -The experimental methods used (gathering empirical [i.e. observable] evidence)
make this approach very scientific.
■ Weaknesses
■ -The approach is considered reductionist; complex behaviour, thoughts and emotions
are all equally explained by low-level biological mechanisms such as biochemicals and
nerve impulses.
■ - Biology alone has been unable to explain the phenomenon of consciousness.
■ - An extreme biological approach does not account for the wide base of evidence that
points to the influence of our environment (e.g. culture and society).

22. Nature vs nurture
■ http://www.simplypsychology.org/naturevsnurture.html

23. ■ Nature
■ Physiological/Biological. Psychologists taking this approach believe that behaviour can be explained
via innate influences such as hormones and genetic influences
■ Psychoanalysis - Psychologists taking this approach believe that behaviour is controlled by the innate
aggression and sex drives.They do recognise that society restricts these drives and that these drives
are controlled via the ego and the supergo
■ Nurture
■ Behaviourism - Behaviourists believe that human behaviour is learnt
■ Humanism -This area of psychology explores the impact of a wide range of social and environmental
influences on human behaviour.
■ Developmental - Psychologists looking at development have explored many developmental factors,
such as child rearing practices and the influence of role models, all of which have shaped human
behaviour.
■ Social - Social psychologists have identified the profound influence of other people and social
phenomena such as conformity and group behaviour on our behaviour.
■ An Interaction between Nature and Nurture
■ Cognitive - Cognitive psychology looks at innate cognitive abilities, but recognises that experience
shapes these abilities.

24. Ethological theory

27. NEUROSCIENCE