In psychology the theory of evolution has been used to explain how the human mind and behaviour have
changed over millions of years so that they are adapted to the demands of our individual environments
Theory of natural selection
based on Darwin’s theory of natural selection, this is the idea that any genetically determined
behaviour that enhances an individual’s chance of survival and reproduction will be naturally selected
Natural selection takes place at the level of genes. An
example of this is altruistic behaviour where parents risk
their life to save their offspring.
The theory of natural selection says that altruism is an
inherited adaptive trait because saving an offspring or
relative enhances the survival of the gene pool.
Environment of evolutionary
adaptiveness (EEA)
This is the environment to which any species is adapted
and the selective pressures that existed at that time.
Evolutionary psychologists don’t assume all forms of behaviour are adaptive – only the ones that will
ensure the survival in that individual’s particular environment.
genes for survival behaviours are the ones that are passed on
most recent period of evolutionary change
was about 2 million years ago when humans
moved from forest life to savannahs in Africa
A theory on human brain size would propose that the brain has evolved
in response to the complex social organisation of our species. Those
humans with particular abilities would be more likely to survive
assumption 2: localisation of brain function
certain areas of the brain are responsible for different
functions – they have certain jobs or tasks to carry out
The cerebral cortex covers the brain and is the area of the
brain responsible for higher order cognitive functions
Four Lobes:The cerebral cortex is divided into four regions: frontal, parietal,
temporal and occipital. Each of the four regions or ‘lobes’ has specific functions.
The frontal lobes are involved in thinking and creativity and have been linked to our personality.
The parietal lobes receive sensory information such as temperature, touch and pain
The temporal lobes are responsible for much of our memory
processing as well and the processing of auditory information
The occipital lobes are concerned with visual processing
and receive information directly from the eyes
localisation of language
French neurosurgery Paul Broca studied 8 patients with language problems. in the mid 19th century
examined their brains after death and found that they had damage to a specific area of their left hemispheres.
This area was named
Broca’s area (posterior
portion of the frontal
lobe) and is associated
with speech production
There are specific areas of the brain linked
to the processing of language.
Carl Wernicke, German neurologist, discovered another area of the brain involved in understanding language.
named Wernicke’s area it is in the posterior portion of the left temporal lobe. His patients could speak but were unable to understand language
Assumption 3: neurotransmitters
Neurons are electrically excitable cells that form the basis of the nervous system.
The flexibility of the nervous system is enhanced by having many branches as the end
of each neuron (called dendrites) so that each neuron connects with many others.
neurons communicate with each other
at a synapse, where the message is
relayed by chemical messengers
neurotransmitters are released from presynaptic vesicles and will either stimulate receptors in the
other neuron. The synaptic cleft or gap is about 20nm wide
Neurotransmitters have been found to play a significant role in our mental health.
Too little serotonin has been found in people suffering from depression. Some antidepressant
medication therefore works by increasing the availability of serotonin at the postsynaptic receptor sites
High levels of the neurotransmitter dopamine have been associated with symptoms of schizophrenia. This is supported by the fact that drugs
that block dopamine activity reduce schizophrenia symptoms.
relationship formation
Evolutionary theory proposes that relationships form with individuals who possess certain traits.
Traits that enhance successful reproduction are naturally selected
males and females experience different
selective pressures.
Females also seek signs of fertility and healthiness in their partner, but are more concerned to find a partner who
can provide he resources needed for offspring to survive
Males so well to mate as frequently as they can and select women who are more fertile and healthier
parental investment theory (Trivers, 1972): According to parental investment theory, as female mammals invest more in their offspring
(e.g. they carry the baby), they must be ‘choosier’ in finding a partner and hence will seek out the male that can provide the most.
The chemicals in out brain have powerful effects on our emotions, and in turn will influence our
perceptions of others including those we may enter relationships with.
Dopamine has been associated with pleasure seeking and reward driven behaviour, so setting the
goal of finding a partner and being driven to achieve this will give us a hit of dopamine
This can explain why we are driven to form
relationships as humans as it gives us a natural high.
Oxytocin is a hormone linked to human bonding and increasing trust and loyalty,
and high levels of oxytocin have been linked to romantic attachment
it is thought that a lack of physical contact with one’s partner will reduce levels
of oxytocin, leading to feelings of longing to bond with ones partner again
acts as another explaination for relationship formation as we have a
natural chemical drive to bind with others.
Evolutionary theory can also explain the close
relationship often found between brothers and sisters
there is also kin selection – traits that enhance the survival of those who have
similar genes are also selected to promote the survival of our group’s gens
we have a natural incentive to look after our siblings, and to invest time, energy and other resources
into ensuring they are protected and healthy
therapy:drug therapy
The approach to therapy is known as the medical model ; it has the view that
mental illnesses are like physical illnesses and that a patient should treat their
mental health through direct manipulation of their psychical bodies’ processes
A econd assumption is that the brain’s neurotransmitter systems will affect our
mood, feelings, perception and behaviour; suggested psychotherapeutic drugs
can be used to alter the actions for neurotransmitters and treat medical disorder
A third assumption is that drugs target specific
regions of the brain (localisation of brain functions)
which are involved in psychological disorder
drug therapy operates by increasing or blocking
the action of neurotransmitters in the brain to
influence our emotions, thoughts and actions.
The three main types of psychoactive drugs are antipsychotics; antidepressants and antianxiety drugs.
antipsychotics
Treat psychotic mental disorders such as schizophrenia.
Conventional antipsychotics are used primarily to combat the positive symptoms of schizophrenia
(e.g. delusions and hallucination)
These drugs block the action of the neurotransmitter dopamine in the brain by
binding to but not stimulating dopamine receptors.
The atypical antipsychotic (i.e. Clozaril) act by only temporarily occupying dopamine receptors, and
then rapidly dissociating to allow normal dopamine transmission
This may explain why such atypical antipsychotics have lower levels of side
effects compared with conventional antipsychotics.
A patient with a psychotic mental disorder has lost touch
with reality and has little insight into his or her condition
antidepressants
Depression is thought to be due to insufficient
amounts if neurotransmitters such as serotonin
being produced in the nerve endings
To terminate their action, neurotransmitters are reabsorbed into the nerve endings and are broken down by an enzyme.
Antidepressants work either by reducing the rate of reabsorption, or by blocking the enzyme that breaks down the neurotransmitters.
Both of these mechanisms increase the
amount of neurotransmitters available
to excite neighbouring cells.
The most commonly prescribed antidepressant drugs are selective serotonin reuptake inhibitors (SSRIs) such as Prozac.
These work by blocking the transporter mechanism that reabsorbs serotonin into the presynaptic cell after it has fired.
As a result, more serotonin is left in the synapse, prolonging its activity and making transmission to
the next impulse easier.
anti anxiety
The group of drugs most commonly
used to treat anxiety and stress are
benzodiazepines (BZs).
They are sold under
various trade names such
as Librium and Valium.
BZs slow down the activity of the central nervous system. They
do this by enhancing the activity of GABA, a biochemical
substance that is the body’s natural anxiety relief.
Beta-Blockers (BBs) are also used to reduce anxiety.
They reduce the activity of adrenaline and
noradrenaline, which are part of the response to stress.
BBs bind to receptors on the cells of the
heart and other parts of the body which are
stimulated during sympathetic arousal.
By blocking these receptors, it is harder to stimulate cells in this part of the body, so the heart beats slower
and with less force, and blood vessels do not contact so easily
This results in a fall in blood pressure, and therefore less stress on the heart leaving the person
feeling calmer and less anxious
effectiveness
drugs versus placebo
There is considerable evidence for the effectiveness of drug
treatments. Typically, a randomised control trial is used to
compare the effectiveness of the drug versus a placebo.
Soomro et al 2008 reviewed 17 studies of the use of SSRIs
with OCD patients and found them to be more effective than
placebos in reducing symptoms of OCD up to 3 months after
treatment (in the short term).
Kahn et al 1986 followed 250 patients
over 8 weeks and found BZs to be
significantly superior to placebos.
However, one of the issues regarding evaluation of
treatment is that they only normally last 3-4 months and
so there is only a small amount of long-term data, Koran
et al 2007 criticised the short-term data.
side effects
While drugs are generally effective in treating
psychological disorders, many have serious side effects.
For example: nausea, headaches and insomnia are common side effects
of SSRIs (Soomro et al 2008). These may not seems terrible but are
often reasons for people not to take the drug.
Tricyclic antidepressants tend to have more side effects- hallucinations
and irregular heartbeat are common- than SSRIs so they are more likely to
be used in cases where SSRIs were not effective.
symptoms not cause
drug therapy is that whilst drugs may be effective in treating symptoms of psychological disorders,
this type of therapy does not address the underlying cause.
This will lead to what is known as the ‘revolving door syndrome’ where a patient is back and forth to
their doctor as they are never really cured
comparison with other
treatments
Relative to other treatments (e.g. psychotherapy) drug therapy is cheap for
the patient – in the UK they would be prescribed their drugs on the NHS.
The practitioner has to invest less time on the patient because they only need
to meet with the patient every couple of months after the initial consultation.
Therefore, this type of therapy is effective and easy to
administer compared to other forms of therapy.
ethical issues
use of placebos
a fundamental research ethic is that no patient
should be given a treatment known to be inferior
If effective treatments exist, they should be used as the
control condition when new treatments are tested.
Substituting a placebo for an effective treatment does not satisfy this
duty as it exposes individuals to a treatment known to be inferior.
patient information
Another ethical problem is the issues of valid consent or lack of it.
Many patients will find it difficult to remember all the facts relating to potential side effects of the
drug prescribed or they simply may not be in a frame of mind to digest this information
Therefore, valid consent is seen as an
illusion.
Furthermore, medical professionals may withhold some information about the drugs and for
example may not explain the pharmacological benefits of the drug are slim.
Some medical professionals may also exaggerate the benefits of taking medication and may fail to
inform the patient of the other therapeutic options due to the ‘quick fix’ nature of drug therapy.
Raine, Buchsbaum and LaCasse 1997
Early therapies suggested that there might be a physical difference between
criminals (C) and non-criminals (NC).
This would enable us to identify individuals before they committed a crime.
Cesare Lombroso 1876 suggested that criminals typically had a narrow, sloping forehead,
prominent eye ridges, large ears and a protruding chin.
brain scanning techniques opened a new way to research to
research the differences between C and NC
it was thought that regions of the brain were responsible for C; animal research and studies of people
with brain damage gave clus to which regions to look at.
they focused on one particular group of C's – people who had committed a murder and entered a plea
of not guilty by reason of insanity (NGRI)
The researchers proposed, on the basis of
previous research that seriously violent
individuals:
- Would have brain dysfunction in the: prefrontal cortex, angular gyrus, amygdala, hippocampus,
thalamus and corpus callosum
- Would not have brain dysfunction in the areas of the brain that have been implicated in mental illnesses
but not previously related to violence: caudate, putamen, globus pallidus, midbrain, cerebellum
methodology
This was a quasi-experiment with match pair designs. The IV is NGRI or not, the DV is brain differences.
Murders (experimental group):
41 murderers, 39 men 2 women
average age of 34.3 years
all been charged with murder or manslaughter and all of them pleaded NGRI or incompetence to stand trial
referred to the University of California for explanation to obtain proof of their diminished capacity
the murderers had some form of mental impairment
Mental disorder;Number: Schizophrenia;6- History of head injury or organic brain injury;23- History of
psychoactive drug abuse;3- Affective disorder;2- Epilepsy;2- History of hyperactivity and learning
disability;3- Personality disorder;2
participants were instructed to be medication free and were checked with urine scans for 2 weeks prior to brain scanning
Control group
formed by matching each murdered with a normal individual of the same sex and age
The 6 schizophrenics were matched with 6 schizophrenics from a mental hospital
The other controls had no history of psychiatric illness, nor was there a history of psychiatric illness in any close relatives and no significant physical illness
None were taking medication.
procedures
The sample was obtained using opportunity sampling. A PET scan was used to study the active brain.
The article provides precise details of the scanning techniques so that the study could be replicated.
All participants were given an injection of a ‘tracer’
(fluorodeoxyglucose FDG)
This tracer is taken up by active areas of the brain and thus it was
possible to compare the brains of the NGRI and control groups.
they were all asked to do a continuous performance task (CPT) aimed to activate the target areas of the brain so the investigators could see how the different areas functioned.
1. participants were given a chance to practise
the CPT before receiving the FDG injection
2. 30 seconds before the FDG injection participants started the CPT so that the initial task
novelty wouldn’t be FDG labelled.
3. 32 minutes after the FDG injection a PET scan was done with each participant. 10 horizontal slices
(pictures) of their brain were recorded using the cortical peel and box techniques.
findings
The study found reduced activity in the brain of NGRI participants in areas previously linked to violence
- prefrontal cortex
- Left angular gyrus
- Corpus callosum
- In the left hemisphere only there was reduced activity in the amygdala, thalamus and hippocampus
The study found increased activity in the brain of NGRI
participants in areas not previously linked to violence:
- Cerebellum
- In the right hemisphere there was increased activity in the
amygdala, thalamus and hippocampus
The study found no difference between NGRI group and
controls in areas not previously linked to violence:
- Caudate
- Putamen
- Globus pallidus
- Midbrain
summary: murderers had->
- Reduced activity in some areas, notably areas previously linked to violence, eg reduced glucose metabolism
- Abnormal asymmetries – reduced activity on left side of the brain, greater activity on the right.
Applied to some areas identified in the hypothesis as being linked to violence (amygdala, thalamus
and hippocampus)
- No differences in many brain structures, notably structures associated with mental illness but not violence
Both groups performed similarly on the CPT. Therefore any observed brain differences were not related to task performance.
Some differences between the NGRI group and control group noted:
- Handedness: six of the murdered were left handed but in fact they had less amygdala asymmetry and higher medical prefrontal activity than right handed murders
- Ethnicity: 14 of the murderers were non-white but a comparison between them and white
murderers showed no significant difference in brain activity
- Head injury: 23 of the murderers had a history of head injury but they didn’t differ from those
without a head injury
Conclusion
the findings provide preliminary evidence that
murderers pleading NGRI have different brain
functioning to normal individuals.
However, neural processes underlying violence are complex
and can’t be reduced to a single brain mechanism.
Violent behaviour can probably best be explained
by the disruption of a network of interacting brain
mechanisms rather than any single structure
Such disruption would not cause violent behaviour but
would predispose an individual to violent behaviour
Confounding variables:
The study was carefully designed, involving a large sample and matched controls. However, Raine, Buchsbaum and LaCasse acknowledge that head injury and IQ have not been
ruled out as contributary factors.
Warning
1. the results do not show that violent behaviour is determined by biology alone
2. the results do not show that murderers pleading NGRI are not responsible for their actions, nor that
PET can be used as a means of diagnosing violent individuals
3. the results do no show that brain dysfunction causes violence. It may be that brain dysfunction is an
effect of violence
4. the results do not show that violence can be explained by the results, the results relate only to criminal behaviour
Nevertheless the findings do suggest a link between brain dysfunction and a predisposition towards violence in this specific group (NGRI murderers) which should be further investigated.
see table in book for links between areas of the brain and aggression
Continued
Evaluation
A quasi-experiment-
the IV in this study (criminal status) was an existing condition of the
individual, not something that was manipulated by the experimenter
it is a quasi-experiment and casual
conclusions are not justified
the limitation of this method is that
no casual conclusions can be drawn
danger is that readers misinterpret the findings and assume
that criminal behaviour is predetermined and inescapable.
the findings do not show that violent behaviour is determined by biology alone, RBC suggest that psychological, cultural and situational factors play important roles in predisposition to violence.
research techniques
Data was collected in this study using PET scans: allows detailed study of the brain
not possible until recently. In the past, researchers relied on post-mortem examinations
enable the brain in action to be examined
the sample
findings do not show that all violent offenders have such brain dysfunctions
the crime is one of murder and many violent crimes do not involve murder
conclusions are restricted to a very particular group of people
alternative evidence
Adrian Raine continued to conduct research on the association
between criminal behaviour and brain dysfunction
a study by Yang and Raine 2009 was a meta-analysis of 43 imaging studies that
considered both antisocial and violent behaviour.
conclusions was that there is significantly reduced prefrontal activity in
antisocial and/or violent individuals.
genetic studies indicate a ‘criminal gene’. One candidate for this MAOA gene (monoamine oxidase A) that causes
abnormally high levels of the neurotransmitter dopamine.
Tilhonen et al 2015 analysed genes of 895 Finnish prisoners and found an association between this
gene and an increased likelihood of committing a violent crime.
genes are only predisposing factors
neuroscientist , James Fallon, analysed his own genes and found that he had the
genetic and brain characteristics of a violent criminal but wasn’t actually one
suggested that his positive experiences during childhood meant
that his potentially criminal tendencies were not triggered
diathesis-stress explanation (a genetic predisposition which is only
manifested if certain stressors trigger it – i.e. a difficult childhood)
Ethical issues and social implications
Valid consent
main group of participants were murderers who pleaded
NGRI
suggests that they may not have been mentally competent to provide valid
consent
participants may not have fully understood what they would be required to
do.
E.g. they may have found the performance task difficult and potentially lowered their self-esteem – psychological harm
The murderers may have also not understood their right to withdraw at any time
- may have felt forced to see the study through.
socially sensitive research
ethical issues is the broader social implications of this research .
Socially sensitive research refers to any research that has consequences
for the larger group of which participants are members
With research on murderers the question is whether our
understanding of criminal behaviour is advanced by the research
If it indicated murderers are born nor made this would be disadvantageous
for people with similar abnormalities- may be imprisoned without trial
Thus the research findings have
implications for thr prisoners.
Means that important decisions have to be made about the way it is conducted and reported.
Contemporary debate: is neuroscience ethical?
for
understand consciousness
Francis Crick and Christof Koch 1998 propose that the claustrum, a thin sheet of neurons found in
the centre of the brain, is the seat of the consciousness.
54 year old woman support his – she suffered from severe epilepsy and during some tests on her
brain and electrode placed near the claustrum was electrically stimulated.
The women stopped reading, stared blankly and didn’t respond to visual or auditory commands, when the
stimulation stopped, she regained consciousness immediately with no recollection of the event
repeated by Koubeissi et al 2014 who found the same results.
This could help us make decisions about patients who are in a persistent vegetative state and the decision to end their life could be based on their consciousness.
treat criminal behaviour
Cherek et al 2002 investigated the levels of impulsivity and aggression
in males with a history of conduct disorder and criminal behaviour
Half received a placebo for 21 days and the others were
given paroxetine (SSRI antidepressant)
Those who had paroxetine showed a significant decrease in impulsive
responses, and aggressions declined by the end of the study.
Offers pharmacological treatments to criminals could reduce recidivism and make society safer for all.
enhance neurological function
Transcranial Direct Current Stimulation (TDCS) involves passing
a small electric current across specific regions in the brain.
Cohen Kadosh et al 2012 found that TDCS leads to improvements in
problem-solving and mathematical, language, memory and attention capabilities.
Students could use TDCS in
preparation for exams.
Marketing techniques
When interviewed by market researchers we may not give our
true opinions in order to appear better- social desirability
This can be avoided using eye tracking equipment which
provides objective evidence. EEG can also be used.
Sands research used and EEG to produce ‘The Force’ advert for Volkswagen, it upped
traffic on the VW website by half and contributed to the success of the brand.
against
understand consciousness
The implications are unlimited.
Moral question – if someone does not have consciousness
should you be able to kill them (vegetative state).
Questions the soundness of the evidence as it is drawn from a case study of one ‘abnormal’ brain.
treat criminal behaviour
many see criminal behaviour as a response to social factors.
Even if there is a neurological basis there is a question of whether it is acceptable to include mandatory neurological interventions.
Martha Farah 2004 argues that if courts use neurological interventions, it signals the denial of the
individual’s freedom, something not previously denied
Furthermore, a court may offer a convicted criminal the choice of a prison sentence or medication,
introduces an ethical issue of implicit coercion
enhance neurological function
Cohen Kadosh et al 2012 warn of ethical implication to TDCS tech.
No training or licencing rules for practitioners – could lead to poorly qualified clinicians administering treatments, potential brain damage
Although comparatively cheap, TDCS is not available to everyone;not fair to allow some benefit and not all
effects on developing brains.
marketing techniques
Wilson et al 2008 believe commercial integration of neuromarketing
research will allow advertisers to deliver individualised messages where
our free will is potentially manipulated by big brands.
not obliged to abide by
ethical codes of practice
Nelson 2008 found that 5% of brain scans recorded by marketing firms produced incidental findings
such as evidence of brain tumours or problems with brain function. As they are not board certified
they are not obliged to follow ethical protocols such as advising them of the findings.
Evaluation
Scientific approach
Believe that behaviour can be
explained in terms of the brain,
neurotransmitters and
localisation of brain function.
Means that biological explanations have clear
variable to measure, track and examine.
Enables scientific research to be conducted.
E.g. research on drug therapy investigated the links of behaviour and between drugs and production of neurotransmitters
E.g.Raine, Buchsbaum and LaCasse used PET scans which is a form of scientific research
Determinist approach
If we know what predetermines our behaviour then it is easier to treat issues.
E.g. want to understand neurotransmitters so that they can see if someone has issues/ solve issues
Use of scientific research shows that dopamine plays
apart in schizophrenia – determinist because it limits
it to just dopamine effects not the environment etc
Brain scans are used to identify active areas
of the brain – can use this to identify areas
of the brain that are over/under active.
If we can figure out what causes issues in (all) people than we can help to solve issues for (all) people
Successful applications
Given us solutions/ help with mental disorders, allows people to live more
regular lives and ‘fit’ in society
Cherek et al 2002 showed males with conduct disorder and criminal behaviour had
reduced levels of aggression and impulsivity after a 21 day course of an anti-depressant
compared to a control group taking placebos.
Drug therapy had mixed results because drugs affect people differently but it does help
many people with mental health disorders – bipolar disorder has been treated with drugs,
Viguera et al 2000 reported that >60% of bipolar patients improved after taking
lithium
Reductionist approach
Reducing stress to just adrenaline can ignore other causes for e.g. It is part of understanding how
things work but in the process it is easy to lose a real understanding of the thing being investigated.
The approach suggests that schizophrenia is basically a complex physical chemical system that has gone wrong
R.D. Laing 1965 claimed the approach ignored the experience of distress that goes with mental illnesses and is therefore incomplete
Nature over nurture
Only focuses on the nature aspect of mental illness and often ignores life experience and how people think/feel.
Doesn’t look at how people feel about their illness but is just concerned with the abnormal levels of neurotransmitters.
In terms of treatment it doesn’t
look at feelings just body make
up
Individual differences
(nomothetic)
Looks to make generalisations about people and ignored peoples differences.
e.g. when stresses some people produce more adrenaline than others which affects the long-term effects often focuses
on just a few individuals and assumes everyone is the same as them.
Tend to use males more than females because female cycles effect hormones – another difference, male bias
Taylor et al 2000 suggests men usually react to stress with a fight or flight response but women ten to show a tend and befriend response.
This is seen across various species where the female will protect and nurture their young and seek social contact and
support from other females – attributed to the hormone oxytocin which women produce when stressed
there are sevreal strands to the biological approach: physiological approach, nativist approach and medical model
physiological: believes that all behaviour is due to the
functioning of internal body parts i.e. the brain/ hormones
nativist: assumes that all behaviour is inherited and passed
down through our genes from generation to generation
medical model: refers to the treatment of physiological disorders based on the same principles used to treat physical disease;
argument is based on psychological problems being caused by physical things and having a physical treatment (medical)