Summary
Summary AQA A-Level Psychology - Stress Revision Notes
Comprehensive set of revision notes for AQA A-Level Psychology - Stress. Achieved an A* and secured a place at the University of Oxford. Based off of the AQA syllabus.
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The physiology of stressThe General Adaptation Syndrome (GAS)
Selye believed that the process of adapting to a stressor goes through three stages:
Alarm reaction - once a stressor is perceived, the physiological responses of the body are activated
in preparation for fight or flight.
Resistance - the body attempts the adapt to the stressful environmental demands by resisting the
stressor. The individual appears to be coping but the body's resources are being consumed at a
potentially harmful rate; for instance, stress hormones are produced in huge quantities and it is only
a matter of time before they cause damage to the heart and blood vessels. The parasympathetic
nervous system s activated to conserve energy for the longer term, because the stressor is becoming
chronic.
Exhaustion - adaption to a chronic stressor is now failing. The resources needed to resist have
become drained, and so the individual begins to re-experience the symptoms of sympathetic arousal
that first appeared in the alarm stage (e.g. raised heart rate and blood pressure). The adrenal glands
may become damaged and the immune system compromised. Stress-related illnesses are now likely.
Evaluation
Research evidence - Selye supported his model with research. He initially experimented with
rats, subjecting them to various stressors including extreme cold, excessive exercise and injury.
He found that the same typical collection of responses occurred regardless of the stressor. Selye
was then able to track the rats' response to a continuing stressor through the resistance and
exhaustion stages, providing the evidence for GAS. This shows that the body's general response
to a stressor is a physiological reality, at least in rats.
Key to the GAS is the idea that the stress response is non-specific, that it is the same regardless
of the stressor. However, when Mason replicated Selye's procedures using monkeys instead of
rats, he found that different stressors produced different changes in cortisol levels; extreme
cold increased cortisol levels, extreme heat reduced them, and excessive exercise produced no
changes. This therefore challenges a central concept of Selye's theory by showing that specific
stressors can produce specific responses.
The physiological response
Acute stress
When a threat is perceived, the sympathetic branch of the autonomic nervous system (ANS) is
activated by the hypothalamus.
Sympathetic arousal stimulates the adrenal medulla to release the hormones adrenaline and
nonadrenaline into the bloodstream.
These hormones cause the heart to beat faster, muscles to tense and the liver to convert stored
glycogen into glucose which is released into the bloodstream to provide energy to fuel the fight
or flight response.
, Once the stressor is no longer a threat, the parasympathetic branch is activated and arousal
decreases. The priority now is for energy conservation rather than expenditure.
Chronic stress
The body's response to long-term stress is activated by the HPA system.
When the hypothalamus is activated because of a stressor, not only is the sympathetic branch of
the ANS activated, but a hormone called CRF is also produced.
This hormone is detected by the anterior lobe of the pituitary gland, causing the release of
ACTH into the bloodstream.
ACTH stimulates the adrenal cortex to secrete the hormone cortisol.
The HPA is self-regulating via a negative feedback loop; high levels of cortisol trigger a reduction in
both CRF and ACTH, resulting in a corresponding reduction in cortisol.
Evaluation
Male bias in biological research - there were dangers for our evolutionary female ancestors in a
stress response geared towards fight or flight. If a female responds in this way, her children are
at risk because it leaves them vulnerable. Therefore, some psychologists argue that the fight or
flight response is characteristic of males, whilst the tend and befriend response is more adaptive
in females. The assumption that fight or flight is valid in all humans is a reflection of bias towards
male physiology.
Psychological factors are ignored - Lazarus argues that we make appraisals of a stressor by
actively working out if it is a threat (primary appraisal) and whether we have the resources to
cope with it (secondary appraisal). With this in mind, it became evident through a study where a
group of students had their heart rate monitored whilst they were watching a gruesome medical
procedure on film, that it is ones interpretation of an event that determines the response. If they
believed the procedure to be traumatic, their heart rate went up, but if they perceived it to be
the process of saving one's life, then their heart rate actually went down.
The role of stress in illness
Immunosuppression
Stress can suppress the immune system directly, through the production of cortisol which inhibits
the production of lymphocytes.
Stress can also have indirect immunosuppressive effects too, as it can influence lifestyle behaviours
(e.g. smoking, drinking, sleep patterns), that in turn have a detrimental effect on immune
functioning.
Kiecolt-Glaser investigated the effects of preparing for exams:
75 medical students gave blood samples twice, one month before an exam (low stress) and on
the day of the first exam (high stress). They also completed questionnaires measuring sources of
stress and self-reported psychological symptoms.
It was found that levels of NK and killer T cells decreased between the first and second samples,
which is evidence of an immune response being suppressed by a common stressor.
, This decline was most apparent in students who reported feeling most lonely and in those also
experiencing other sources of stress.
Cardiovascular disorders (CVDs)
There is evidence that stress may contribute to the development of various cardiovascular disorders
such as heart disease and strokes. It appears that stress can have both immediate (acute) and longer
term (chronic) effects on CVDs.
Acute stress
Wilbert-Lampen et al. looked at incidences of heart attacks during football matches played in
Germany during the 1996 World Cup.
On the days when Germany played, cardiac emergencies increased by 2.66 times compared with
a control period.
It appears that the acute emotional stress of watching your favourite football team can more
than double your risk of suffering a cardiovascular event.
Chronic stress
Yusuf et al. compared 15,000 people who had had a heart attack, with a similar number of
people who had not.
They found several chronic stressors with a strong link to heart attacks, including workplace
stress and stressful life events.
In fact, the contribution of stress to heart attacks was greater than obesity, and third only to
smoking and cholesterol levels.
Evaluation
Acute stress can actually benefit immunity - Dharbhar subjected rats to mild stressors and
found that this was enough to stimulate a substantial immune response; immune cells such as
lymphocytes flooded into the bloodstream in preparation for physical damage. So whilst chronic
stressors are dangerous because of their immunosuppressive effects, this research shows that
acute stressors can stimulate the immune system. Clearly then, the relationship between stress,
the immune system and illness is not as clear cut as once thought.
Immunosuppression and cancer - there is support for the immunosuppressive effects of stress
being linked to certain cancers. Pereira et al. studied women who were HIV-positive, and found
that those who experienced many stressful events were more likely, one year later, to develop
pre-cancerous lesions of the cervix than those who experienced fewer stressful events.
Causing CVDs versus causing heart attacks - it has been proposed that stressors may cause
heart attacks in those that already have CVDs, rather than stressors causing CVDs themselves.
Orth-Gomer et al. found that in women with CVDs, that marital conflict created stress that
tripled the risk of heart attack. This is a different proposition to that which says stress causes
CVDs to develop in the first place.
Sources of stress: life changes
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