Psychology Notes for AS & A2

AQA Specification A

Module 2

Physiological  Psychology - Stress as a bodily Response

Human Function Curve

The Human Function Curve

The Human Function Curve shows the effect of stress on our performance.  As Stress and Performance show a strong positive correlation until about 80% stress, where performance drops fast, "crashing" back to zero.

Although stress may be beneficial in the short term, an accumulation of stress is harmful physiologically and psychologically.  A little stress may be good but a lot is bad for us. Stress is a big problem in life today: it is the number one cause of illness and absence from work. Nine out of ten businesses suffer financially, due to loss of production, because of stress.


Cox developed three models of stress, or three ways to understand stress.

  1. Engineering Model
    This takes on the way an engineer looks at things. E.g. when they design a house, they understand the amount of stress it would take for the roof to collapse.  We can think of stress in the same way: something that puts stress on us, or happens to us.  We can work under stress and pressure put upon us can make us better, but can also break us.
  2. Physiological Model
    What stress does to your body, the biology of stress. The physical changes that take place and what happens to us.
  3. Transactional Model
    What is our interpretation of stress? This model says stress happens when there is a miss-match between your perception of the demands being made upon you and your perception of your resources and ability to cope. If you think that something is too much for your, you will be stressed by it, and vice versa.

Definition of stress

Non-specific response of the body to any perceived threat. Illness, heat, cold, fear, injury are all perceived as threats to the body.

Hans Seyle

"Mr Stress", Sely has done more research on stress than everyone else put together. He has had 1500 articles published on the subject, and 32 books.

Seyle was Canadian, trained as a medical doctor. Noticed that all patients in his hospital were sick, regardless of reasons for admission (injury, surgery, illness). He persistently asked his senior doctor why this was so, and eventually got the reply "I don't know Hans, why don't you go and find out?".

Hans spent the next 40 years experimenting firstly with rats, then other animals. He exposed them to various things: disease, cancer, extremes of heat and cold, exhaustion, fear and even surgical injury. He then killed them and cut them open. 

He found that all the animals, in addition to their various problems, had enlarged adrenal glands. Why would the body react in this same way to a variety of stimuli? Stress. Seyle was the first person to describe this syndrome.

General Adaption Syndrome (GAS)

  1. Alarm
    When body recognises there is a danger and prepares to deal with threat. Fight or Flight response, instant.
    • Heart Rate increases (Adrenaline) – to get oxygen to muscles
    • Blood Vessels near to skin shut down, cold and clammy to the touch – injuries won't bleed as readily, blood diverted to important organs
    • Hydrochloric Acid dumped in stomach, digestion shuts down to large extent – acid will dissolve food quicker (easier to run on empty stomach), digesting food diverts precious energy that may be needed elsewhere
    • Incontinence – easier to run, the smell may cause the pursuer to pause for a few precious moments
    • Steroids (Cortisone) fed into bloodstream – to fight infection and inflammation
  2. Resistance (previously called adaption)
    Body adapts or becomes resistant to the stress, starts to function as if this was
  3. Exhaustion
    All reserves are exhausted (crash), body has nothing more to give, things start to go
    wrong and health starts to suffer. You start to become ill, which causes more stress,
    so this stage is a fast drop. See "Human Function Curve".

Long and Short Term physiological problems caused by stress

Short Term

Long Term

High Blood Pressure – caused by increase in heart beat or increase in cholesterol.  Damages blood vessels, the delicate ones burst in the brain and kidneys.
25% of harmful cholesterol in the body comes from foods, which means:
75% or harmful cholesterol in the body is made as a direct result of stress hormones.
Digestive Related Problems – Short Term: Constipation, Diorreah.  Long Term: Irritable Bowel Syndrome, Spastic Colon.

Low Immune System – Short Term: more likely to pick up any bugs going around.  Long Term: reduced ability to fight disease such as cancer.

Sweeney 1995 – wounds heal more slowly on people under stress.

Headaches Strokes
Sleep Disturbance Diabetes (fluctuations of adrenaline / Insulin)
Skin Rashes Ulcers
Teeth Grinding Heart Disease
Over / Under Eating Suicidal Behaviour
Forgetfulness Alcoholism
Aggression & Frustration Domestic Violence
Increased use of alcohol / cigarettes Substance Abuse
Depression Serious Depression

It is estimated that 50 – 90% of hospital beds could be emptied if we eliminate stress. The 50% directly due to stress related illness, the 90 % due to secondary problems: e.g. a stressed driver injures a pedestrian who has to go to hospital.

Measuring Stress

Tests may be self-assessment or biological / physical:

SSRS (Social Readjustment Rating Scale

Changes cause stress – the bigger the change, the more stress induced. Hospital patients were interviewed about events in their lives the previous year, the events were then given a score. If the score exceeds 300 for the last 12 months there was a significant increase in the likelihood of serious health problems.

But – different people react in different ways to stress. Divorce may score 50 to one, and 80 to another, depending on circumstances.

Lazarus – Hassles and Uplifts Scale

Each item is scored as a hassle (negative score) and an uplift (positive score). E.g. my dog may be scored as +5 for the love and companionship he gives, but also scored as –2 for the hassle of having to walk him when it is inconvenient to me. Then the scores are totalled: a negative score indicates a stressful day, and positive score indicates a relatively low stress day. Scores are done daily over a period of time so that persistent hassles can be identified and dealt with.

Biological / Physical Tests

These may take the form of blood test or saliva tests (the very act of taking blood may cause

All Material Copyright 2001 / 2002 Kerridwen Red