General Adaptation Syndrome (Selye): WACE Year 12 Psychology Unit 4
“Models of stress: stress as a response, the General Adaptation Syndrome (GAS) model (Selye, 1936, 1983): physiological response to stress (heart rate, breathing rate) and the stages alarm, resistance and exhaustion”
Selye's General Adaptation Syndrome (GAS) treats stress as a response: the body reacts to any prolonged stressor in the same three stages. In alarm, the body detects the stressor and the fight-or-flight response increases heart rate and breathing rate; resistance first dips below normal (shock), then rises (countershock). In resistance, the body adapts and resistance stays above normal while resources are used up. In exhaustion, resources run out, resistance falls below normal and the risk of illness rises.
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What this dot point is asking
The syllabus names three models of stress. GAS is "stress as a response"; the Social Readjustment Rating Scale is "stress as a stimulus"; and the transactional model is "stress as a transaction". You should describe each stage, refer to heart rate and breathing rate, sketch or interpret the GAS graph, and evaluate the model.
Stress as a response
Selye observed that very different stressors produced the same general physical reaction, so he defined stress by the body's response rather than by the stressor or by how a person thinks about it. The GAS describes how that response changes when a stressor continues over time.
The three stages
| Stage | What happens | Heart rate and breathing rate | Resistance to stress |
|---|---|---|---|
| Alarm: shock | The body is caught off guard by the stressor; functioning briefly dips | May briefly drop | Falls below normal |
| Alarm: countershock | The sympathetic nervous system triggers fight-or-flight; stress hormones are released | Increase sharply | Rises above normal |
| Resistance | The body adapts to the continuing stressor; stress hormones such as cortisol keep energy available | Settle but stay above resting levels | Stays above normal, while resources are depleted |
| Exhaustion | Resources are used up and the body can no longer maintain resistance | May become irregular; the person feels fatigued | Falls below normal; vulnerability to illness |
Draw resistance to stress on the y-axis and time on the x-axis, with a dashed line for normal resistance. The curve dips below normal (shock), rises well above it (countershock and resistance), stays high through resistance, then falls below normal in exhaustion.
Why prolonged stress harms health
During resistance, the body is using energy to fight the stressor, and stress hormones such as cortisol suppress the immune system. This leaves fewer resources for other demands, so people in the resistance stage are more likely to catch colds and other infections. In exhaustion, stress-related conditions such as heart disease, high blood pressure, anxiety and depression become more likely.
Strengths and limitations
Strengths.
- One of the first models to show a link between long-term stress and physical illness.
- Describes a measurable physiological pattern (heart rate, breathing rate, hormone levels), supported by later research.
- Applies to many kinds of stressors.
Limitations.
- Treats the response as the same for every stressor and every person; it ignores psychological factors such as how the stressor is appraised.
- Much of Selye's original research was done with rats, so generalising to humans is limited.
- It does not explain why some people are more resilient than others.
A small business owner during a long drought
- Alarm: when the drought is declared and sales fall, the owner feels a jolt of panic (shock), then their heart pounds and breathing speeds up as fight-or-flight kicks in (countershock).
- Resistance: over the following months they work long hours to keep the business going. Their heart rate and breathing settle, but they feel constantly on edge and catch several colds.
- Exhaustion: after a year, they feel drained, cannot sleep properly and develop high blood pressure.
Marker's note: name each stage, link it to the scenario, and refer to heart rate, breathing rate or resistance.
- Saying resistance is below normal for the whole alarm stage
- It dips below normal only during shock, rises above normal in countershock, and stays above normal throughout the resistance stage.
- Leaving out the dip in shock
- Resistance first falls below normal before rising.
- Treating GAS as including thinking
- GAS is a physiological model; cognitive appraisal belongs to the transactional model.
Exam-style questions
Questions in the style of SCSA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
Original6 marksDescribe the three stages of Selye's General Adaptation Syndrome, referring to changes in the body's resistance to stress and to heart rate and breathing rate.Show worked answer →
Two marks for each stage.
- Alarm
- The body first recognises the stressor. In a brief shock phase, resistance drops below normal. In countershock, the sympathetic nervous system activates the fight-or-flight response: stress hormones are released, heart rate and breathing rate increase, and resistance rises above normal.
- Resistance
- If the stressor continues, the body adapts to cope with it. Resistance stays above normal, supported by stress hormones such as cortisol. Heart rate and breathing rate may settle towards normal but stay elevated, and resources are being used up.
- Exhaustion
- If the stressor persists, the body's resources are depleted. Resistance falls below normal, and the person becomes vulnerable to fatigue and stress-related illness.
Original4 marksExplain one strength and one limitation of the General Adaptation Syndrome as a model of stress.Show worked answer →
Two marks for each.
Strength. It was one of the first models to link prolonged stress to physical illness and describes a measurable physiological pattern, which is supported by later research on stress hormones and immune function.
Limitation. It describes stress as the same non-specific response to every stressor and ignores psychological factors: it cannot explain why two people respond differently to the same stressor, which the transactional model explains through cognitive appraisal. Much of Selye's original evidence also came from rats, which limits generalisation to humans.
Practise this
Sources & how we know this
- Psychology ATAR course Year 12 syllabus (effective from 1 January 2024) — School Curriculum and Standards Authority (SCSA)
- Psychology ATAR course: syllabus and support materials — SCSA
- Past ATAR course examinations — SCSA