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For most adults, work is one of the largest and most persistent sources of stress in their lives. The workplace is therefore a crucial setting for understanding chronic stress and its effects on health, and it has the practical advantage that the stressors involved — workload, deadlines, lack of control, conflict — can be studied systematically and, in principle, changed. This lesson examines two key workplace stressors named by the specification, workload and job control (lack of control), and the influential research that established their effects on health: Johansson et al.'s (1978) study of Swedish sawmill workers and the landmark Whitehall studies of British civil servants (Marmot et al., 1991, 1997). It also introduces Karasek's job demand–control(–support) model, which integrates these factors into a single theory.
Key Definition: Workplace stress is the stress experienced as a result of one's job or working environment. Two of its most important sources are workload (the quantity, pace, and difficulty of work demanded) and lack of job control (the extent to which a worker can influence how, when, and at what pace their work is done).
A central and somewhat surprising finding of this research is that it is often not the most senior, high-pressure jobs that are the most damaging to health, but rather lower-status jobs characterised by low control — a discovery that overturned the popular idea of the stressed-out executive and reshaped occupational health policy.
This lesson addresses the following points in AQA A-Level Psychology (7182), Paper 3, Section C (Stress):
Assessment objectives engaged: AO1 (knowledge of workload and job control as workplace stressors, the Whitehall studies, Johansson et al., and the demand–control model), AO3 (evaluation of the research — its real-world validity, the correlational nature of the evidence, the role of individual differences, and the implications for the workplace), and — where a question contains a scenario — AO2 (applying the concepts to a described worker).
Workload refers to the amount, pace, and difficulty of the work a person is required to do. Both overload (too much work, too fast, too difficult) and, less obviously, underload (monotonous, repetitive, under-stimulating work) can be stressful. High workload activates the stress response chronically: a worker facing relentless demands experiences sustained sympathetic and HPA-axis activation, with the persistently raised cortisol that, as earlier lessons showed, damages the immune and cardiovascular systems over time.
Two distinctions help clarify what "workload" really means as a stressor:
Related workplace stressors that often accompany workload include role ambiguity (uncertainty about what is expected of you), role conflict (incompatible demands), and a poor physical environment (noise, heat). These can amplify the effects of workload, though the specification's focus is on workload and control specifically.
The classic study of workload (and the related stressors of repetition and machine-pacing) was conducted by Johansson, Aronsson, and Lindström (1978), who compared a high-stress and a low-stress group of workers in a Swedish sawmill.
A particular strength of this study is its use of objective physiological measures (urinary stress hormones) in a real workplace, giving it both scientific rigour and high ecological validity. It also begins to disentangle the stressors: the finishers' jobs combined workload with lack of control and isolation, foreshadowing the later focus on control. A further point of real-world significance is that the study's logic supports practical job redesign: because the stress arose largely from machine-pacing and isolation, interventions that give such workers more control over their pace and more social contact would be predicted to lower their stress-hormone output and illness rates — exactly the kind of evidence-based change that occupational health psychology recommends.
One important interpretive note is that the finishers' jobs confounded several stressors at once — high workload, machine-paced loss of control, isolation, and high responsibility — so the study cannot tell us which of these was most responsible for the raised stress hormones. This is precisely the question the Whitehall studies went on to address by isolating control.
If workload were the whole story, we would expect the most senior, demanding jobs to be the most damaging to health. The Whitehall studies of British civil servants, led by Michael Marmot, produced the opposite and far more influential finding.
The Whitehall studies are among the most important pieces of research in health psychology because of their scale, their prospective design (control was measured before disease developed), and their careful control of confounding variables, all of which strengthen the inference that low control contributes to ill health rather than merely being correlated with it.
Key Definition: Job control is the degree of authority and discretion a worker has over their own tasks — how, when, and at what pace they work, and how decisions affecting their work are made. Low job control means the worker has little say over these matters.
It may seem paradoxical that low control is more harmful than high demand, but the explanation lies in two well-established psychological principles: predictability and controllability. A great deal of research, in both animals and humans, shows that the same aversive event is far less stressful if the organism can predict it or exert some control over it. A worker who can decide when to take a break, how to sequence tasks, or how to solve a problem can match their coping efforts to the demands; a worker who is told exactly what to do, when, and how — with no discretion — cannot, and so experiences the demands as uncontrollable and unpredictable. Uncontrollable stressors produce stronger and more prolonged HPA-axis activation, which is the physiological route to the cardiovascular damage seen in Whitehall.
This connects to Seligman's concept of learned helplessness: when individuals repeatedly experience situations in which their actions have no effect on outcomes, they develop a passive, helpless state associated with chronic stress and, in humans, with depression. A low-control job is, in effect, a chronic exposure to uncontrollability. This is also why increasing worker autonomy is such an effective intervention — it restores the sense of control that buffers the stress response, and it explains why the "active" high-demand/high-control job is far healthier than the "high-strain" high-demand/low-control job.
The findings on workload and control were integrated by Robert Karasek into the job demand–control model (later extended to the demand–control–support model). The model proposes that workplace strain depends on the combination of two dimensions:
The crucial prediction is that the most damaging jobs are not simply those with the highest demands, but those that combine high demands with low control — so-called "high-strain" jobs. A job with high demands but also high control (an "active" job, such as a surgeon or senior manager) is far less harmful, because the worker can deploy their autonomy to meet the demands. The matrix below summarises the model.
| High control | Low control | |
|---|---|---|
| High demands | Active job — challenging but manageable; relatively low strain | High-strain job — most damaging to health |
| Low demands | Low-strain job — least stressful | Passive job — under-stimulating, some risk |
The later addition of social support as a third dimension reflects the finding that support from colleagues and managers buffers the harmful effects of high-strain work. The demand–control(–support) model elegantly explains the Whitehall findings: lower-grade civil servants typically occupy high-strain positions (told what to do, with little say over how), which is why their health suffers most, whereas senior staff in active jobs are partly protected by their high control despite heavy demands.
The model makes clear, testable predictions that have proved broadly accurate. It predicts, for example, that a worker in a high-strain job (a call-centre operator with rigid scripts and targets but no discretion) should show worse health than a worker with equally heavy demands but high autonomy (a senior consultant), and that providing the high-strain worker with strong colleague and managerial support should reduce their strain even if their demands and control are unchanged. Predictions of this kind have made the demand–control–support model one of the most influential frameworks in occupational health, informing both research and the design of healthier jobs. It also dovetails with the rest of the Stress option: its "control" dimension links to the hardy personality's sense of control, and its "support" dimension anticipates the buffering effects of social support studied later.
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