1 Subjective experience. Corah and Boffa (1970) examined the relationship
between the controllability of the stressor and the subjective experience of stress.
Subjects were exposed to a loud noise (the experimental stressor) and were either
told about the noise (the stressor was predictable) or not (an unpredictable stressor).
The results indicated that if the noise was predictable, there was a decrease in
subjective experiences of stress. The author argued that the predictability enables
the subject to feel that they have control over the stressor, and that this perceived
control reduces the stress response. Baum et al. (1981) further suggested that if a
stressor is predicted there is a decrease in the stress response, and reported that
predictability or an expectation of the stress, enables the individual to prepare their
coping strategies.
2 Physiological changes. Research has also examined the effect of control on
the physiological response to stress. For example, Meyer et al. (1985) reported
that if a stressor is regarded as uncontrollable the release of corticosteroids is
increased.
Does control affect health?
If control influences the stress response, does control also influence the effect of stress on
health and illness? This question has been examined by looking at both animal and
human models.
Animal research
Seligman and Visintainer (1985) reported the results of a study whereby rats were
injected with live tumour cells and exposed to either controllable or uncontrollable
shocks. The results indicated that the uncontrollable shocks resulted in promotion of the
tumour growth. This suggests that controllability may influence the stress response,
which may then promote illness. In a further study, the relationship between control
and coronary heart disease was studied in monkeys (Manuk et al. 1986). Some breeds
of monkey exist in social hierarchies with clearly delineated roles. The monkeys are
categorized as either dominant or submissive. Usually this hierarchy is stable. However,
the authors introduced new members to the groups to create an unstable environment.
They argued that the dominant monkeys show higher rates of coronary heart disease in
the unstable condition than the dominant monkeys in the stable condition, or the sub-
missive monkeys in the stable condition. It is suggested that the dominant monkeys have
high expectations of control, and are used to experiencing high levels of control. How-
ever, in the unstable condition, there is a conflict between their expectations of control
and the reality, which the authors argued results in an increase in coronary heart
disease. These animal models are obviously problematic in that many assumptions are
made about the similarities between the animals’ experience of control and that of
humans. However, the results indicate an association between control and health in the
predicted direction.
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