Social Support and Stress

Individual Differences in Stress: Locus of Control

Locus of control (Rotter, 1966) is a personality construct describing the extent to which individuals believe that outcomes in their lives are determined by their own behaviour and characteristics (internal locus of control) or by external forces such as luck, fate, or powerful others (external locus of control). It has been extensively studied as a moderator of the stress-health relationship, with internal LOC generally associated with more adaptive stress responses and better health outcomes.

Rotter's (1966) Framework

Rotter (1966) developed the Internal-External (I-E) locus of control scale — a forced-choice questionnaire assessing the degree to which individuals attribute outcomes to internal or external causes. High internal LOC: 'Getting a good grade depends on how hard I studied'; 'My health is what I make of it.' High external LOC: 'No matter how hard I try, luck determines what happens to me'; 'I have little influence over the things that happen to me.'

LOC is conceptualised as a continuum rather than a dichotomy — most people fall somewhere between extreme internal and external. It is partly dispositional (stable across situations) and partly situational (specific to domains).

Locus of Control and Stress

Internal LOC buffers the stress-health relationship through several mechanisms:

• Secondary appraisal: internals perceive themselves as having coping resources and agency — 'I can do something about this'. This enhances secondary appraisal of coping capacity (Lazarus), reducing the degree of stress experienced for any given threat.
• Active coping: internals are more likely to engage in problem-focused coping — addressing the source of the stressor. Problem-focused coping more effectively reduces stressors than avoidance or emotion-focused coping alone.
• Health-promoting behaviour: internals are more likely to adopt healthy behaviours (exercise, healthy diet, not smoking) because they believe their actions influence their health outcomes — reducing biological vulnerability to stress-related illness.

External LOC is associated with greater stress vulnerability: externals tend to use avoidant or passive coping strategies (since they believe outcomes are not in their control), report higher perceived stress, show greater physiological stress reactivity, and have higher rates of stress-related illness.

Research Evidence

Johnson and Sarason (1978) found that life events (SRRS) were more strongly associated with illness and depression in individuals with external LOC than in those with internal LOC — demonstrating that LOC moderates the stress-illness relationship. Internals can buffer the impact of even major life stressors through active coping, whilst externals show greater vulnerability.

Strickland (1978) reviewed the LOC-health literature and found that internal LOC was associated with: better information-seeking in health contexts; higher rates of preventive health behaviour; better management of chronic illness; and lower vulnerability to stress-induced illness. Syme (1990) found that low personal control — related to external LOC — was a significant predictor of cardiovascular disease, consistent with Marmot's Whitehall II data on job control.

Evaluation

LOC is a useful and well-validated individual difference variable with clear implications for stress management — enhancing perceived control is a therapeutic target in CBSM and SIT. Limitations: the general LOC scale may be too broad — domain-specific measures (health locus of control; work LOC) predict domain-specific outcomes better. Internal LOC is not universally adaptive — in situations that are genuinely uncontrollable (terminal illness, natural disaster), internal LOC may produce distress through futile control-seeking. The relationship between LOC and health is partly mediated by health behaviours — internals do not only appraise differently; they also behave differently. LOC itself may be partly a consequence of health — chronic illness reduces perceived control, creating reverse causation.