| Ambiguity intolerance and evaluative need |
People are motivated to understand personally relevant symptoms of undiagnosed diseases, because uncertainty is discomforting |
| Misattribution of arousal |
People are often not accurate in determining the causes of symptoms |
| Salience bias |
People are more motivated to evaluate symptoms when symptom attributes are: (a) ‘salient’ (noticeable), unexpected or relevant to their prior health status; (b) ‘consequential’ in terms of being intolerable or disruptive. |
| ‘Common-sense’ models [32] or illness prototypes [33] |
People develop ‘common-sense’ models, or prototypes of illness based on their own experience of health services and by social comparison with others. These prototypes may be activated by the appearance of symptoms. |
| Prototype matching |
The more symptoms people can match to their ‘common-sense’ models, or illness prototypes, that they know about, the more likely they are to invoke that illness label. Conditions with low base rates are less likely to be selected as the cause of symptoms than more common disorders [32]. |
Optimism bias
|
People tend to appraise symptoms as less-serious, transient and self-correcting, rather than life-threatening, chronic and requiring medical assistance, especially when symptoms are diffuse or confusing. |
| Symptom ambiguity and subjective uncertainty |
When symptoms are more diffuse (e.g. fatigue) rather than specific and localised (e.g. rectal bleeding), there are a greater number of ‘common-sense’ models, or illness prototypes, to choose from, and there is a greater chance of misinterpreting the symptoms. |
Anchoring and adjustment
|
Individuals are more likely to notice symptoms which are a good fit with their ‘common-sense’ models, or illness prototypes. People are selective in the way in which they monitor and test hypotheses about different events. As symptoms proliferate, worsen or improve, beliefs about the underlying illness change. |
