may be more externally focused and less sensitive to any internal changes. However, this
difference is not always consistent with differences in accuracy. Some research suggests
internal focus is related to overestimation. For example, Pennebaker (1983) reported
that individuals who were more focused on their internal states tended to overestimate
changes in their heart rate compared with subjects who were externally focused. In
contrast Kohlmann et al. (2001) examined the relationship between cardiac vigilance
and heart beat detection in the laboratory and reported a negative correlation; those who
stated they were more aware of their heart underestimated their heart rate. Being
internally focused has also been shown to relate to a perception of slower recovery from
illness (Miller et al. 1987) and to more health protective behaviour (Kohlmann et al.
2001). Being internally focused may result in a different perception of symptom change,
not a more accurate one.
Mood, cognitions, environment and symptom perception
Skelton and Pennebaker (1982) suggested that symptom perception is influenced by
factors such as mood, cognitions and the social environment.
Mood: The role of mood in symptom perception is particularly apparent in
pain perception with anxiety increasing self-reports of the pain experience (see Chapter
12 for a discussion of anxiety and pain). In addition, anxiety has been proposed as an
explanation for placebo pain reduction as taking any form of medication (even a sugar
pill) may reduce the individual’s anxiety, increase their sense of control and result in pain
reduction (see Chapter 13 for a discussion of anxiety and placebos). Stegen et al. (2000)
directly explored the impact of negative affectivity on both the experience of symptoms
and attributions for these symptoms. In an experimental study, participants were exposed
to low intensity somatic sensations induced by breathing air high in carbon dioxide. They
were then told that the sensation would be either positive, negative or somewhere
between and were asked to rate both the pleasantness and intensity of their symptoms.
The results showed that what the participants were told about the sensation influenced
their ratings of its pleasantness. The results also showed that although people who rated
high on negative affectivity showed similar ratings of pleasantness to those low on
negative affectivity they did report more negative meanings and worries about their
symptoms. This indicates that expectations about the nature of a symptom can alter the
experience of that symptom and that negative mood can influence the attributions made
about a symptom.
Cognition: An individual’s cognitive state may also influence their symptom per-
ception. This is illustrated by the placebo effect with the individual’s expectations of
recovery resulting in reduced symptom perception (see Chapter 13). It is also illustrated
by Stegen et al.’s (2000) study of breathing symptoms with expectations changing
symptom perception. Ruble (1977) carried out a study in which she manipulated
women’s expectations about when they were due to start menstruating. She gave sub-
jects an ‘accurate physiological test’ and told women either that their period was due
very shortly or that it was at least a week away. The women were then asked to report
any premenstrual symptoms. The results showed that believing that they were about
to start menstruating (even though they were not) increased the number of reported
ILLNESS COGNITIONS 59