et al. (2002) reported conscientiousness to significantly moderate the intention–behaviour
relationship, with higher levels of conscientiousness associated with stronger intention–
behaviour relationships (see also Conner, Rodgers and Murray, 2007). Conner et al.
(2009) showed intentions to be stronger predictors of resisting initiating smoking for
an adolescent sample with high rather than low levels of conscientiousness.
CONCLUSIONS
We have reviewed relationships between key personality traits and health outcomes
and considered some of the explanations of this relationship. Out of the Big Five
personality framework we noted that although there was as yet less evidence linking
openness to health outcomes, there was more evidence in relation to conscientiousness,
extraversion, neuroticism and agreeableness (when defined as high hostility), with better
health outcomes associated with high conscientiousness, high extraversion, low
neuroticism and high agreeableness (or low hostility). We also noted that a body of
research supports a link between optimism and positive health outcomes. The negative
impacts of type A behaviour pattern and hostility on health were also noted, particularly
in relation to the risk of coronary heart disease.
While discussing the effects of individual personality traits on health outcomes we
also noted a number of important explanations for the relationship between the two.
Table 6.1 provides a summary of these explanations and is worth reviewing now.
Not all these explanations constitute true causal mechanisms. Indeed part of the
problem in interpreting any relationship between personality and health is that the data
obtained is usually correlational (see Research methods 6.1).
A further explanation of the relationship between personality traits and health
outcomes is a measurement artefact explanation. Here the suggestion is that the
personality trait may cause differences in the way certain health outcomes (e.g.
symptoms) are reported. For example, we noted that, at least in relation to neuroticism,
some of the relationship between the personality trait and health outcomes may be
artefactual, caused by a reliance on self-report measures of symptoms (see Chapter 4).
This would account for the stronger relationship between neuroticism and symptom
reports compared to the relationship between neuroticism and non-self-report health
outcomes (e.g. illness).
The remaining explanations of the relationship between personality traits and
health outcomes are more easily interpreted as causal relationships. A key explanation
may be that personality traits can lead to health outcomes through physiological
mechanisms. So, for example, hostility might cause damage to arteries, which in turn
leads to a greater likelihood of heart disease. Another explanation focuses on the idea
that certain personality traits may be associated with approaching certain risky situations.
Friedman (2000) has referred to this idea as tropisms. Drawing on the analogy of
phototropic plants that move towards sources of light, the suggestion is that certain
personality types are drawn to particular situations, which then pose a risk to the
individual’s health. For example, extraverts might be more likely to seek out situations
where the risk of accidental injury is higher or where health risk behaviours such as
smoking or drug use are common. Relatedly, personality traits may lead to negative
health outcomes through changing engagement in health-related behaviours. We noted
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