MinireviewOptimism and immunity: Do positive thoughts always lead to positive effects?
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Optimism and immunity: the disappointment hypothesis
The failure of optimism to consistently predict better physical health indicators and outcomes is consistent with this pessimistic view of optimism: “The best doesn’t always occur. When things go wrong in a big way, the optimist may be particularly vulnerable.” (Tennen and Affleck, 1987, p. 382). According to this view, by virtue of having generally positive thoughts and feelings, optimists set themselves up for disappointment if the positive future they envision does not materialize. Their
Optimism and immunity: the engagement hypothesis
I have suggested an alternative hypothesis to explain negative effects of optimism on the immune system (see Fig. 1; Segerstrom, 2001, Segerstrom et al., 2003, Solberg Nes et al., in press). This hypothesis specifies that under difficult circumstances, more optimistic people remain engaged with those circumstances whereas more pessimistic people disengage, avoid, or give up. Giving up can be a physiologically protective response because stressor exposure is minimized in the short term by giving
Specific expectancies and immunity
The aforementioned studies focused on positive expectations for the future in general. However, people also have specific expectations about domains in their lives, events within those domains, and even behaviors within those events. In general, research has supported a more straightforward relationship between specific expectancies and immunity: positive specific expectancies reduce the immunological impact of stressors within that domain. For example, specific expectancies about law school
Conclusion
How optimism affects the immune system critically depends on the circumstances being examined. Under many circumstances, both dispositional optimism and specific expectancies appear to buffer the immune system from the effects of psychological stressors. However, there is sometimes a physiological cost to be paid for the optimistic strategy of engaging difficult stressors rather than disengaging and withdrawing. This physical cost is reflected in higher cortisol (Solberg Nes et al., in press)
Acknowledgments
This work was supported by the National Institutes of Health (MH61531) and a Research Committee Grant from the University of Kentucky.
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