Behavioral Research

Table of Contents
1 Definition and History

Measurement and Methodological Issues


Utility of Construct


Related Constructs




Measures Appendix

7 Published Examples

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Other Constructs



Dispositional Optimism




Illness Representations

  Implementation Intentions
  Intention, Expectation, and Willingness
  Normative Beliefs
  Optimistic Bias
  Perceived Benefits
  Perceived Control
  Perceived Severity
  Perceived Vulnerability
  Self-Reported Behavior
  Social Influence
  Social Support

Optimistic Bias
William M. P. Klein

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Related Constructs

Optimistic biases are thought to represent one example of an array of self-serving beliefs that may influence behavior including the illusion of control (Langer, 1975), the better-than-average effect (e.g., Alicke et al., 1995), and the uniqueness bias (Goethals, Messick, & Allison, 1991). People who overestimate their ability to control an outcome may engage in more risky decisions and behaviors (Klein & Kunda, 1994). Perceptions of control and self-efficacy represent key components of many models such as Social Cognitive Theory (Bandura, 2001) and the Theory of Planned Behavior (Ajzen, 1991), highlighting the importance that biases in control and efficacy beliefs might play in health behavior.

It is notable that optimistic beliefs and health threats seem to be only weakly associated with dispositional optimism (e.g., Goodman, Chesney, & Tipton, 1995; Taylor et al., 1992), including when these optimistic beliefs are biased (Radcliffe & Klein, 2002). There is some evidence that dispositional optimism may interact with optimistic bias to magnify the detrimental effect of bias on information processing (Davidson & Prkachin, 1997), although in this study optimistic bias was measured as a sum of risk estimates across several events without use of an accuracy criterion. Generally, people who are high in dispositional optimism (or a health-specific form of optimism) are more knowledgeable, less defensive in response to health information, and in better health (Aspinwall & Brunhart, 1996; Scheier & Carver, 1992), suggesting that dispositional optimism and optimistic biases may have opposing effects (Radcliffe & Klein, 2002).

Although much research has investigated the underlying causes and moderators of optimistic biases, less work has addressed how optimistically biased beliefs are related to health information processing, behavior, and physical health outcomes. Moreover, methodological problems make it difficult to determine how biases in risk perceptions influence these outcomes relative to other constructs in health behavior models such as attitudes and self-efficacy (Weinstein, 2005) as well as less traditional constructs like affect (McCaul & Mullens, 2003). In order to properly assess the impact of optimistic biases, it is important to use accuracy criteria that identify optimistic biases at the level of the individual. The increasing availability of risk engines such as the Harvard Risk Index (Colditz et al., 2000) and the use of prospective designs should facilitate research taking this approach.

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