Overview of Moderators
In a review paper published in Personality and Social Psychology Review (Helweg-Larsen & Shepperd, 2001), we reviewed the literature on variables that moderate (increase or decrease) the optimistic bias and examine whether the moderators influence the optimistic bias by affecting people’s personal estimates (called personal risk moderators) or by affecting people’s estimates of the average person’s risk (called target risk moderators). Moderators associated with negative affect (negative mood, dysphoria, trait and state anxiety, event severity, and proximity of feedback) and control related moderators (perceived control and prior experience) appear primarily to affect personal risk estimates. Positive mood affects target risk estimates. Finally, moderators that surround the comparison process appear to have different effects. Specifically, the type of comparison target appears to affect target risk estimates, whereas attention to personal risk-related behaviors affects personal risk estimates. This review continues to serve as a source of future hypotheses regarding how variables moderate the optimistic bias.
Perceived Control
I examined a specific moderator, namely perceived control in a paper published in Psychology and Health (Klein & Helweg-Larsen, 2002). We conducted a meta-analysis of 27 independent samples to examine the size of this relationship and examine what variables moderated the relationship. Greater perceived control was significantly related to greater optimistic bias. However, the relationship was moderated by participant nationality, student status, risk status, and the type of optimistic bias. Perceived control continues to be an important variable in my research, especially in examining the effect of experience on the optimistic bias.
Demographic moderators: Gender, Race and Socioeconomic Status
In a paper on gender differences in romantic relationships we found gender differences in how optimistic college students were with respect to their future likelihood of having a happy marriage or avoiding divorce (Helweg-Larsen, Harding and Klein, 2011). Men exhibited greater comparative optimism than women for having a happy marriage but not for getting divorced. For having a happy marriage and avoiding divorce, men exhibited greater personal optimism relative to women. Importantly experience (with parental divorce) moderated the gender difference in personal optimism and perceived control partially mediated the gender difference in comparative optimism (but only for having a happy marriage) and in personal optimism (for both having a happy marriage and avoiding divorce).
Risk biases such as comparative optimism (thinking one is better off than similar others) and risk inaccuracy (misestimating one’s risk compared to one’s calculated risk) for health outcomes are common. In this paper we investigated racial or socioeconomic differences in these risk biases (Peterson, Helweg-Larsen, Volpp, & Kimmel, 2012). Results from a survey of individuals with poorly controlled hypertension (N=813) indicated that participants showed (1) comparative optimism for heart attack risk by underestimating their heart attack risk compared to similar others, and (2) risk inaccuracy by overestimating their heart attack risk compared to their calculated heart attack risk. More highly educated participants were more comparatively optimistic because they rated their personal risk as lower; education was not related to risk inaccuracy. Neither race nor the federal poverty level was related to risk biases. Worry partially mediated the relationship between education and personal risk.
Time as a Moderator: Stability of the Optimistic Bias
In a paper published in Personality and Social Psychology Bulletin we (Shepperd, Helweg-Larsen, and Ortega, 2003) examined the stability of optimistic beliefs, both across time and across types of events. Both studies found strong evidence for consistency across time and some evidence for consistency across events. The consistency across time and events was moderated by experience. Specifically, when viewed together the studies suggest that experience produces an initial decrease in the consistency of comparative judgments (Study 2), followed by greater consistency in subsequent judgments (Study 1).