Abstract
It is a puzzle why humans tend toward unrealistic optimism, as it can lead to excessively risky behavior and a failure to take precautionary action. Using data from a large nationally representative U.K. sample (�=36,312), our claim is that optimism bias is partly a consequence of low cognition—as measured by a broad range of cognitive skills, including memory, verbal fluency, fluid reasoning and numerical reasoning. We operationalize unrealistic optimism as the difference between a person’s financial expectation and the financial realization that follows, measured annually over a decade. All else being equal, those highest on cognitive ability experience a 22% (53.2%) increase in the probability of realism (pessimism) and a 34.8% reduction in optimism compared with those lowest on cognitive ability. This suggests that the negative consequences of an excessively optimistic mindset may, in part, be a side product of the true driver, low cognitive ability.
You can avoid reality, but you cannot avoid the consequences of avoiding reality.
—Ayn Rand
Introduction
Unrealistic optimism or optimism bias—the tendency for individuals to overestimate the chance of favorable outcomes occurring and underestimate the chance of bad (
Weinstein, 1980)—has been found to be one of the most pervasive human traits across many domains (
Sharot, 2011). For instance, research has shown that individuals tend to underestimate the likelihood of developing a drinking problem or getting divorced (
Weinstein, 1980) and to overestimate their future earnings (
Dawson, 2017) and how long they are going to live (
Puri & Robinson, 2007). Our established tendency toward unrealistic optimism poses an evolutionary puzzle as normative models of human judgment, like expected utility theory, suggest unbiased assessments of probabilities are advantageous. Like any other judgmental bias, optimism bias distorts the decision-making process, leading to systematic decision errors, increased rash and risky behavior (
de Meza et al., 2019) and a failure to take precautionary measures (
Dillard et al., 2009).
Explanations of this puzzle have tended to focus on the idea that beliefs are self-serving and are “chosen” to fulfill certain psychological needs (
S. E. Taylor & Brown, 1988). More specifically, research has pointed to the immediate affective benefits of unrealistic optimism, such as enhanced psychological well-being and self-esteem (
Pyszczynski et al., 1987), improvements in our ability to cope with negative feedback (
S. E. Taylor & Brown, 1988), and the ability to savor in our future successes (
Brunnermeier & Parker, 2005;
Loewenstein, 2006). Indeed, the motivation to maintain an optimistic view of the future can be significant, with the anticipation of unpleasant events having an equally, if not greater, impact on distress levels than the event itself (
Berns et al., 2006;
Nosarti et al., 2002).
While these affective benefits are thought to provide the incentives for unrealistic optimism, research has also highlighted the channels through which optimism bias can be maintained in the presence of reality and constant feedback from our environment. For instance, the literature has provided an abundance of empirical evidence on the phenomenon of asymmetric information integration—the idea that humans are better at integrating positive information into their beliefs than negative information (
Drobner, 2022;
Eil & Rao, 2011;
Sharot, 2011;
Sharot et al., 2011).
Sharot et al. (2011) found that when participants re-estimated their likelihood of experiencing 80 different types of adverse life events, they updated their beliefs optimistically when they were provided with desirable information about the average probabilities of these events (i.e., when the average probability of experiencing the event was lower than the participants’ original estimate) but neutrally when new information was undesirable (i.e., when the average probability of experiencing the event was higher than the participants’ original estimate). It has also been well documented that humans are better at recollecting good events or past successes than they are at recollecting bad ones or failures (
Histed et al., 2009) and are more likely to attribute past success to their own skill, while failures are attributed to bad luck (
Langer & Roth, 1975;
Seligman, 1990).
Despite the significant evidence on the affective incentives that motivate optimism, the asymmetric information processing and recall mechanisms that help maintain an optimistic mindset and the fact that over 1,000 articles have been published on unrealistic optimism in the last four decades (
Shepperd et al., 2017), it remains untested whether this miscalibration is to some extent a consequence of cognitive (in)ability. This article attempts to address this gap in the literature.
There are reasons for expecting that the optimism bias may be associated with cognitive ability. This follows from the emphasis placed on the “two-system” or “dual-process” approach to decision-making in the heuristics and biases literature (
Fudenberg & Levine, 2006;
Kahneman & Frederick, 2005;
Stanovich, 1999;
Thaler & Shefrin, 1981). Here, the two systems are labeled as System 1, where reasoning is intuitive, effortless, impulsive, affective and emotional, and System 2, where reasoning is deliberative, logical, and analytical. This two-system model of cognition embodies the assumption that judgmental biases, like unrealistic optimism, are universal properties of System 1, a heuristic system that operates with little or no effort and no sense of voluntary control (
Tversky & Kahneman, 1996). However, the presence of judgmental biases can vary from person to person because heuristic responses can sometimes be overridden by System 2, the system that allocates attention to effortful mental activities