Paul D Windschitl

• Ph.D. Iowa State University
• University of Iowa

Background: Icon arrays, which visually depict frequencies, are commonly recommended for communicating risk information like survival rates. However, they have been found to be ineffective at buffering against motivated reasoning that can lead to undue optimism. To determine whether the impersonal frequency format of icon arrays (reporting a number...

Background: For assessing the impact of risk perceptions on prevention efforts or behavior change, best practices involve conditional risk measures, which ask people to estimate their risk contingent on a course of action (e.g., “if not vaccinated”). Purpose: To determine whether the use of conditional wording—and its drawing of attention to one sp...

Past research on advice-taking has suggested that people are often insensitive to the level of advice independence when combining forecasts from advisors. However, this has primarily been tested for cases in which people receive numeric forecasts. Recent work by Mislavsky & Gaertig (2022) shows that people sometimes employ different strategies when...

Background To assess the impact of risk perceptions on prevention efforts or behavior change, best practices involve conditional risk measures, which ask people to estimate their risk contingent on a course of action (e.g., “if not vaccinated”). Purpose To determine whether the use of conditional wording—and its drawing of attention to one specifi...

During a global crisis, does the desire for good news also mean an endorsement of an optimistic bias? Five pre‐registered studies, conducted at the start of the COVID pandemic, examined people's lay prescriptions for thinking about uncertainty—specifically whether they thought forecasters should be optimistic, realistic, or pessimistic in how they...

During a global crisis, does the desire for good news also mean an endorsement of an optimistic bias? Five pre-registered studies, conducted at the start of the COVID pandemic, examined people’s lay prescriptions for thinking about uncertainty—specifically whether they thought forecasters should be optimistic, realistic, or pessimistic in how they...

Assessing perceived vulnerability to a health threat is essential to understanding how people conceptualize their risk, and to predicting how likely they are to engage in protective behaviors. However, there is limited consensus about which of many measures of perceived vulnerability predict behavior best. We tested whether the ability of different...

Objectives: To examine whether presenting a 30% or a 60% chance of survival in different survival information formats would influence hypothetical periviable birth treatment choice and whether treatment choice would be associated with participants' recall or their intuitive beliefs about the chances of survival. Study design: An internet sample...

The desirability bias (or wishful thinking effect) refers to when a person's desire regarding an event's occurrence has an unwarranted, optimistic influence on expectations about that event. Past experimental tests of this effect have been dominated by paradigms in which uncertainty about the target event is purely stochastic—i.e., involving only a...

The desirability bias refers to when people’s expectations about an uncertain event are biased by outcome preferences. Prior work has provided limited evidence that the magnitude of this motivated bias depends on (is moderated by) how expectations are solicited—as discrete outcome predictions or as likelihood judgments expressed on more continuous...

The desirability bias refers to when people’s expectations about an uncertain event are biased by outcome preferences. Prior work has provided limited evidence that the magnitude of this motivated bias depends on (is moderated by) how expectations are solicited—as discrete outcome predictions or as likelihood judgments expressed on more continuous...

Past work has suggested that people prescribe optimism-believing it is better to be optimistic, instead of accurate or pessimistic, about uncertain future events. Here, we identified and addressed an important ambiguity about whether those findings reflect an endorsement of biased beliefs-that is, whether people prescribe likelihood estimates that...

The phenomenon of ambiguity aversion suggests that people prefer options that offer precisely rather than imprecisely known chances of success. However, past work on people's responses to ambiguity in health treatment contexts found ambiguity seeking rather than aversion. The present work addressed whether such findings reflected a broad tendency f...

Past work has suggested that people prescribe optimism—believing it is better to be optimistic, instead of accurate or pessimistic, about uncertain future events. Here, we identified and addressed an important ambiguity about whether those findings reflect an endorsement of biased beliefs—i.e., whether people prescribe likelihood estimates that ref...

When making decisions involving risk, people may learn about the risk from descriptions or from experience. The description-experience gap refers to the difference in decision patterns driven by this discrepancy in learning format. Across two experiments, we investigated whether learning from description versus experience differentially affects the...

People often use tools for tasks, and sometimes there is uncertainty about whether a given task can be completed with a given tool. This project explored whether, when, and how people's optimism about successfully completing a task with a given tool is affected by the contextual salience of a better or worse tool. In six studies, participants were...

The current study tested relative strengths of different comparison beliefs for predicting people’s self-assessments of whether they should increase their health-relevant behaviors (exercise, sleep, and fruit and vegetable consumption). Comparison beliefs relevant to three standards (perceived global, local, expert standards) were evaluated. Data w...

The current study tested relative strengths of different comparison beliefs for predicting people’s self-assessments of whether they should increase their health-relevant behaviors (exercise, sleep, and fruit and vegetable consumption). Comparison beliefs relevant to three standards (perceived global, local, expert standards) were evaluated. Data w...

Risk perception is an important construct in many health behavior theories. Smoking risk perceptions are thoughts and feelings about the harms associated with cigarette smoking. Wide variation in the terminology, definition, and assessment of this construct makes it difficult to draw conclusions about the associations of risk perceptions with smoki...

Two studies investigating if the amount of wishful thinking changes as a function of the number of outcomes.

Judgments of direct comparisons, probabilities, proportions, and ranks can all be considered referent-specific judgments, for which a good estimate requires a target to be compared against a referent(s). This paper presents a Referent-Specific Judgment Framework (RSJF) to organize and integrate over- and under-estimation biases commonly associated...

People sometimes modify their behavior based on whether they believe they do more or less of that behavior than others. But are people's perceptions of their social-comparative status for behaviors generally accurate? The current research assessed accuracy and bias in perceived social-comparative status for a number of health-related behaviors. In...

People sometimes modify their behavior based on whether they believe they do more or less of that behavior than others. But are people’s perceptions of their social-comparative status for behaviors generally accurate? The current research assessed accuracy and bias in perceived social-comparative status for a number of health-related behaviors. In...

Background: Prescription monitoring programs (PMPs) can provide health care professionals with valuable information. However, few studies have explored providers' decision making for accessing PMPs. Aims: This study aimed to identify provider characteristics and situational factors most influencing perceived importance of consulting the PMP for...

Objective: Health communications are often viewed by people with varying levels of risk. This project examined, in the context of radon risk messages, whether information relevant to high-risk individuals can have an unintended influence on lower-risk individuals. Two studies assessed whether information about lung cancer risk from smoking reduced...

This project focuses on what we call referent-specific judgments (i.e., judgments that require specific comparisons). They can have many forms—including comparative judgments, probability judgments, proportion estimates, and ranks—but the different forms seem vulnerable to similar biases. We present a Referent-Specific Judgment Framework (RSJF) aim...

Past research on the desirability bias and on bracing for bad news has focused on the potential influence of outcome desirability on people's stated expectations. The present studies examined its influence on behavior—that is, what is done in anticipation of, or preparation for, an uncertain outcome. In five studies, the desirability of possible ou...

When people encounter potential hazards, their expectations and behaviours can be shaped by a variety of factors including other people's expressions of verbal likelihood (e.g., unlikely to harm). What is the impact of such expressions when a person also has numeric likelihood estimates from the same source(s)? Two studies used a new task involving...

Preliminary studies examining how the type of prediction one is making influences the strength of the preference-expectation link

How receiving additional information impacts the desirability bias.

Understanding how healthfully people think they eat compared to others has implications for their motivation to engage in dietary change and the adoption of health recommendations. Our goal was to investigate the scope, sources, and measurements of bias in comparative food consumption beliefs. Across 4 experiments, participants made direct comparis...

This chapter discusses various types of optimism biases and the causes of those biases. It suggests that the field sorely needs more consistency in its use of terms related to optimism biases. The chapter discusses definitions for relevant terms and identify key features of various forms of bias. It also provides a framework for understanding relat...

The biasing influence of anchors on numerical estimates is well established, but the relationship between knowledge level and the susceptibility to anchoring effects is less clear. In two studies, we addressed the potential mitigating effects of having knowledge in a domain on vulnerability to anchoring effects in that domain. Of critical interest...

Previous research on political stereotypes has focused on the perceived moral values or political attitudes of conservatives and liberals. The current studies examined whether laypeople hold stereotypes about the psychological traits of Republicans and Democrats and whether those stereotypes represent exaggerations of actual political differences....

Four experiments examined projection and egocentrism in people’s expectations about how a treatment they tried would impact others. In Experiment 1, people’s expectations and recommendations for others aligned heavily with their own experience even though they directly witnessed a co-participant’s contradictory experience. Experiments 2 and 3 exami...

Effects of exposure to a severe weather disaster on perceived future vulnerability were assessed in college students, local residents contacted through random-digit dialing, and community residents of affected versus unaffected neighborhoods. Students and community residents reported being less vulnerable than their peers at 1 month, 6 months, and...

Previous research into the relationship between knowledge level and anchoring effects has led to mixed conclusions. This paper presents four studies that used a diverse set of stimuli and paradigms to further investigate this relationship. In Study 1, greater knowledge was associated with smaller anchoring effects—both when knowledge was measured u...

Five studies tested when and why individuals engage in confirmatory information searches (selective exposure) following predictions. Participants engaged in selective exposure following their own predictions, even when their predictions were completely arbitrary (Studies 1 and 3). The selective exposure was not simply the result of a cognitive bias...

Three experiments were conducted to test the robustness and explanations of the Nonselective Superiority Bias (NSSB), whereby any randomly selected item from a positive category is rated more favorably when compared with a cohesive group of other exemplars from the same category. Having participants rank order all exemplars prior to making a direct...

When judging their likelihood of success in competitive tasks, people tend to be overoptimistic for easy tasks and overpessimistic for hard tasks (the shared circumstance effect; SCE). Previous research has shown that feedback and experience from repeated-play competitions has a limited impact on SCEs. However, in this paper, we suggest that compet...

Patient preferences should be taken into account by clinicians when treatment planning. The purposes of this study were to describe the number of visits patients preferred when undergoing root canal therapy (RCT) and to assess whether their preferences were related to hypothetical treatment success rates. Self-administered questionnaires were maile...

People must often engage in sequential sampling in order to make predictions about the relative quantities of two options. We investigated how directional motives influence sampling selections and resulting predictions in such cases. We used a paradigm in which participants had limited time to sample items and make predictions about which side of t...

The goal of the current research was to test whether direct versus indirect measures of comparative optimism yield different results as a function of health risk severity and prevalence. A random-digit sample of community residents (N = 259) responded to interview questions about perceived vulnerability using both direct (i.e. self-to-peer risk) an...

Two experiments examined the interplay of consensus information and situational information in shaping trait inferences. Participants read scenarios that described a target person's behavior (e.g., Matt volunteered to clean up after a park tour) and made trait inferences (e.g., perceived helpfulness) about the target and relevant population (e.g.,...

People must often perform calculations in order to produce a numeric estimate (e.g., a grocery-store shopper estimating the total price of his or her shopping cart contents). The current studies were designed to test whether estimates based on calculations are influenced by comparisons with irrelevant anchors. Previous research has demonstrated tha...

Using a cancer-treatment scenario, we tested whether descriptive norm information (e.g., the proportion of other people choosing a particular treatment) would influence people's hypothetical treatment choices. Women from an Internet sample (Study 1 N=2238; Study 2 N=2154) were asked to imagine deciding whether to take adjuvant chemotherapy followin...

Does desire for an outcome inflate optimism? Previous experiments have produced mixed results regarding the desirability bias, with the bulk of supportive findings coming from one paradigm--the classic marked-card paradigm in which people make discrete predictions about desirable or undesirable cards being drawn from decks. We introduce a biased-gu...

Purpose: Previous research (e.g. Klein, Windschitl, Lipkus, Fagerlin) has shown that providing people with comparative risk information (i.e., whether their risk is above or below average) can change risk perceptions and subsequent health behaviors. As part of a larger study on contextual risk information, we explored whether comparative risk statu...

The notion that desire for an outcome inflates optimism about that outcome has been dubbed the desirability bias or wishful thinking. In this paper, we discuss the importance of distinguishing wishful thinking from the more general concept of motivated reasoning, and we explain why documenting overoptimism or correlations between preferences and op...

Three studies examined the influence of comparison-referent exposure (i.e., the frequency with which one views comparison referents) on evaluations of the ability of a target person (either oneself or another person). In Experiment 1, participants performed a task and then viewed performances of both upward and downward referents. Participants who...

People are often egocentric when judging their likelihood of success in competitions, leading to overoptimism about winning when circumstances are generally easy and to overpessimism when the circumstances are difficult. Yet, egocentrism might be grounded in a rational tendency to favor highly reliable information (about the self) more so than less...

Recent research has raised questions regarding the consistency of unrealistic optimism and related self-enhancing tendencies, both within cultures and across cultures. The current study tested whether the method used to assess unrealistic optimism influenced cross-cultural patterns in the United States and Japan. The results showed that the direct...

People have more information about themselves than others do, and this fundamental asymmetry can help to explain why individuals have difficulty accurately intuiting how they appear to other people. Determining how one appears to observers requires one to utilize public information that is available to observers, but to disregard private informatio...

People tend to egocentrically focus on how adverse or beneficial conditions in competitions affect the self, while inadequately considering the comparable impact on opponents. This leads to overoptimism for a victory in easy tasks and underoptimism in hard tasks. Four experiments investigated whether experience and performance feedback in a multi-r...

Prior work has found that when people compare themselves with others they egocentrically focus on their own strengths and achievements more than on the (equally relevant) strengths and achievements of the comparison group. As a consequence, people tend to overestimate their comparative standing when absolute standing is high and underestimate their...

The authors used a frequency sampling paradigm to investigate how perceptions of a minority group's size and influence are affected by the manner in which the subgroup structure of the minority is presented. Participants in two experiments read sequentially sampled opinions that hypothetical members of a committee supposedly held about a controvers...

Above-average and below-average effects appear to be common and consistent across a variety of judgment domains. For example, several studies show that individual items from a high- (low-) quality set tend to be rated as better (worse) than the other items in the set (e.g., E. E. Giladi & Y. Klar, 2002). Experiments in this article demonstrate reve...

Although team allegiance is usually associated with optimistic predictions about team performance, the authors hypothesized that preferences for one’s group can also lead to pessimistic predictions. Upon arrival to the laboratory, groups of four participants were split into teams of two based on bogus criteria. Participants were informed that their...

People are often presumed to be vulnerable to a desirability bias, namely, a tendency to be overoptimistic about a future outcome as a result of their preferences or desires for that outcome. In this article, this form of wishful thinking is distinguished from the more general concepts of motivated reasoning and overoptimism, and the evidence for t...

Two experiments tested the influence of three task factors on respondents' tendency to use normative, heuristic, and random approaches to making likelihood judgments about polychotomous cases (i.e., cases in which there is more than one alternative to a focal hypothesis). Participants estimated their likelihood of winning hypothetical raffles in wh...

Biases in social comparative judgments, such as those illustrated by above-average and comparative-optimism effects, are often regarded as products of motivated reasoning (e.g., self-enhancement). These effects, however, can also be produced by information-processing limitations or aspects of judgment processes that are not necessarily biased by mo...

The judged likelihood of a focal outcome should generally decrease as the list of alternative possibilities increases. For example, the likelihood that a runner will win a race goes down when 2 new entries are added to the field. However, 6 experiments demonstrate that the presence of implausible alternatives (duds) often increases the judged likel...

Three studies investigated the role of nonmotivated egocentric processes in comparative optimism (and pessimism). According to an egocentric-processes account, when people judge their comparative likelihood of experiencing an event (e.g., "Compared to the average person, how likely are you to become wealthy?"), they consider their own chances of ex...

Six experiments investigated people's optimism in competitions. The studies involved hypothetical and real competitions (course grades in Experiments 1 and 2, a trivia game in Experiments 3-5, and a poker game in Experiment 6) in which the presence of shared adversities and benefits (factors that would generally hinder or help the absolute performa...

When providing a probability estimate for an event, experts often supply reasons that they expect will clarify and support that estimate. We investigated the possible unintended influence that these reasons might have on a listener's intuitive interpretation of the event's likelihood. Experiments 1 and 2 demonstrated that people who read positive r...

Previous research has demonstrated that intuitive perceptions of certainty regarding a focal outcome are sensitive to variations in how evidence supporting nonfocal alternatives is distributed, even when such variations have no bearing on objective probability. We investigated this alternative-outcomes effect in a learning paradigm in which partici...

Four experiments investigated how people's perceptions about a group's (e.g., women's) vulnerability to a disease are influenced by information about the prevalence of the disease in a comparable group (e.g., men). Participants read symptom and prevalence infomation about fictitious diseases before answering questions regarding target group vulnera...

A standard method for assessing whether people have appropriate internal representations of an event's likelihood is to check whether their subjective probability or frequency estimates for the event correspond with the assumed objective value for that event. When a person's estimate for the event exceeds its assumed objective probability or freque...

Recent research has demonstrated that the perceived certainty of a focal outcome depends not only on the overall amount of evidence supporting the alternatives to the focal outcome, but also on how that evidence is distributed across those alternatives (e.g., Windschitl & Wells, 1998). Three experiments replicated this alternative-outcomes effect a...

People's numeric probability estimates for 2 mutually exclusive and exhaustive events commonly sum to 1.0, which seems to indicate the full complementarity of subjective certainty in the 2 events (i.e., increases in certainty for one event are accompanied by decreases in certainty for the other). In this article, however, a distinction is made betw...

Past research has demonstrated that interpretations of vague verbal forecasts (e.g., "likely") differ as a function of the context to which they refer. Experiments 1 and 2 demonstrate that precise numeric forecasts (e.g., "70%") are also susceptible to such context effects. Participants read descriptions of target events and experts' numeric foreca...

Past research has demonstrated that interpretations of vague verbal forecasts (e.g., "likely") differ as a function of the context to which they refer Experiments 1 and 2 demonstrate that precise numeric forecasts (e.g.,'"70%") are also susceptible to such context effects. Participants read descriptions of target events and experts' numeric forecas...

The authors discuss the problem with failing to sample stimuli in social psychological experimentation. Although commonly construed as an issue for external validity, the authors emphasize how failure to sample stimuli also can threaten construct validity. They note some circumstances where the need for stimulus sampling is less obvious and more ob...

Distributions of possible scenario outcomes were manipulated without changing the probabilities of focal outcomes (e.g., you hold 3 raffle tickets and 7 other people each hold 1 vs. you hold 3 and another person holds 7). Participants' probability estimates confirmed that beliefs about the objective likelihood of the focal outcomes were largely una...

Distributions of possible scenario outcomes were manipulated without changing the probabilities of focal outcomes (e.g., you hold 3 raffle tickets and 7 other people each hold 1 vs. you hold 3 and another person holds 7). Participants' probability estimates confirmed that beliefs about the objective likelihood of the focal outcomes were largely una...

The authors argue that alternatives to the traditional numeric methods of measuring people's uncertainty may prove to hold important advantages under some conditions. In 3 experiments, the authors compared verbal measures involving responses such as very likely , and numeric measures involving responses such as 80% chance . The verbal measures were...

The authors argue that alternatives to the traditional numeric methods of measuring people's uncertainty may prove to hold important advantages under some conditions. In 3 experiments, the authors compared verbal measures involving responses such as very likely, and numeric measures involving responses such as 80% chance. The verbal measures were f...

Four experiments investigated whether and how interpolated faces cause impairment to memories for related target faces. Participants viewed target faces and then saw a presentation of interpolated faces that were related to some of the targets. Modified tests, which offered target and novel faces as recognition alternatives, detected impairment eff...

Four experiments investigated whether and how interpolated faces cause impairment to memories for related target faces. Participants viewed target faces and then saw a presentation of interpolated faces that were related to some of the targets. Modified tests, which offered target and novel faces as recognition alternatives, detected impairment eff...

Base rates have no necessary relation to judgments that are not themselves probabilities. There is no logical imperative, for instance, that behavioral base rates must affect causal attributions or that base rate information should affect judgments of legal liability. Decision theorists should be cautious in arguing that base rates place normative...

Suggests that detecting memory impairment with the modified test relies on long retention intervals that provide the necessary forgetting of event information for impairing effects of postevent misinformation to occur. 288 Ss were tested in 4 experiments that presented event items centrally, introduced verbal postevent items to a misled condition,...