We develop a modified ultimatum game, in which the proposer gives two offers, and the responder selects one offer out of the two without seeing them. Then, the selected offer becomes the relevant offer, and the unselected offer becomes the irrelevant one. Finally, the responder evaluates the fairness of the pair of offers and makes a hypothetical decision whether to accept or reject the relevant offer. For most of our subjects, the level of the irrelevant offer positively affects fairness perceptions and willingness to accept, even though the irrelevant offer cannot be accepted. The reason is that the irrelevant offer does signal the proposer’s intentions. Most responders give more weight to the relevant offer than to the irrelevant offer in evaluating fairness and in the willingness to accept. We call this effect the relevance effect. This effect is expected when considering the willingness to accept. However, it is unclear why the relevant offer should carry more weight when evaluating fairness, because the proposer makes the two offers together without knowing which one will become the relevant one. Therefore, this behavior can be considered a bias in fairness evaluations.

When choosing between immediate and future rewards, how do people deal with uncertainty about the value of the future outcome or the delay until its occurrence? Skylark et al. (2020) suggested that people employ a delay-reward heuristic: the inferred value of an ambiguous future reward is a function of the stated delay, and vice-versa. The present paper investigates the role of this heuristic in choice behaviour. In Studies 1a–2b, participants inferred the value of an ambiguous future reward or delay before the true value was revealed and a choice made. Preference for the future option was predicted by the discrepancy between the estimated and true values: the more pleasantly surprising the delayed option, the greater the willingness to choose it. Studies 3a–3c examined the association between inference and preference when the ambiguous values remained unknown. As predicted by the use of a delay-reward heuristic, inferred delays and rewards were positively related to stated rewards and delays, respectively. More importantly, choices were associated with inferred rewards and, in some circumstances, delays. Critically, estimates and choices were both order-dependent: when estimates preceded choices, estimates were more optimistic (people inferred smaller delays and larger rewards) and were subsequently more likely to choose the delayed option than when choices were made before estimates. These order effects argue against a simple model in which people deal with ambiguity by first estimating the unknown value and then using their estimate as the basis for decision. Rather, it seems that inferences are partly constructed from choices, and the role of inference in choice depends on whether an explicit estimate is made prior to choosing. Finally, we also find that inferences about ambiguous delays depend on whether the estimate has to be made in “days” or in a self-selected temporal unit, and replicate previous findings that older participants make more pessimistic inferences than younger ones. We discuss the implications and possible mechanisms for these findings.

Are groups of people better able to minimize a collective loss if there is a collective target that must be reached or if every small contribution helps? In this paper we investigate whether cooperation in social dilemmas can be increased by structuring the problem as a step-level social dilemma rather than a linear social dilemma and whether cooperation can be increased by manipulating endowment asymmetry between individuals. In two laboratory experiments using ‘Public Bad’ games, we found that that individuals defect less and are better able to minimize collective and personal costs in a step-level social dilemma than in a linear social dilemma. We found that the level of cooperation is not affected by an ambiguous threshold: even when participants cannot be sure about the optimal cooperation level, cooperation remains high in the step-level social dilemmas. We find mixed results for the effect of asymmetry on cooperation. These results imply that presenting social dilemmas as step-level games and reducing asymmetry can help solve environmental dilemmas in the long term.

In social interactions, people frequently encounter gain (i.e., all outcomes aregains from the status-quo) or loss (all outcomes are losses from the status-quo)social dilemmas, where their personal interests conflict with social interests.We ask whether there are any behavioral differences in social interactions whenit comes to gains and losses. Using the Prisoner’s Dilemma games, inthree studies we observed that participants were less cooperative in the lossdomain than in the gain domain. This effect was robust, not moderated by payoffamount (Study 1), cooperation index (Study 1), domain comparison (Studies 1 and2), and personal loss aversion (Study 3). Social motive and belief explainedthis effect: compared to the gain domain, participants in the loss domainaroused more pro-self motive and less prosocial motive, and showed strongerbeliefs that their partner would defect, which led them to cooperate less. Thesefindings suggest that gain and loss domains affect individual motivation andbelief, subsequently affecting strategic choices in social dilemmas.

Time preference reversal refers to systematic inconsistencies between preferences and bids for intertemporal options. From the two eye-tracking studies (N1 = 60, N2 = 110), we examined the underlying mechanisms of time preference reversal. We replicated the reversal effect in which individuals facing a pair of intertemporal options choose the smaller-sooner option but assign a higher value to the larger-later one. Results revealed that the mean fixation duration and the proportion of gaze time on the outcome attribute varied across the choice and bid tasks. In addition, time preference reversals correlated with individual differences in maximizing tendencies. Findings support the contingent weighting hypothesis and strategy compatibility hypothesis and allow for improved theoretical understanding of the potential mechanisms and processes involved in time preference reversals.

Indoor climate interventions are often motivated from a worker comfort and productivity perspective. However, the relationship between indoor climate and human performance remains unclear. We assess the effect of indoor climate factors on human performance, focusing on the impact of indoor temperature on decision processes. Specifically, we expect heat to negatively influence higher cognitive rational processes, forcing people to rely more on intuitive shortcuts. In a laboratory setting, participants (N=257) were exposed to a controlled physical environment with either a hot temperature (28° C) or a neutral temperature (22° C) over a two-hour period, in which a battery of validated tests were conducted. We find that heat exposure did not lead to a difference in decision quality. We did find evidence for a strong gender difference in self-report, such that only men expect that high temperature leads to a significant decline in performance, which does in fact not materialize. These results cast doubt on the validity of self-report as a proxy for performance under different indoor climate conditions.

In classic research on judgment and decision making under risk, risk is described by providing participants with the respective outcomes and probabilities in a summary format. Recent research has introduced a different paradigm – decisions-by-experience – where participants learn about risk by sampling from the outcomes, rather than by summary descriptions. This latter research reports a description-experience gap, indicating that some of the classic patterns of risk attitude reverse when people experience the risk. Recent research has attempted to investigate risky choice framing in the decisions-by-experience paradigm. I discuss how this research runs into problems in properly manipulating framing in decisions by experience. Drawing from framing research with animals, I argue that framing effects also exist in experience tasks. The classic Asian Disease task, however, awaits proper translation into an experience paradigm.

How often and for how long a certain object was encountered are two distinct questions, requiring two distinct answers. But when humans judge an object to have been presented often, they usually also judge it to have been presented for a long duration. Under certain conditions the reverse is also true: When an object has been presented for a long time, humans think it has been presented often. These mutual influences hint at a single underlying dimension on which judgments of frequency and duration are based. But the judgments also differ in certain respects, which instead speaks for two independent dimensions. In this article, from a novel formal perspective, we revisit arguments for and against unidimensional and two-dimensional models. To determine which of these models is supported empirically, we analyzed all available studies and tested an overlooked but critical condition that would allow us to draw a definitive conclusion. Our evidence speaks against a unidimensional model in all variants.

Why is misleading partisan content believed and shared? An influential account posits that political partisanship pervasively biases reasoning, such that engaging in analytic thinking exacerbates motivated reasoning and, in turn, the acceptance of hyperpartisan content. Alternatively, it may be that susceptibility to hyperpartisan content is explained by a lack of reasoning. Across two studies using different participant pools (total N = 1,973 Americans), we had participants assess true, false, and hyperpartisan news headlines taken from social media. We found no evidence that analytic thinking was associated with judging politically consistent hyperpartisan or false headlines to be accurate and unbiased. Instead, analytic thinking was, in most cases, associated with an increased tendency to distinguish true headlines from both false and hyperpartisan headlines (and was never associated with decreased discernment). These results suggest that reasoning typically helps people differentiate between low and high quality political news, rather than facilitate belief in misleading content. Because social media play an important role in the dissemination of misinformation, we also investigated willingness to share headlines on social media. We found a similar pattern whereby analytic thinking was not generally associated with increased willingness to share hyperpartisan or false headlines. Together, these results suggest a positive role for reasoning in resisting misinformation.

We investigate the manual selection of numbers by lottery participants,with a database consisting of over 800 million selections from 118 consecutive draws of the national lottery in Israel. Our findings replicate results from prior research and introduce novel discoveries.(1) Preference for, and avoidance of, specific numbers 1 through 37 are consistent throughout all the drawings. Strong, but differing preferences are observed in the selection of the “power” number ranging from 1 to 7. (2) The number of guesses entered per draw correlates with the size of the prize, with each additional million in prize money generating 33,000 additional manual guesses. (3) Number preferences are strongly influenced by their location on the form. Numbers in the first of the four horizontal rows are consistently the most popular, while numbers in the fourth rows are consistently unpopular. (4) As the number of guesses increases, popularly chosen numbers tend to become slightly less popular, while unpopular numbers tend to become less unpopular.

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 faced with novel tasks. For each task, they were assigned a tool but also exposed to a comparison tool that was better or worse in utility (or sometimes similar in utility). In some studies, the tool comparisons were essentially social comparisons, because the tool was assigned to another person. In other studies, the tool comparisons were merely counterfactual rather than social. The studies revealed contrast effects on optimism, and the effect worked in both directions. That is, worse comparison tools boosted optimism and better tools depressed optimism. The contrast effects were observed regardless of the general type of comparison (e.g., social, counterfactual). The comparisons also influenced discrete decisions about which task to attempt (for a prize), which is an important finding for ruling out superficial scaling explanations for the contrast effects. It appears that people fail to exclude irrelevant tool-comparison information from consideration when assessing their likelihood of success on a task, resulting in biased optimism and decisions.

In two studies, we tested the power of revenge as a justification mechanism thatenables people to cheat with a clear conscience. Specifically, we explored theeffects of prior dishonesty and unfairness towards participants on theirsubsequent moral behavior, as well as the physiological arousal associated withit. To this end, we employed a two-phase procedure. In the first phase,participants played one round of a bargaining game (the Ultimatum game in Study1 and the Dictator game in Study 2) in which we manipulated whether the playershad been treated (un)fairly and (dis)honestly by their opponent. In the secondphase, they did a perceptual task that allowed them to cheat for monetary gainat the expense of their opponent from the first phase. In Study 1, participantsalso took a lie detector test to assess whether their dishonesty in the secondphase could be detected. The behavioral results in both studies indicated thatthe opponent’s dishonesty was a stronger driver than theopponent’s unfairness for cheating as a form of retaliation. However, thephysiological arousal results suggest that feeling mistreated in general (andnot just cheated) allowed the participants to get revenge by cheating theoffender while dismissing their associated guilt feelings.

During the COVID-19 pandemic, public health guidance (e.g., regarding the use ofnon-medical masks) changed over time. Although many revisions were a result ofgains in scientific understanding, we nonetheless hypothesized that makingchanges in guidance salient would negatively affect evaluations of experts andhealth-protective intentions. In Study 1 (N = 300), wedemonstrate that describing COVID-19 guidance in terms of inconsistency (versusconsistency) leads people to perceive scientists and public health authoritiesless favorably (e.g., as less expert). For participants in Canada(n = 190), though not the U.S. (n = 110),making guidance change salient also reduced intentions to download a contacttracing app. In Study 2 (N = 1399), we show that a briefforewarning intervention mitigates detrimental effects of changes in guidance.In the absence of forewarning, emphasizing inconsistency harmed judgments ofpublic health authorities and reduced health-protective intentions, butforewarning eliminated this effect.

In this paper, we examined two pairs of datasets from selected Nigerian lottery games to determine players’ number preferences. Data explorations were conducted in the first pair of datasets to identify patterns in players’ choices of lottery numbers. The question whether players preferred number combinations that are well-spread out regardless of their true theoretical probabilities was examined in the second pair. In the first pair of datasets, we find that most players have a preference for small numbers especially 1 and 9. They also prefer numbers with repeated digits and tend to avoid multiples of 7 and numbers containing 7 (except 7 and 77). The most popular numbers are 90 and 1. In the second pair of the datasets, more than 50% of the players preferred selecting well-spread out number combinations than expected by chance.

Understanding how sustainable preference change can be achieved is of both scientific and practical importance. Recent work shows that merely responding or not responding to objects during go/no-go training can influence preferences for these objects right after the training, when people choose with a time limit. Here we examined whether and how such immediate preference change in fast choices can affect choices without time limit one week later. In two preregistered experiments, participants responded to go food items and withheld responses toward no-go food items during a go/no-go training. Immediately after the training, they made consumption choices for half of the items (with a time limit in Experiment 1; without time limit in Experiment 2). One week later, participants chose again (without time limit in both experiments). Half of the choices had been presented immediately after the training (repeated choices), while the other half had not (new choices). Participants preferred go over no-go items both immediately after the training and one week later. Furthermore, the effect was observed for both repeated and new choices after one week, revealing a direct effect of mere (non)responses on preferences one week later. Exploratory analyses revealed that the effect after one week is related to the memory of stimulus-response contingencies immediately after the training, and this memory is impaired by making choices. These findings show mere action versus inaction can directly induce preference change that lasts for at least one week, and memory of stimulus-response contingencies may play a crucial role in this effect.

The interplay between intuitive and deliberative processing is known to be important for human decision making. As independent modes, intuitive processes can take on many forms from associative to constructive, while deliberative processes often rely on some notion of decision theoretic rationality or pattern matching. Dual process models attempt to unify these two modes based on parallel constraint networks or on socially or emotionally oriented adjustments to utility functions. This paper presents a new kind of dual process model that unifies decision theoretic deliberative reasoning with intuitive reasoning based on shared cultural affective meanings in a single Bayesian sequential model. Agents constructed according to this unified model are motivated by a combination of affective alignment (intuitive) and decision theoretic reasoning (deliberative), trading the two off as a function of the uncertainty or unpredictability of the situation. The model also provides a theoretical bridge between decision-making research and sociological symbolic interactionism. Starting with a high-level view of existing models, we advance Bayesian Affect Control Theory (BayesACT) as a promising new type of dual process model that explicitly and optimally (in the Bayesian sense) trades off motivation, action, beliefs and utility. We demonstrate a key component of the model as being sufficient to account for some aspects of classic cognitive biases about fairness and dissonance, and outline how this new theory relates to parallel constraint satisfaction models.

Messaging applications are changing the communication landscape in emergingcountries. While offering speed and affordability, these solutions have alsoopened the way for the spread of misinformation. Aiming to better understand thedynamics of COVID-19 as infodemic, we asked Brazilian participants (n=1007) toreport the perceived accuracy of 20 messages (10 true and 10 false). Eachmessage was randomly presented within five fictitious WhatsApp group chats ofvarying political orientation. Correlational analyses revealed that right-wingparticipants had lower levels of truth discernment as did those with greatertrust in social media as a reliable source of coronavirus information.Conversely, open-minded thinking about evidence and trust in the WHO andtraditional media was positively associated with truth discernment. Familiaritywith the content consistently increased perceived truthness for both true andfalse messages. Results point to the nefarious effects of COVID-19politicization and underline the importance of promoting the ability torecognize and value new evidence as well as enhancing trust in internationalagencies and traditional media.

A standard way to elicit expectations asks for the percentage chance an event will occur. Previous research demonstrates noise in reported percentages. The current research models a bias; a five percentage point change in reported probabilities implies a larger change in beliefs at certain points in the probability distribution. One contribution of my model is that it can parse bias in beliefs from biases in reports. I reconsider age and gender differences in Subjective Survival Probabilities (SSPs). These are generally interpreted as differences in survival beliefs, e.g., that males are more optimistic than females and older respondents are more optimistic than younger respondents. These demographic differences (in the English Longitudinal Study of Ageing) can be entirely explained by reporting bias. Older respondents are no more optimistic than younger respondents and males are no more optimistic than females. Similarly, in forecasting, information is obscured by taking reported percentages at face value. Accounting for reporting bias thus better exploits the private information contained in reports. Relative to a face-value specification, a specification that does this delivers improved forecasts of mortality events, raising the pseudo R-squared from less than 3 percent to over 6 percent.

People do not save enough for retirement and this can have serious repercussions on their well-being. We tested an intervention in a large field study (N = 20,507) with the goal of nudging a population of freelance workers to save more for the future. First, we changed the default from the earlier contribution rate of 10% to a contribution rate of 20%, but left people free to choose how much they wanted to contribute. Second, those who reduced their contribution were reminded that they would receive a lower pension as a result. Third, we informed people about how much tax they would save as a result of their contribution. This nudging intervention proved to be a cost-effective, yet powerful way to remind people about the long-term implications of their savings decisions. It was also successful at counteracting the temptation to keep as much money as possible for present consumption while losing out on the long run. Overall, we were able to increase cash flow to the fund by more than eight million Euros (in addition to the roughly 50 million collected in the previous year), with an almost seven-fold increase in the number of people who chose to contribute more than the minimum.