Pre-registered Online Experiment Research Articles

From Storytelling to Facebook

Cultural evolution researchers use transmission chain experiments to investigate which content is more likely to survive when transmitted from one individual to another. These experiments resemble oral storytelling, wherein individuals need to understand, memorize, and reproduce the content. However, prominent contemporary forms of cultural transmission—think an online sharing—only involve the willingness to transmit the content. Here I present two fully preregistered online experiments that explicitly investigated the differences between these two modalities of transmission. The first experiment (N = 1,080 participants) examined whether negative content, information eliciting disgust, and threat-related information were better transmitted than their neutral counterpart in a traditional transmission chain setup. The second experiment (N = 1,200 participants) used the same material, but participants were asked whether or not they would share the content in two conditions: in a large anonymous social network or with their friends, in their favorite social network. Negative content was both better transmitted in transmission chain experiments and shared more than its neutral counterpart. Threat-related information was successful in transmission chain experiments but not when sharing, and finally, information eliciting disgust was not advantaged in either. Overall, the results present a composite picture, suggesting that the interactions between the specific content and the medium of transmission are important and, possibly, that content biases are stronger when memorization and reproduction are involved in the transmission—as in oral transmission—than when they are not—as in online sharing. Negative content seems to be reliably favored in both modalities of transmission.

Judging accidental harm: Reasoning style modulates the weight of intention and harm severity.

When judging a perpetrator who harmed someone accidentally, humans rely on distinct information pertaining to the perpetrator and victim. The present study investigates how reasoning style modulates the contribution of the victim's harm and the perpetrator's intention to third-party judgement of accidental harm. In two pre-registered online experiments, we simultaneously manipulated harm severity and the perpetrator's intention. Participants completed reasoning measures as well as a moral judgement task consisting of short narratives which depicted the interaction between a perpetrator and a victim. In experiment 1, we manipulated the perpetrator's intent to harm (accidental versus intentional harm) and the victim's harm (mild versus severe harm). In experiment 2, we aimed to manipulate intent in accidental harm scenarios exclusively, using positive or neutral intents and manipulating harm severity (mild versus severe harm). As expected, intent and harm severity moderated participants' moral judgement of acceptability, punishment, and blame. Most importantly, in both experiments, the perpetrator's intent not only interacted with the outcome severity but also polarised moral judgements in participants with a more deliberative reasoning style. While moral judgements of more intuitive reasoners were less sensitive to intent, more deliberative reasoners were more forgiving of accidental harm, especially following mild harm. These findings extend previous studies by showing that reasoning style interacts with intent and harm severity to shape moral judgement of accidents.

Effective uncertainty visualization for aftershock forecast maps

Abstract. Earthquake models can produce aftershock forecasts, which have recently been released to lay audiences. While visualization literature suggests that displaying forecast uncertainty can improve how forecast maps are used, research on uncertainty visualization is missing from earthquake science. We designed a pre-registered online experiment to test the effectiveness of three visualization techniques for displaying aftershock forecast maps and their uncertainty. These maps showed the forecasted number of aftershocks at each location for a week following a hypothetical mainshock, along with the uncertainty around each location's forecast. Three different uncertainty visualizations were produced: (1) forecast and uncertainty maps adjacent to one another; (2) the forecast map depicted in a color scheme, with the uncertainty shown by the transparency of the color; and (3) two maps that showed the lower and upper bounds of the forecast distribution at each location. We compared the three uncertainty visualizations using tasks that were specifically designed to address broadly applicable and user-generated communication goals. We compared task responses between participants using uncertainty visualizations and using the forecast map shown without its uncertainty (the current practice). Participants completed two map-reading tasks that targeted several dimensions of the readability of uncertainty visualizations. Participants then performed a Comparative Judgment task, which demonstrated whether a visualization was successful in reaching two key communication goals: indicating where many aftershocks and no aftershocks are likely (sure bets) and where the forecast is low but the uncertainty is high enough to imply potential risk (surprises). All visualizations performed equally well in the goal of communicating sure bet situations. But the visualization with lower and upper bounds was substantially better than the other designs at communicating surprises. These results have implications for the visual communication of forecast uncertainty both within and beyond earthquake science.

Lateral reading and monetary incentives to spot disinformation about science

Disinformation about science can impose enormous economic and public health burdens. A recently proposed strategy to help online users recognise false content is to follow the techniques of professional fact checkers, such as looking for information on other websites (lateral reading) and looking beyond the first results suggested by search engines (click restraint). In two preregistered online experiments (N = 5387), we simulated a social media environment and tested two interventions, one in the form of a pop-up meant to advise participants to follow such techniques, the other based on monetary incentives. We measured participants’ ability to identify whether information was scientifically valid or invalid. Analysis of participants’ search style reveals that both monetary incentives and pop-up increased the use of fact-checking strategies. Monetary incentives were overall effective in increasing accuracy, whereas the pop-up worked when the source of information was unknown. Pop-up and incentives, when used together, produced a cumulative effect on accuracy. We suggest that monetary incentives enhance content relevance, and could be combined with fact-checking techniques to counteract disinformation.

Fostering compliance with physical distancing by interactive feedback in the context of the COVID-19 pandemic: A web-based randomized controlled trial

BackgroundTo slow down the spread of COVID-19, the observance of basic hygiene measures, and physical distancing is recommended. Initial findings suggest that physical distancing in particular can prevent the spread of COVID-19. ObjectivesTo investigate how information to prevent the spread of infectious diseases should be presented to increase willingness to comply with preventive measures. MethodsIn a preregistered online experiment, 817 subjects were presented with either interactively controllable graphics on the spread of COVID-19 and information that enable them to recognize how much the spread of COVID-19 is reduced by physical distancing (experimental group) or text-based information about quantitative evidence (control group). It was hypothesized that participants receiving interactive information on the prevention of COVID-19 infections show a significantly higher willingness to comply with future containment measures than participants reading the text-based information. Explorative analyses were conducted to examine whether other factors influence compliance. ResultsAs predicted, we found a small effect (d = 0.22, 95% CI: 0.11; 0.23, p < .001) for the tested intervention. The exploratory analysis suggests a decline in compliance later in the study (r = −0.10, 95% CI: −0.15; −0.07). Another significant predictor of change in compliance was health-related anxiety, but the effect was trivial. ConclusionsWhen presented interactively, information on how the own behavior can help prevent infectious diseases can lead to slightly stronger changes in attitude towards behavioral prevention measures than just text-based information. Given the scalability of this simple internet-based intervention, it could play a role in fostering compliance during a pandemic within universal prevention strategies. Future work on the predictive validity of self-reported compliance and the real-world effects on the intervention is needed.

Set Size and Donation Behavior.

Choice overload is the phenomenon that increasing the number of options in an assortment makes choosing between options more difficult, sometimes leading to avoidance of making a choice. In this pre-registered online experiment (N = 501), choice overload was tested in a charitable behavior context, where participants faced a monetary donation choice. Charity organization assortment size was varied between groups, ranging between 2 and 80 options. The results indicate that there were no meaningful differences in donation likelihood between the 16 organization assortment sizes, neither for individuals with high preference certainty nor for individuals with uncertain preferences among charitable causes. Having more charitable organizations to choose from did not affect donation behavior.

Effectiveness of a Motivational Smoking Reduction Strategy Across Socioeconomic Status and Stress Levels.

Smoking consequences are seen disproportionately among low-SES smokers. We examine the self-regulatory strategy of mental contrasting with implementation intentions (MCII) as a smoking reduction tool and whether its effectiveness depends on subjective-SES. This pre-registered online experiment comprised a pre-screening, baseline survey, and follow-up. Participants reported past-week smoking, subjective-SES, perceived stress, and were randomized to an active control (n = 161) or MCII condition (n = 164). Data were collected via MTurk, during the U.S.’ initial wave of COVID-19. Participants were moderate-to-heavy smokers open to reducing or quitting. The primary outcome was self-reported smoking reduction, computed as the difference between recent smoking at baseline and follow-up. The secondary outcome was cessation, operationalized as self-reported 7-day point-prevalence abstinence at follow-up. Among those low—but not high—in subjective-SES, MCII (vs. control) improved smoking reduction by an average of 1.09 fewer cigarettes smoked per day, though this effect was not conclusive (p = 0.11). Similarly, quitting was descriptively more likely for those in the MCII than control condition, but the effect was non-significant (p = 0.11). Per an exploratory analysis, we observed that stress significantly moderated the condition effect (p = 0.01), such that MCII (vs. control) facilitated reduction among those experiencing high (p = 0.03), but not low stress (p = 0.15). Consistent with prior findings that MCII works best in vulnerable populations, MCII may be more effective for smoking reduction among high-stress than low-stress individuals. These findings contribute to growing research on income-related health disparities and smoking behavior change tools.

To disclose or not to disclose? Factors related to the willingness to disclose information to a COVID-19 tracing app

ABSTRACT Contact-tracing apps have been identified as a promising technology to curb the spread of COVID-19. To be effective, a sufficient number of individuals need to install the app and disclose information like COVID-19 infection to such an app. Yet, usage data demonstrate that a large number of app users does not disclose COVID-19 infection to the app. Hence, in two studies (overall N = 1522), we investigate factors related to individuals’ willingness to actively disclose information to such an app. In a preregistered online experiment conducted two months before the app launch onto the German market, we find that disclosure willingness increases when the app’s prosocial benefit or a social-life-enabling benefit is emphasized (vs. no benefit emphasized). In a subsequent, quota-representative survey study conducted two months after the app launch onto the German market, we adapted and extended the Technology Acceptance Model 2 (TAM2) to the context of prosocial information sharing in tracing apps. We find that the perceived prosocial benefit of the app, trust in public institutions, and fear of COVID-19 are the relevant predictors. Moreover, we demonstrate that the relation between perceived prosocial benefit and disclosure willingness is moderated by perceived ease of use. Results are discussed with regard to effective implementation and communication strategies for tracing apps, and the general role of prosocial concerns for technology usage to address major societal challenges.

Harming and Shaming through Naming: Examining Why Calling the Coronavirus the “COVID-19 Virus,” Not the “Chinese Virus,” Matters

ABSTRACT In an effort to stave off racial and geographic prejudices, The World Health Organization (WHO) has advised against naming pathogens for geographic regions. Despite this, some media reports, and prominent politicians, have persisted in calling the coronavirus the “Chinese Virus,” or some variant thereof. In this pre-registered online experiment (N = 614), we examined the effect media frames and individual factors (i.e., political affiliation and party) had on perceptions of COVID-19, prejudice against Chinese- and Asian-Americans, and attributing blame to China for the coronavirus. We found that articles that labeled the coronavirus the “Chinese Virus” (versus the “COVID-19 Virus”) were perceived less favorably by Democrats and liberals, in comparison to Republicans and conservatives, who were also more likely to express greater racial prejudice against Chinese- and Asian-Americans and to blame China for the pandemic. Findings from this study suggest that amongst a host of other variables, media framing has an effect on the public’s attitudes and feelings of blame for the pandemic.

Dynamic norms for dynamic times? An experiment on the effects of dynamic and static norms messages on COVID-19 vaccination intention

Social norms messages may motivate COVID-19 preventive behaviors, such as getting vaccinated. To date, however, the research has mainly focused on the established concept of static norms and widely ignored the potential of dynamic norms. Dynamic norms convey information about how norms are developing over time and have been shown to promote change when the behavior is not yet the majority norm. The present study investigated the potential of dynamic norms in the context of the COVID-19 vaccination campaign. It examined (a) the effects of static and dynamic norms messages on vaccination intention, (b) the mechanisms through which dynamic norms may influence vaccination intention, and (c) the potential of dynamic norms to increase vaccination intention of vaccine-hesitant people. We conducted a preregistered online experiment with three conditions (static norm, dynamic norm, control message) among people who were not yet vaccinated (N = 2,289, 16-60 years) in May 2021, during the early vaccine roll-out period for the general population in Switzerland. We found no effects of exposure to the static or dynamic norms messages on vaccination intention and no specific influence mechanisms of dynamic norms (e.g., via perceived future norm) - neither for participants who were willing to get vaccinated nor for the vaccine-hesitant group. However, further analyses showed that, among vaccine-hesitant participants, the normative perception that formerly vaccine-critical people were changing their minds was correlated with a stronger vaccination intention. We discuss potential reasons why social norms messages did not show an effect in our study and derive theoretical and practical implications.

The effect of online reputation systems on intergroup inequality

Recent studies state that online reputation systems may decrease or even eliminate intergroup inequality. These studies base their conclusion on the finding that the presence of reputation information may decrease platform users’ reliance on demographic information. However, these findings tell only part of the story of the relation between reputation systems and intergroup inequality: they overlook the problem that reputation systems help those who obtained at least one review but may negatively affect those individuals who have not participated in interactions before. This study is the first to take the endogeneity of the reputation building process into account by providing a direct test of differences in inequality between individuals of different nationality between a situation with and without a reputation system. Using a preregistered online experiment, I show that inequality between American and Indian individuals is not lower when there is a reputation system than when there is no reputation system. Moreover, emergent inequality in initial rounds affects inequality in later rounds. This implies that platforms that wish to create equal opportunities for users with different backgrounds should not only try to make their reputation system more effective, but also to reduce initial differences between individuals with different backgrounds.

The effect of financial scarcity on discretionary spending, borrowing, and investing

Past research indicates that individuals with scarce resources focus on urgent needs. We hypothesize and find that individuals with scarce financial resources have greater discretionary expenditures such that they engage in more discretionary spending, borrowing, and investing. We demonstrate that one possible explanation for why those with scarce financial resources have greater discretionary expenditures is because they have more optimistic future perceptions. We support our predictions using a sample of over 60,000 observations from a survey in rural India, two archival datasets from surveys in Italy and Germany, and two preregistered online experiments. We control, test, and rule out different alternative explanations. The results of this research extend the findings in the financial scarcity and discretionary consumption literature. Additionally, we provide actionable guidelines for managers and public policy makers on how to nudge individuals with financial scarcity.

A self-administered virtual reality intervention increases COVID-19 vaccination intention

Effective interventions for increasing people’s intention to get vaccinated are crucial for global health, especially considering COVID-19. We devised a novel intervention using virtual reality (VR) consisting of a consultation with a general practitioner for communicating the benefits of COVID-19 vaccination and, in turn, increasing the intention to get vaccinated against COVID-19.We conducted a preregistered online experiment with a 2×2 between-participant design. People with eligible VR headsets were invited to install our experimental application and complete the ten minute virtual consultation study at their own discretion. Participants were randomly assigned across two age conditions (young or old self-body) and two communication conditions (with provision of personal benefit of vaccination only, or collective and personal benefit). The primary outcome was vaccination intention (score range 1–100) measured three times: immediately before and after the study, as well as one week later.Five-hundred-and-seven adults not vaccinated against COVID-19 were recruited. Among the 282 participants with imperfect vaccination intentions (<100), the VR intervention increased pre-to-post vaccination intentions across intervention conditions (mean difference 8.6, 95% CI 6.1 to 11.1,p<0.0001). The pre-to-post difference significantly correlated with the vaccination intention one week later, ρ=0.20,p<0.0001.The VR intervention was effective in increasing COVID-19 vaccination intentions both when only personal benefits and personal and collective benefits of vaccination were communicated, with significant retention one week after the intervention. Utilizing recent evidence from health psychology and embodiment research to develop immersive environments with customized and salient communication efforts could therefore be an effective tool to complement public health campaigns.

The Effects of Situational and Individual Factors on Algorithm Acceptance in COVID-19-Related Decision-Making: A Preregistered Online Experiment

In times of the COVID-19 pandemic, difficult decisions such as the distribution of ventilators must be made. For many of these decisions, humans could team up with algorithms; however, people often prefer human decision-makers. We examined the role of situational (morality of the scenario; perspective) and individual factors (need for leadership; conventionalism) for algorithm preference in a preregistered online experiment with German adults (n = 1,127). As expected, algorithm preference was lowest in the most moral-laden scenario. The effect of perspective (i.e., decision-makers vs. decision targets) was only significant in the most moral scenario. Need for leadership predicted a stronger algorithm preference, whereas conventionalism was related to weaker algorithm preference. Exploratory analyses revealed that attitudes and knowledge also mattered, stressing the importance of individual factors.

Reactions to warnings in the climate commons

People receive daily environmental warnings about the risk of reaching critical climate tipping points leading to irreversible consequences. However, little is known about whether such warnings promote behavioral change, or how emotions underlie such responses. Here, we present two preregistered online experiments, in which group members can harvest financial resources from a common pool while risking collective over-exploitation causing an actual environmental externality. We find that warnings are effective and that the self-conscious emotion guilt consistently correlates with (Study 1) and mediates (Study 2) the effect of warnings on sustainable behavioral change. This suggest that warnings, as a lever of experienced guilt, may qualify as an effective strategy to promote cooperation in the climate commons.

Does choice change preferences? An incentivized test of the mere choice effect

Widespread evidence from psychology and neuroscience documents that previous choices unconditionally increase the later desirability of chosen objects, even if those choices were uninformative. This is problematic for economists who use choice data to estimate latent preferences, demand functions, and social welfare. The evidence on this mere choice effect, however, exhibits serious shortcomings which prevent evaluating its possible relevance for economics. In this paper, we present a novel, parsimonious experimental design to test for the economic validity of the mere choice effect addressing these shortcomings. Our design uses well-defined, monetary lotteries, all decisions are incentivized, and we effectively randomize participants’ initial choices without relying on deception. Results from a large, pre-registered online experiment find no support for the mere choice effect. Our results challenge conventional wisdom outside economics. The mere choice effect does not seem to be a concern for economics, at least in the domain of decision making under risk.

Binding moral values gain importance in the presence of close others

A key function of morality is to regulate social behavior. Research suggests moral values may be divided into two types: binding values, which govern behavior in groups, and individualizing values, which promote personal rights and freedoms. Because people tend to mentally activate concepts in situations in which they may prove useful, the importance they afford moral values may vary according to whom they are with in the moment. In particular, because binding values help regulate communal behavior, people may afford these values more importance when in the presence of close (versus distant) others. Five studies test and support this hypothesis. First, we use a custom smartphone application to repeatedly record participants’ (n = 1166) current social context and the importance they afforded moral values. Results show people rate moral values as more important when in the presence of close others, and this effect is stronger for binding than individualizing values—an effect that replicates in a large preregistered online sample (n = 2016). A lab study (n = 390) and two preregistered online experiments (n = 580 and n = 752) provide convergent evidence that people afford binding, but not individualizing, values more importance when in the real or imagined presence of close others. Our results suggest people selectively activate different moral values according to the demands of the situation, and show how the mere presence of others can affect moral thinking.

In Need of the Devil’s Advocate? The Impact of Cross-Cutting Exposure on Political Discussion

Cross-cutting exposure (i.e., the exposure to dissonant views) is a central component of political discussion among citizens. Although political discussion is a crucial form of political engagement and a well-known source of dissonance, little is known about the impact of cross-cuttingness (vs. like-mindedness; CCLM) elicited by media news on political discussion. In the present pre-registered online experiment (N = 725), news stories were manipulated to induce CCLM and investigate its positive effect on political discussion via a specific path: deliberative thinking and the repertoire of arguments. Although no total effect of CCLM on participating in a political discussion (operationalized as discussion intent) was found, a structural equation model showed specific indirect positive effects via our hypothesized paths. Our study therefore lends support to the positive democratic implication of cross-cutting exposure. Data and material are publicly available via https://osf.io/cpnzy/.

The role of orthographic neighbourhood effects in lateralized lexical decision: a replication study and meta-analysis.

The effect of orthographic neighbourhood size (N) on lexical decision reaction time differs when words are presented in the left or right visual fields. Evidence suggests a facilitatory N effect (i.e., faster reaction times for words with larger neighbourhoods) in the left visual field. However, the N effect in the right visual field remains controversial: it may have a weaker facilitative role or it may even be inhibitory. In a pre-registered online experiment, we replicated the interaction between N and visual field and provided support for an inhibitory N effect in the right visual field. We subsequently conducted a pre-registered systematic review and meta-analysis to synthesise the available evidence and determine the direction of N effects across visual fields. Based on the evidence, it would seem the effect is inhibitory in the right visual field. Furthermore, the size of the N effect is considerably smaller in the right visual field. Both studies revealed considerable heterogeneity between participants and studies, and we consider the implications of this for future work.

Humans rely more on algorithms than social influence as a task becomes more difficult

Algorithms have begun to encroach on tasks traditionally reserved for human judgment and are increasingly capable of performing well in novel, difficult tasks. At the same time, social influence, through social media, online reviews, or personal networks, is one of the most potent forces affecting individual decision-making. In three preregistered online experiments, we found that people rely more on algorithmic advice relative to social influence as tasks become more difficult. All three experiments focused on an intellective task with a correct answer and found that subjects relied more on algorithmic advice as difficulty increased. This effect persisted even after controlling for the quality of the advice, the numeracy and accuracy of the subjects, and whether subjects were exposed to only one source of advice, or both sources. Subjects also tended to more strongly disregard inaccurate advice labeled as algorithmic compared to equally inaccurate advice labeled as coming from a crowd of peers.