Jan Willem van Prooijen

Vrije Universiteit Amsterdam | VU · Department of Social and Organisational Psychology

Scholars and policy‐makers are increasingly concerned with the detrimental effects of conspiracy theories. Yet, it remains unclear whether conspiracy beliefs actually pose a threat to democracy by rendering people less supportive of democratic governance. Three studies suggest that conspiracy theories may incite support for autocratic regimes. A fi...

Conspiracy theories arise during important societal and political events, with negative consequences. Yet, conspiracy theories remain to be investigated in the context of sporting tournaments, in spite of the importance of such events in contemporary societies. During the 2018 FIFA World Cup, conspiracy theories alleging that the newly introduced v...

Moral character is widely expected to lead to moral judgments and practices. However, such expectations are often breached, especially when moral character is measured by self-report. We propose that because self-reported moral character partly reflects a desire to appear good, people who self-report a strong moral character will show moral harshne...

Corruption is a pervasive phenomenon that affects the quality of institutions, undermines economic growth and exacerbates inequalities around the globe. Here we tested whether perceiving representatives of institutions as corrupt undermines trust and subsequent prosocial behaviour among strangers. We developed an experimental game paradigm modellin...

Online communities play an important role in spreading public discontent and could contribute to polarization. This study focuses on anti-vaccination views in the Netherlands, which have intensified during the COVID-19 pandemic. We examined the structure and development of five Dutch anti-vaccination Telegram groups and studied their interactivity...

In recent years, it has been argued that conspiracy beliefs and populist attitudes go hand in hand. Despite their theoretical and empirical similarities, it remains unclear why these constructs are so closely associated. Across three studies, we examined the processes underlying the relationship between belief in conspiracy theories and populist at...

Personality traits are robust predictors of the likelihood of involvement in criminal behaviour, but how such traits predict behaviour while committing a crime is unclear. This study investigates associations between HEXACO personality traits and burglars' scouting process, as well as how burglars differ in this respect from non-offenders due to th...

Do populist attitudes predict a growth in feelings of hate? Or does experiencing hate predict a growth in populist attitudes? Previous research has not yet examined the relation between populist attitudes and hate over time. We conducted a two-wave study with a Dutch adult sample in the Netherlands, to examine the time-extended associations between...

Background Little is known about how conspiracy beliefs and health responses are interrelated over time during the course of the coronavirus disease 2019 (Covid-19) pandemic. This longitudinal study tested two contrasting, but not mutually exclusive, hypotheses through cross-lagged modeling. First, based on the consequential nature of conspiracy be...

Fortune telling is a widespread phenomenon, yet little is known about the extent to which people are affected by it—including those who consider themselves non-believers. The present research has investigated the power of a positive fortune telling outcome (vs. neutral vs. negative) on people’s financial risk taking. In two online experiments ( n 1...

It is widely documented that third parties punish norm violations, even at a substantial cost to themselves. However, little is known about how third-party punishment occurs in groups consisting of members that differ in status. Having a higher-status member promotes norm enforcement and group efficiency, but also poses threats to collective goods...

Conspiracy beliefs have been studied mostly through cross‐sectional designs. We conducted a five‐wave longitudinal study (N = 376; two waves before and three waves after the 2020 American presidential elections) to examine if the election results influenced specific conspiracy beliefs and conspiracy mentality, and whether effects differ between ele...

The Big Two theoretical framework suggests that two traits, namely morality and competence, govern social judgments of individuals and that morality shows a primacy effect over competence because it has more diagnostic value. In this study we tested the primacy effect of morality in the workplace by examining how instrumental or relational goals of...

At the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions. In this study, we applied ma...

In the present research, we examine how power and group membership of an offender influence observers’ motives for punishment. As compared to powerless offenders, powerful offenders should elicit a stronger motivation of an observer to incapacitate them and protect society (i.e., utilitarian punishment motivation). Moreover, demonization of the off...

Many people believe conspiracy theories, even though such beliefs are harmful to themselves and their social environment. What is the appeal of conspiracy theories? In this contribution I propose that conspiracy theories have psychological benefits by imbuing perceiver’s worldview with meaning and purpose in a rewarding manner. Conspiracy theories...

This study examines the deterrent effects of neighbourhood watch signs and police signs as measures of symbolic guardianship on burglars versus non-offenders. In a virtual reality experiment, 181 burglars and 172 non-offenders scouted a virtual neighbourhood and were exposed to neighbourhood watch signs and/or signs suggesting police surveillance i...

This study aimed to replicate the intuitive retributivism hypothesis, according to which people’s punitive sentiments are predominantly driven by retributive concerns. Contrary to prior research that focuses on how people punish offenders, this study investigated how people punish individuals suspected of immoralities. Moreover, we manipulated a su...

Populist movements typically endorse a pessimistic view that blames the “elites” for societal problems. Why is this populist worldview so appealing to many citizens? We propose that populism is associated with nostalgia: A bittersweet feeling defined as a sentimental longing for a better past. We tested this idea in three preregistered studies. Stu...

Conspiracy theories are widespread and have a profound impact on society. The present contribution proposes that conspiracy theories are explanatory narratives that necessarily contain justice judgments, as they include attributions of blame and accusations of unethical or criminal conduct. Conspiratorial narratives also are mental simulations, how...

People differ in their general tendency to endorse conspiracy theories (that is, conspiracy mentality). Previous research yielded inconsistent findings on the relationship between conspiracy mentality and political orientation, showing a greater conspiracy mentality either among the political right (a linear relation) or amongst both the left and r...

In the present research, we examine how culture influences individuals' reactions to financial offenders. We hypothesized that horizontal individualists deploy increased active reactions (i.e., punishment-oriented) whereas vertical collectivists deploy increased passive reactions (i.e., condemning beliefs) to financial offenders. Moreover, we hypot...

Status can be seen as power over valued resources, or as prestige that lies in the eyes of the beholder. In the present research we examine how power versus prestige influence observers' punishing motives. Possession of power implies the capacity to harm and elicits threat, and therefore should trigger stronger incapacitative motives for punishing...

Status can be seen as power over valued resources or as prestige that lies in the eyes of the beholder. In the present research, we examine how power versus prestige influence observers’ punishing motives. Possession of power implies the capacity to harm and elicits threat and therefore should trigger stronger incapacitative motives for punishing a...

Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and str...

The present research examines the relationship between populist attitudes—that construe society as a struggle between the “corrupt elites” versus the “noble people”—and beliefs in unsubstantiated epistemic claims. We specifically sought to assess the often assumed link between conspiracy beliefs and populist attitudes; moreover, we examined if popu...

Is hate fundamentally different from other negative emotions? Despite a fair amount of theorizing about hate, there is little empirical evidence that helps to answer this basic question. The present research examines how people construe interpersonal and intergroup hate and provides an empirical analysis of how hate is conceptually different from d...

Using the label “conspiracy theory” is widely perceived to be a way of discrediting wild ideas and unsubstantiated claims. However, prior research suggests that labelling statements as conspiracy theories does not reduce people’s belief in them. In four studies, we probed this effect further, and tested the alternative hypothesis that the label “co...

Objectives This study investigates the deterrent effects of incremental levels of guardianship on residential burglary and assesses how burglars differ from non-burglars in terms of their perceptions of opportunities for burglary.Methods In a virtual reality experiment, 181 incarcerated burglars and 172 non-burglars (university students) were taske...

The Covid-19 pandemic has inspired many conspiracy theories, which are associated with detrimental health beliefs and behaviors (e.g. reduced physical distancing; decreased vaccination intentions). We propose a previously unrecognized mediator of these relationships: A self-perceived likelihood to already have experienced a Covid-19 infection. Resu...

Background Conspiracy beliefs are associated with detrimental health attitudes during the coronavirus disease 2019 (Covid-19) pandemic. Most prior research on these issues was cross-sectional, however, and restricted to attitudes or behavioral intentions. The current research was designed to examine to what extent conspiracy beliefs predict health...

People often say one thing while doing another, and are therefore criticized as hypocrites. Despite the widespread criticism of hypocrites, relatively less is known about factors that influence moral judgment of hypocrisy. In particular, why are some word-deed inconsistencies condemned more harshly than others? The current research focuses on word-...

Analytic thinking has been put forth as one of the processes through which people may become atheists. According to this view, people who are more (vs. less) analytically inclined should be more likely to reject the existence of deities because they rely less on the various intuitive cognitive processes that support supernatural beliefs. Consistent...

This paper seeks to understand the association between ratees’ relational justice perceptions and their feedback acceptance, both directly and through leader–member exchange (LMX). The paper also examines the moderated mediation effect of supervisory trust. The paper presents the findings of two studies. Study 1 utilized two data sets collected thr...

Although an increasing volume of research has identified several negative sociopolitical attitudes as correlates of conspiracy theories, to date it remains unclear whether belief in conspiracy theories is necessarily in conflict with support for democratic governance. In this contribution, we integrate previous findings suggesting inconsistent rela...

Many citizens around the globe believe conspiracy theories. Why are conspiracy theories so appealing? Here, we propose that conspiracy theories elicit intense emotions independent of emotional valence. People therefore find conspiracy theories entertaining – that is, narratives that people perceive as interesting, exciting, and attention‐grabbing –...

Many citizens distrust powerful societal institutions, and hold conspiracy theories about them. What are the implications of this suspicion of institutions for people’s social relationships? The current paper proposes that institutions have at least two functions to regulate citizens’ social relationships: Providing people with a sense of safety, a...

Politicians are influential both in directing policies about refugees and in framing public discourse about them. However, unlike other host country residents, politicians' attitudes towards refugees and integration are remarkably understudied. We therefore examine similarities and differences between politicians' attitudes towards refugee integrat...

Status holders across societies often take moral initiatives to navigate group practices toward collective goods; however, little is known about how different societies (e.g., the US versus China) evaluate high- (vs. low-) status holders’ transgressions of preached morals. Two pre-registered studies (total N = 1,374) examined how status information...

Research on the transgression credit shows that groups may sometimes turn a blind eye to ingroup leaders who transgress moral norms. Although there is substantial research investigating the underlying criteria of what makes a “good” leader, research often neglects to investigate the role of followers in leader‐group dynamics. In this paper, we offe...

During the COVID-19 pandemic, many people have endorsed conspiracy theories about foreign governments yet shown increased trust and support for their own government. Whether there is a potential correlation between these social phenomena and the psychological mechanisms behind them is still unclear. Integrating insights from the existential threat...

Moral character is widely believed to guide a moral and prosocial life, navigating individuals through decisions about right or wrong. People with a strong moral character therefore may not be expected to behave hypocritically, by imposing stringent moral standards on others but not on themselves. But from an evolutionary perspective, moral charact...

Research suggests that belief in conspiracy theories (CT) stems from basic psychological mechanisms and is linked to other belief systems (e.g. religious beliefs). While previous research has extensively examined individual and contextual variables associated with CT beliefs, it has not yet investigated the role of culture. In the current research,...

Previous research suggests that political extremists have stronger convictions in their beliefs than moderates. The present research examines the relationship between political extremism and belief stability, defined as the extent to which people change their ideological beliefs over time. Studies 1 (N = 397) and 2 (N = 291) revealed that participa...

Research suggests that belief in conspiracy theories (CT) stems from basic psychological mechanisms and is linked to other belief systems (e.g. religious beliefs). While previous research has extensively examined individual and contextual variables associated with CT beliefs, it has not yet investigated the role of culture. In the current research,...

Interpersonal trust is an important source of social and economic development. Over decades, researchers debated the question whether and how public institutions influence interpersonal trust, making this relationship a much-discussed issue for scientific debate. However, experimental and behavioral data and insights on this relationship and the un...

Although conspiracy theories are ubiquitous across times and cultures, research has not investigated how cultural dimensions may predict conspiracy beliefs. The present research examined intergroup conspiracy beliefs in United States and Chinese samples at the peak of the trade war. In two studies (one pre‐registered; total N = 1,092), we asked US...

In this chapter, we presents the results from a multi-method study in the Netherlands into the role of socio-economic and psychological factors underlying terrorism involvement. Building on theories and findings of previous researchers in the field, we present a descriptive model of terrorism that categorizes distal and proximal ‘threat triggers’....

People can polarize into various ideologies, including tendencies towards political left- and right-wing extremism, and religious fundamentalism. Here we compare polarization in these different ideologies in a US online sample (N = 424). Building on significance quest theory, we specifically investigate how individual tendencies towards political e...

Purpose This study seeks to examine the links between employee agreeableness, group performance, and peers' perceptions of threat of retaliation, through relationship conflict. Design/methodology/approach In a laboratory setting, 42 groups of undergraduate students ( N = 182) from a Pakistani university were assigned to group projects to be comple...

Although many studies have investigated the backgrounds of people who went to Syria to join jihadist groups, much remains unclear about the underlying radicalisation processes. Many authors have noted that radicalisation and terrorism are associated with involvement in crime (the crime-terror nexus), in particular with membership of delinquent grou...

People endorse conspiracy theories particularly when they experience existential threat, that is, feelings of anxiety or uncertainty often because of distressing societal events. At the same time, such feelings also often lead people to support groups frequently implicated in conspiracy theories (e.g., the government). The present contribution aims...

When people are transgressed against, they are usually motivated to restore personal power that was threatened by the transgression. We argue and test the new idea that while revenge and forgiveness responses are typically seen as opposites, both may be empowering, depending on the offender’s intent to harm. Across two studies, one experimental (N...

In the present research, we examined a discrepancy between people's beliefs about, versus punitive reactions towards, offenders. Particularly, appraisals of offenders along the dimension of communion (i.e., being friendly or trustworthy) should primarily affect people's beliefs about them, as reflected in demonizing and conspiracy theories, and to...

People often vote against the political establishment, as underscored by “Brexit” and the Trump election. The current contribution proposes that overclaiming one’s own knowledge predicts anti-establishment voting. We tested this idea in the context of a Dutch referendum on a European Union treaty with a clear pro- versus anti-establishment voting o...

In dit onderzoek is onderzocht welke relatie er bestaat tussen problematische jeugdgroepen in Nederland en radicalisering.

People often consider themselves as more moral than average others (i.e., moral superiority) and present themselves as more moral than they actually are (i.e., moral hypocrisy). We examined whether feelings of moral superiority—as a manifestation of self-enhancement motives—motivates people’s hypocritical behavior, that is, their discrepant moral p...

The recent rise in controversial politicians has garnered substantial interest in the assessment of their personality. Observer ratings of politicians’ personality, however, may suffer from evaluative and value-related biases. Evaluative biases are likely to differentially affect personality ratings of preferred and non-preferred politicians, where...

Institutional and political distrust are often associated with the improved electoral performance of extremist parties. This study analyses to what extent political distrust and Euroscepticism are associated with extreme left and right ideological positions. We specifically examine voters in the Netherlands – a country with wide array of political...

Research in behavioural ethics repeatedly emphasizes the importance of others for people’s decisions to break ethical rules. Yet, in most lab experiments participants faced ethical dilemmas in full privacy settings. We conducted three experiments in which we compare such private set-ups to situations in which a second person is co-present in the la...

Based on Terror Management Theory (TMT), we suggest that spirituality and prosocial attitudes toward money have a similar defensive function in resisting existential anxiety. In mortality salient (MS) situations, both spirituality and prosocial money attitudes afford symbolic immortality by self-transcendent connections. In four studies, we found t...

In this article, we examine psychological features of extreme political ideologies. In what ways are political left- and right-wing extremists similar to one another and different from moderates? We propose and review four interrelated propositions that explain adherence to extreme political ideologies from a psychological perspective. We argue tha...

Conspiracy theories can be harmful for public health, global warming, safety, conflict, and political polarization. What interventions help reduce the appeal of conspiracy theories? It is well-known that conspiracy theories flourish among citizens who feel powerless and out of control, however I argue that the opposite is also true: that feeling em...

Belief in conspiracy theories—such as that the 9/11 terrorist attacks were an inside job or that the pharmaceutical industry deliberately spreads diseases—is a widespread and culturally universal phenomenon. Why do so many people around the globe believe conspiracy theories, and why are they so influential? Previous research focused on the proximat...

In this introduction to the EJSP Special Issue on conspiracy theories as a social psychological phenomenon, we describe how this emerging research domain has developed over the past decade and distill four basic principles that characterize belief in conspiracy theories. Specifically, conspiracy theories are consequential as they have a real impact...

In the present study, we tested whether Muslim minority members are more susceptible to conspiracy theories than majority members in the Netherlands. We examined conspiracy theories that are relevant (portraying the Muslim community as victim or Jewish people as perpetrators) and irrelevant for participants' Muslim identity (about the 2007 financia...

Most moral demands indeed are externally imposed, as violations are subject to social condemnation. While in modern society objectified moral demands may serve as a cue for desirable interaction partners, human morality evolved in small tribes that offered little choice regarding with whom to cooperate. Instead, it was adaptive to objectify moral d...

Because punishments are expected to give offenders what they deserve proportionally to the severity of their offenses, the punishment of an entire group because of the misdeed of a few of its members is generally considered as unfair. Group entitativity might increase support for such collective punishment, because members of highly entitative grou...

Mediation analyses for other variables measured in all experiments. (DOC)

Current study has two main goals. First, it proposes the threat model of terrorism to investigate socio-economic, cultural and psychological determinants of terrorism. Second, it tests the threat model on different sets of quantitative data, such as police data on suspects of terrorism, register data on changes in socio-economic circumstance, as we...