Jay Joseph Van Bavel’s research while affiliated with New York University and other places

There is considerable debate over whether and how social media contributes to polarization. In a correlational study (n1 = 1,447) and two digital field experiments (n2 = 494, n3 = 1,133), we examined whether (un)following hyperpartisan social media influencers contributes to polarization and misinformation sharing. We found that incentivizing Twitter/X users to unfollow hyperpartisan social media influencers improved feelings toward the out-party by 23.5% compared to the control group, with effects persisting for at least six months. Unfollowing also led participants to engage with more accurate news and increased satisfaction with their Twitter/X feeds—without reducing engagement. This study demonstrates the long-term causal impact of exposure to hyperpartisan influencers. Moreover, unlike other social media reduction interventions, unfollowing is a targeted approach: like a scalpel, it surgically removes a few harmful parts of one’s feed, allowing the beneficial aspects to remain.

Climate change is currently one of humanity’s greatest threats. To help scholars understand the psychology of climate change, we conducted an online quasi-experimental survey on 59,508 participants from 63 countries (collected between July 2022 and July 2023). In a between-subjects design, we tested 11 interventions designed to promote climate change mitigation across four outcomes: climate change belief, support for climate policies, willingness to share information on social media, and performance on an effortful pro-environmental behavioural task. Participants also reported their demographic information (e.g., age, gender) and several other independent variables (e.g., political orientation, perceptions about the scientific consensus). In the no-intervention control group, we also measured important additional variables, such as environmentalist identity and trust in climate science. We report the collaboration procedure, study design, raw and cleaned data, all survey materials, relevant analysis scripts, and data visualisations. This dataset can be used to further the understanding of psychological, demographic, and national-level factors related to individual-level climate action and how these differ across countries.

We used machine learning to extract unique insights from a recent dataset across 55 countries (N = 4,635). The current analysis identifies the most important individual-level and nation-level predictors of climate-friendly beliefs and behaviors. Interpretable machine learning ranked 19 variables by importance for predicting climate change belief, policy support, willingness to share climate change information on social media, and a pro-environmental behavior task. We find notable differences in explained variance per outcome (e.g. 57% for climate change belief vs 10% for the pro-environmental behavior). Most predictors show divergent patterns, predicting some but not all outcomes or even having opposite effects. However, four consistent predictors were identified including Human Development Index, environmental identity, trust in climate science, and internal environmental motivation, highlighting the importance of fostering environmental identities, safeguarding trust in science, and better understanding the impact of such individual and nation-level factors in this space

Politicians invest heavily in social media to amplify narratives about their nations, but the effectiveness of such approaches remains unclear. Analyzing 758,222 posts from US and UK politicians on X (formerly Twitter), we found that right-wing politicians’ posts portraying the nation as exceptional and entitled (defensive identity rhetoric) received 42% more likes and 34% more reposts than their other posts. Left-wing politicians did not enjoy similar benefits online, and Democrats who used more defensive rhetoric (+1SD) in their posts before an election received a 42% smaller vote share. Defensive rhetoric did not hamper the electoral success of Republicans. Posts highlighting national pride and attachment (positive identity rhetoric) benefitted both sides. They received 27% more likes than other posts and politicians who used more positive identity rhetoric (+1SD) before an election received a 16% greater vote share. The research establishes a link between identity rhetoric, online attention, and electoral success.

Although morality is often characterized as a set of stable values that are deeply held, we argue that moral expressions are highly malleable and sensitive to social norms. For instance, norms can either lead people to exaggerate their expressions of morality (such as on social media) or restrain them (such as in professional settings). In this paper, we discuss why moral expressions are subject to social influence by considering two goals that govern social influence: affiliation goals (the desire to affiliate with one’s group) and accuracy goals (the desire to be accurate in ambiguous situations). Different from other domains of social influence, we argue that moral expressions often satisfy both affiliation goals (“I want to fit in with the group”) and accuracy goals (“I want to do the right thing”). As such, the fundamental question governing moral expressions is: “what does my group consider moral?” We argue that this central consideration achieves both goals underlying social influence and drives moral expressions. We outline the ways in which social influence shapes moral expressions, from unconsciously copying others’ behavior to expressing outrage to gain status within the group. Finally, we describe when the same goals can result in different behaviors, highlighting how context-specific norms can encourage (or discourage) moral expressions. We explain how this framework will be helpful in understanding how identity, norms, and social contexts shape moral expressions.

A major barrier to climate change mitigation is the political polarization of climate change beliefs. In a global experiment conducted in 60 countries (N = 51,224), we assess the differential impact of eleven climate interventions across the ideological divide. At baseline, we find political polarization of climate change beliefs and policy support globally, with people who reported being liberal believing and supporting climate policy more than those who reported being conservative (Cohen’s d = 0.35 and 0.27, respectively). However, we find no evidence for a statistically significant difference between these groups in their engagement in a behavioral tree planting task. This conceptual-behavioral polarization incongruence results from self-identified conservatives acting despite not believing, rather than self-identified liberals not acting on their beliefs. We also find three interventions (emphasizing effective collective actions, writing a letter to a future generation member, and writing a letter from the future self) boost climate beliefs and policy support across the ideological spectrum, and one intervention (emphasizing scientific consensus) stimulates the climate action of people identifying as liberal. None of the interventions tested show evidence for a statistically significant boost in climate action for self-identified conservatives. We discuss implications for practitioners deploying targeted climate interventions.

Norms on social media tend to be more extreme than offline norms–creating false perceptions of norms. The current paper explains how modern technology interacts with human psychology to create a funhouse mirror version of social norms. Specifically, we integrate research from political science, psychology, and cognitive science to explain how online environments become saturated with false norms, who is misrepresented online, what happens when online norms deviate from offline norms, where people are affected online, and why expressions are more extreme online. We provide a framework for understanding and correcting for the distortions in our perceptions of social norms that are created by social media platforms. We argue the funhouse mirror nature of social media can be pernicious for individuals and society by increasing pluralistic ignorance and false polarization.

The tendency for people to consider themselves morally good while behaving selfishly is known as “moral hypocrisy.” Influential work by Valdesolo & DeSteno (2007) found evidence for intergroup moral hypocrisy, such that people are more forgiving of transgressions when they were committed by an in-group member than an out-group member. We conducted two experiments to examine moral hypocrisy and group membership in an online paradigm with Prolific Workers from the US: a direct replication of the original work with minimal groups (N = 610, nationally representative) and a conceptual replication with political groups (N = 606, 50% Democrat and 50% Republican). Although the results did not replicate the original findings, we observed evidence of in-group favoritism in minimal groups and out-group derogation in political groups. The current research finds mixed evidence of intergroup moral hypocrisy and has implications for understanding the contextual dependencies of intergroup bias and partisanship

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions’ effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior—several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people’s initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors.

Although much of human morality evolved in an environment of small group living, almost six billion people use the internet in the modern era. We argue that the technological transformation has created an entirely new ecosystem that is often mismatched with our evolved adaptations for social living. We discuss how evolved responses to moral transgressions, such as compassion for victims of transgressions and punishment of transgressors, are disrupted by two main features of the online context. First, the scale of the internet exposes us to an unnaturally large quantity of extreme moral content, causing compassion fatigue and increasing public shaming. Second, the physical and psychological distance between moral actors online can lead to ineffective collective action and virtue signaling. We discuss practical implications of these mismatches and suggest directions for future research on morality in the internet era.