Addressing climate change with behavioral science: A global intervention tournament in 63 countries.

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.

Testing a first online intervention to reduce conformity to cyber aggression in messaging apps.

Early adolescents frequently use mobile messaging apps to communicate with peers. The popularity of such messaging apps has a critical drawback because it increases conformity to cyber aggression. Cyber aggression includes aggressive peer behaviors such as nasty comments, nonconsensual image sharing, and social exclusion, to which adolescents subsequently conform. Recent empirical research points to peer group norms and reduced accountability as two essential determinants of conformity to cyber aggression. Therefore, the current study aimed to counteract these two determinants in a 2 (peer group norms counteracted: yes, no) x 2 (reduced accountability counteracted: yes, no) design. We created four intervention conditions that addressed adolescents' deficits in information, motivation, and behavioral skills. Depending on the condition (peer group norms, reduced accountability, combination, or control), we first informed participants about the influence of the relevant determinant (e.g., peer group norms). Subsequently, participants performed a self-persuasion task and formulated implementation-intentions to increase their motivation and behavioral skills not to conform to cyber aggression. Effectiveness was tested with a messaging app paradigm and self-report among a sample of 377 adolescents (Mage = 12.99, SDage = 0.84; 53.6% boys). Factorial ANCOVAs revealed that none of the intervention conditions reduced conformity to cyber aggression. Moreover, individual differences in susceptibility to peer pressure or inhibitory control among adolescents did not moderate the expected relations. Therefore, there is no evidence that our intervention effectively reduces conformity to cyber aggression. The findings from this first intervention effort point to the complex relationship between theory and practice. Our findings warrant future research to develop potential intervention tools that could effectively reduce conformity to cyber aggression.