Changing behaviours might be central to responding to societal issues such as climate change and pandemics. In this Review, Albarracín et al. synthesize meta-analyses of individual and social-structural determinants of behaviour and the efficacy of behavioural change interventions that target them across domains to identify general principles that can inform future intervention decisions.

Declines in adolescent mental health over the past decade have been attributed to social media, but the empirical evidence is mixed. In this Review, Orben et al. describe the mechanisms by which social media could amplify the developmental changes that increase adolescents’ mental health vulnerability.

Large language models (LLMs), which can generate and score text in human-like ways, have the potential to advance psychological measurement, experimentation and practice. In this Perspective, Demszky and colleagues describe how LLMs work, concerns about using them for psychological purposes, and how these concerns might be addressed.

An artificial boundary is often drawn between research and activism, but scholar activism can be good for science and for society when it centres the needs of people who are multiply marginalized — especially during the current climate crisis.

The EU commission’s Digital Services Act aims to protect children and adolescents from psychological harm on social media platforms. This initiative needs to be carried out in close cooperation between the EU commission and independent academics.