Advancing the psychology of social class with large-scale replications in four countries

Theoretical models have been developed to understand how social class influences individual thoughts, feelings and behaviours. However, the validity of these models is threatened by the prevailing use of small, non-diverse samples and flexible measurement practices. We preregistered replications of 35 key hypotheses from 17 correlational and 5 experimental studies, and collected large, quota-based or probability samples from the USA, France, Switzerland and India (N_total = 33,536). Our analysis yielded three central findings: (1) ~50% of the effects were successfully replicated; (2) conclusions were consistent across different operationalizations of social class, although objective indicators yielded smaller estimates (for example, income and education); and (3) half of the effects were moderated—mostly strengthened—by social class identification, system-justification beliefs or local income inequality. Overall, hypotheses based on differences between social class contexts in terms of constraints, uncertainty and status were well supported. However, hypotheses based on models positing social class differences in psychological orientations towards ‘the self’ versus ‘others and the environment’ received less support. We conclude that these models need to be reassessed as individuals from higher social classes seem more oriented towards both themselves and others. The Stage 1 protocol for this Registered Report was accepted in principle on 29 October 2021. The protocol, as accepted by the journal, can be found at https://doi.org/10.17605/OSF.IO/B6Y8R.