ManyBabies4



Welcome to the ManyBabies4 project - a cross-lab investigation of infants' social evaluations! ManyBabies is a collaborative project for replication and best practices in developmental psychology research. In ManyBabies4 we are examining infants' preferences for prosocial agents (helpers) over anti-social agents (hinderers).

Learn more about the ManyBabies4 project by reading our new Preprint that recently received an In Principle Acceptance to Developmental Science.

Learn more about our spin-off project focusing on individual differences in infants' social evaluations across cultures by reading our pre-registration on OSF.

Infants' Social Evaluations

Evaluating others’ actions as praiseworthy or blameworthy is a fundamental aspect of human nature. Where does this sense of right and wrong come from?

A seminal study published by Hamlin, Wynn, & Bloom, 2007 suggested that the ability to form social evaluations based on third-party interactions may emerges within the first year of life, considerably earlier than previously thought. ManyBabies4 aims to replicate the original Hamlin et al., 2007 findings and identify moderators of the effect.

Further reading:

Hamlin, J. K., Wynn, K., & Bloom, P. (2007). Social evaluation by preverbal infants. Nature.

Margoni, F., & Surian, L. (2018). Infants’ evaluation of prosocial and antisocial agents: A meta-analysis. Developmental Psychology.

Replicability and Variability

The findings reported by Hamlin, Wynn, & Bloom, 2007 sparked a line of research into the development of infants' social evaluations. However, attempts to replicate this method have yielded mixed results.

Developmental research -- particularly with young infants -- comes with a unique set of reproducibility challenges. The ManyBabies project was designed to address these challenges by bringing researchers together to address difficult outstanding theoretical and methodological questions about the nature of early development and how it is studied.

ManyBabies4 aims to to provide a precise estimate of the true effect size of infants’ preference for prosocial over antisocial individuals, and to determine the degree to which infants’ preferences are based on the social features of the helper/hinderer scenarios. Our multi-lab approach will use a consistent methodology across laboratories, allowing us to more directly tease apart sources of variation.

Further Reading:

Frank, M. C., Bergelson, E., Bergmann, C., Cristia, A., Floccia, C., Gervain, J., … Yurovsky, D. (2017). A Collaborative Approach to Infant Research: Promoting Reproducibility, Best Practices, and Theory-Building. Infancy.

Klein, R. A., Ratliff, K. A., Vianello, M., Adams, R. B., Jr., Bahník, Š., Bernstein, M. J., … Nosek, B. A. (2014). Investigating variation in replicability: A “many labs” replication project. Social Psychology


If you are a lab researching infant perception, cognition, or behavior -- we invite you to join us in these efforts.

Project lead, Kiley Hamlin, discusses infants' social evaluations in the Netflix Series Babies (Part 2, Episode 4)

Getting Started

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