Research on infant cognitive development is often statistically insufficiently powerful and replicability is a serious problem. A consortium of four baby labs will replicate two fundamental studies, which play a key role in debates on the learning mechanisms involved in language acquisition (Marcus et al. 1999) and on the cognitive benefits of bilingualism (Kovács and Mehler, 2004). By replicating each study in all four laboratories, we can improve the statistical power of the studies and test the robustness of the original results from these two important infant studies.