Small procedural differences matter: Conceptual and direct replication attempts of the communication-intervention effect on infants’ false-belief ascriptions

The current replication crisis in experimental psychology has also called into question findings regarding infants’ early false-belief understanding. It is, however, debated whether non-replications might be due procedural differences between replication attempts and original studies. The current set of studies aimed to shed light on this question by trying to replicate a violation-of-expectation study by Song, Onishi, Baillargeon and Fisher (2008). This task seemed especially important since it addressed not only the question whether or not infants hold false-belief assumptions but whether they update them given informative verbal input. Studies 1a and 1b failed to replicate the original findings conceptually. Study 2 – which followed the original procedure more closely – replicated the original finding regarding informative interventions. However, the same effect was found with so-called uninformative statements. We argue that theoretically, children should update their expectations when communication takes place and that other, more subtle features of a task might influence infants’ performance. Overall, the current set of studies emphasizes that direct replication attempts for single studies need to follow the original design and procedure as closely as possible.