We report the first set of results in a multi-year project to assess the robustness – and the factors promoting robustness – of the adult statistical word segmentation literature. This includes eight total experiments replicating six different experiments. The purpose of these replications is to assess the reproducibility of reported experiments, examine the replicability of their results, and provide more accurate effect size estimates. Reproducibility was mixed, with several papers either lacking crucial details or containing errors in the description of method, making it difficult to ascertain what was done. Replicability was also mixed: although in every instance we confirmed above-chance statistical word segmentation, many theoretically important moderations of that learning failed to replicate. Moreover, learning success was generally much lower than in the original studies. In the General Discussion, we consider whether these differences are due to differences in subject populations, low power in the original studies, or some combination of these and other factors. We also consider whether these findings are likely to generalize to the broader statistical word segmentation literature.

We replicated Exp. 1 of Saffran, Johnson, Newport, & Aslin (1999) Statistical learning of tone sequences by human infants and adults, as part of a multi-year effort to replicate every adult statistical word segmentation study. While we were able to replicate the finding of above- chance statistical segmentation of tone sequences, many of the other findings reported in the original paper did not replicate.

We replicated Exp. 1 of Saffran, Newport, & Aslin (1996) Word segmentation: The role of distributional Cues, Journal of Memory and Language, 35, 606-621, as part of a multi-year project to replicate every published adult statistical word segmentation study. Despite a much larger sample than the original (101 subjects vs. 24), evidence of successful segmentation was weak and mixed, and none of the item or condition effects replicated. We consider whether this is more likely to be a failure of replication or a failure of generalization (e.g., to a different population).

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