Optimizing distributed practice online: A conceptual replication of Cepeda et al. (2009)

This study conceptually replicates Cepeda, Coburn, Rohrer, Wixted, Mozer, & Pashler’s (2009, Experiment 1) study on the effects of distributed practice on second language (L2) vocabulary learning to examine its generalizability to a new context and population sample. The secondary focus of the paper is to examine the challenges and affordances of online data collection and participant recruitment sites. Both the original and our study examined the effects of distributed practice on two study sessions to learn L2 vocabulary assessed on a 10-day delayed posttest. Our results showed that the spaced conditions significantly outperformed the massed condition, mirroring the original study’s findings. However, Cepeda et al.’s (2009) participants outscored our participants by 10–20% (in each experimental group) on the posttest. While these findings highlight the benefits of spacing towards learning and memory, they also underscore the challenges researchers may face when conducting experimental research in online environments. Copyright © 2025 The Author(s).