During vocabulary instruction, it is important to teach words until their representations are robust enough to be retained. For adults, the number of training sessions a target item is successfully retrieved during training predicts the likelihood of post-training retention. To assess this relationship in children, we reanalyzed data from Gordon et al. (2021b, 2022). Four- to six-year-old children completed six training days with word form-object pairs and were tested one month later. Results indicate that the number of training sessions that a word form was retrieved was positively related to post-training retention. We discuss implications for vocabulary instruction and interventions.

Research has produced mixed findings regarding the effects of spacing L2 study. In order to know how this potentially very powerful learning tool can be useful, it is important to understand the cognitive mechanisms that drive the effects in L2 learning and how the operation of these mechanisms may be affected by variables relevant for SLA contexts. In this study, I examine the contribution of the dual mechanism of successful effortful retrieval during study to the lag effect in foreign vocabulary learning from L2-L1 retrieval practice. I additionally investigate the effects of feedback study time on the operation of the two cognitive mechanisms under investigation. Native speakers of English studied Finnish vocabulary during L2-L1 retrieval practice in paired-associate learning while their response latencies and accuracy were recorded. Results suggest that: (a) successful effortful retrieval underlies benefits of spacing L2-L1 retrieval practice: even with immediate feedback study, the benefits of effort are conditional on retrieval success; (b) successful retrieval is more beneficial than unsuccessful retrieval, contrary to proposals where this was not directly tested; and (c) imposing longer study time externally has little benefit, unlike what has been previously found with learner-regulated longer study time. Implications for L2 learning and teaching are discussed.

Retrieving information by testing improves subsequent retention more than restudy, a phenomenon known as the retrieval practice effect. According to the retrieval effort hypothesis (REH), difficult items require more retrieval effort than easier items and, consequently, should benefit more from retrieval practice. In two experiments, we tested this prediction. Participants learned sets of easy and difficult Swahili–Portuguese word pairs (study phase) and repeatedly restudied half of these items and repeatedly retrieval practiced the other half (practice phase). Forty-eight hours later, they took a cued-recall test (final test phase). In both experiments, we replicated both the retrieval practice and the item difficulty effects. In Experiment 1 (N = 51), we found a greater retrieval practice effect for easy items, MDifference = .26, SD = .17, than for difficult items, MDifference = .19, SD = .19, t(50) = 2.01, p = .05, d = 0.28. In Experiment 2 (N = 28), we found a nonsignificant trend—F(1, 27) = 2.86, p = .10, $$ {\upeta}_{\mathrm{p}}^2 $$ = .10—toward a greater retrieval practice effect for difficult items, MDifference = .28, SD = .22, than for easy items, MDifference = .18, SD = .21. This was especially true for individuals who benefit from retrieval practice (difficult: MDifference = .32, SD = .18; easy: MDifference = .20, SD = .20), t(24) = –2.08, p = .05, d = –0.42. The results provide no clear evidence for the REH and are discussed in relation to current accounts of the retrieval practice effect.