Minimal training duration inducing near transfer in two-phase working memory training paradigm

Working memory (WM) training typically induces large improvements on trained tasks, while evidence for whether these improvements transfer to other tasks remains mixed. Using a novel two-phase WM training paradigm, the present study investigated the role of training duration and the underlying mechanisms of training from the perspective of cognitive skill learning. In two experiments, we examined whether the cross-phase near transfer effects observed by Ni et al. (2023) could still be observed with minimal training durations. Both experiments involved two sets of adaptive training on serial order backward recall tasks with verbal or spatial stimulus domains. In Experiment 1, participants completed a single session of 100 trials in both training phases, but no evidence of transfer was observed. In Experiment 2, we extended the first training phase to three sessions with a total of 240 trials, and observed that backward digit span training positively transferred to subsequent backward letter span training. In contrast, backward circle span training did not enhance subsequent backward letter span training and instead showed a trend toward negative transfer. These findings suggest that transfer effects are unstable with these minimal training durations. Therefore, we recommend at least three to five training sessions per phase, as implemented by Ni et al. (2023), to ensure reliable acquisition and transfer of cognitive skills. Overall, this study highlights the potential of the two-phase training paradigm and provides practical guidance for developing more effective training protocols in future research.