Working memory (WM) training has been shown to increase the performance of participants in WM tasks and in other cognitive abilities, but there has been no study comparing directly the impact of training format (individual vs. group) using the same protocol. Therefore, the aim of this study was to compare the efficacy of the Borella et al. three session verbal WM training offered in two different formats on target and transfer tasks. This study was conducted in two waves. In the first wave, participants were randomized into individual training (n = 11) and individual control conditions (n = 15). In the second wave, participants were randomized into group training (n = 16) and group control conditions (n = 17). Training consisted of three sessions of WM exercises and participants in the active control condition responded to questionnaires during the same time. There was significant improvement for both training conditions at post-test and maintenance at follow-up for the target task, other WM tasks, processing speed, and executive functions tasks. The ANOVA results showed that the training gains did not depend on the WM training format. However, the effect size analyses suggested that this intervention can be more effective, at short term and follow-up, when provided individually. To conclude, this study showed that providing this training collectively or individually does not change the training benefits, which increases the possibilities of its use in different contexts.
Keywords: Format of training; Older adults; Working memory training.