Abstract
Working memory capacity is highly limited. However, we can strategically use perceptual grouping cues to improve performance; for instance, it is easier to remember targets that form an illusory shape (Kanizsa illusion) compared to ungrouped targets. Previous work has explored mechanisms underlying the grouping benefit, yet it is unclear what explains individual differences in perceptual grouping strategy. That is, while working memory capacity is linked to individual differences in various cognitive abilities, it may also be related to the effective use of grouping strategies. For instance, higher-capacity individuals may adopt a more optimal strategy. Alternatively, lower-capacity individuals could engage in more strategic encoding to compensate for their capacity limits. Here we assessed individuals’ strategic use of grouping cues to boost working memory performance. Participants performed an orientation change detection task in which they memorized items that were either randomly oriented or aligned to form Kanizsa triangles. Importantly, we presented random and Kanizsa trials in intermixed and blocked conditions to examine potential differences in strategy choice and the ability to implement the strategy. We also independently assessed visual working memory capacity with a color change detection task. Results replicated the Kanizsa grouping benefit: there was better memory for Kanizsa triangles versus randomly oriented items. However, there was no evidence that participants were less likely to use the grouping strategy in intermixed conditions, as the grouping benefit did not differ between intermixed and blocked conditions. Further, there was no correlation between working memory capacity and Kanizsa grouping benefit. Thus, we failed to find evidence that working memory capacity predicts the use of perceptual grouping strategy. Future work using EEG may investigate whether strategic differences and working memory capacity influence how Kanizsa illusions are stored in working memory.