How precise are verbal working memory representations? Evidence from phonological and semantic similarity

In contrast with the visual working memory (WM) domain, the notion of WM precision has been poorly explored in the verbal WM domain. WM precision is defined as the resolution at which items are represented in WM, in addition to the quantity of items that can be maintained. In this study, which included 51 young adults, we assessed the sensitivity to different degrees of phonological (Task 1) and semantic (Task 2) proximity between memory and probe items as a potential index of verbal WM precision. In both tasks, the participants were presented auditory lists of 6 words. After each list, a probe word was presented, and the participants had to decide whether or not it had been in the list. In Task 1, negative probes showed different degrees of phonological proximity with the target memoranda, while in Task 2, negative probes showed different degrees of semantic proximity with the target item. Using Bayesian ANOVA, we observed robust evidence for a gradual influence of phonological proximity on recognition performance. This was also observed, although to a lesser extent, for semantic proximity. This study indicates that phonological and semantic proximity may be promising tools for exploring WM precision in the verbal domain.