How do articulatory rehearsal and attentional refreshing interact with phonological similarity in the complex span paradigm?

Within Time-Based Resource-Sharing model (Barrouillet et al., 2004), working memory capacity depends on the amount of attention available to maintain information. The aim of this study was to investigate the interplay of attentional refreshing and articulatory rehearsal (Baddeley, 1986). The phonological similarity effect was investigated in a complex span paradigm using lists of similar or dissimilar words to remember. In Experiment 1, the amount of attention available was manipulated by the attentional demand of the concurrent processing task (Simple Reaction Task vs Choice Reaction Task), and in Experiment 2 by varying the pace of stimulus presentation in the CRT. Moreover, in Experiment 1, the hypothesis of that interference arises from feature overwriting (Oberauer & Kliegl, 2006) was tested using two levels of features overlapping for dissimilar words. In both experiments, results revealed an effect of concurrent processing task and of pace on word recall, but no similarity effect. However, similarity effect appeared in simple span paradigm using the same memory materials. Two independent mechanisms seem to be implied in maintenance of information in working memory: articulatory loop involved when time is limited (simple span) and higher cognitive mechanism (attention) involved when concurrent attention demanding processes are carried out.