Investigating the maintenance of order information in manual-gestural serial recall: Effect of articulatory suppression and irrelevant sound

Abstract

A prominent view within the serial short-term memory literature is the notion of a functional equivalence for the maintenance of order information across the domains of immediate memory. Despite extensive research examining this for verbal, spatial, and, to some extent, visual material, there is a distinct lack of research into the maintenance of item order for manual gestures. As such, the current study aimed to rectify this by examining serial recall performance for manual gestures under varying conditions. Sequences were presented in silence, or in the presence of steady- or changing-state irrelevant sound. Furthermore, in one block of each experiment, articulatory suppression was employed. Serial position effects and relative recency were also examined for the secondary aim of investigating similarities in the encoding and processing of manual gestures. Experiment 1 made use of meaningless manual gestures, with results showing the presence of the changing-state effect which was subsequently eliminated by articulatory suppression. Articulatory suppression also significantly disrupted serial recall performance in all sound conditions. In Experiment 2, non-iconic gestures were used to reduce the potential for verbal recoding. In contrast to Experiment 1, the changing-state effect did not present, and while there was a main effect of articulatory suppression, corrected post-hoc tests revealed non-significant differences. While these results may suggest that participants relied on verbal recoding and subvocal rehearsal in Experiment 1, resulting in similarities to verbal serial recall, the mere ability of irrelevant sound and articulatory suppression to disrupt serial recall performance for manual gestures goes against the working memory model and points towards an amodal mechanism for the maintenance of serial order. As such, it is argued that the perceptual-gestural account is currently better suited to account for the observed effects.