The presence of temporal pauses during list presentation can markedly improve immediate memory for a sequence of verbal items. A series of experiments analysed this effect using Baddeley's (1986) model of working memory. Experiment 1 showed that the effect of temporal grouping on memory for visual sequences was removed by either articulatory suppression or reciting random digits. Experiment 2 indicated that effects of temporal grouping were insensitive to the word length of the items. Experiment 3 showed that articulatory suppression did not remove the temporal grouping effect for auditory lists. Experiment 4 showed that the temporal grouping effect was insensitive to the phonemic similarity of the items. The effects of concurrent articulation suggest that grouping influences the phonological loop component of working memory. However, the working memory model is insufficiently well specified to account for the insensitivity of grouping effects to word length and phonemic similarity. The main findings could be simulated by a connectionist model of the phonological loop, which invokes a context timing signal (Burgess & Hitch, 1992, in press), This assumed that pauses during list presentation affect the timing signal in a similar way to the pause before list presentation and made some novel predictions.