Two dissociable updating processes in working memory.

The authors show that the updating of working memory (WM) representations is carried out by the cooperative act of 2 dissociable reaction time (RT) components: a global updating process that provides stability by shielding WM contents against interference and a local process that provides flexibility. Participants kept track of 1-3 items (digits or Gibson figures). In each trial, the items either were similar to those in the previous trial or were different in any or all of the items. Experiments 1 and 2 established the existence of 2 independent RT components representing the 2 updating processes. Global updating cost was sensitive to total number of items in WM (set size), regardless of the number of items that actually were modified. Local updating cost was sensitive to the number of modified items, regardless of the set size. Experiment 3 showed that participants had to dismantle the representation formed by previous global updating in order to carry out new updating.