Working memory (WM) updating is a controlled process through which relevant information in the environment is selected to enter the gate to WM and substitute its contents. We suggest that there is also an automatic form of updating, which influences performance in many tasks and is primarily manifested in reaction time sequential effects. The goal of the present study was to dissociate WM updating and automatic updating, characterize the nature of these operations and identify the memory system responsible for each. In addition, we investigated the relationship between WM updating and the P3 event-related potential component. In Experiment 1, we compared the sequential processes in 1-back and 2-alternative forced choice tasks. These results indicated differential sources of sequential processes in the 2 tasks. We proposed that automatic updating operates in long-term memory on representations separate from WM representations. In addition, the event-related potential results of Experiment 1 are inconsistent with the idea that P3 is triggered through WM updating. Subsequently, in Experiments 2-3, we decomposed the 1-back task to major subprocesses. To this end, a new paradigm is introduced: the reference-back task. This paradigm facilitated the empirical distinction between automatic updating, comparison processes, gating and WM updating, within the same task. The results replicated the separate effects of WM updating and automatic updating on performance, and they provided behavioral evidence for a gating mechanism that separates WM from long-term memory.