Working memory (WM) maintains task-relevant information and is closely linked with action
planning. We examined how this relationship affects WM updating using a delayed-match-tosample
task in a preregistered study (OSF). Participants memorized a target-colored shape and,
after a retention, identified its color on a color wheel. The shape of the target color indicated
which hand they should use to adjust the color wheel. During retention, participants completed
a secondary task requiring a response with either the right or left hand, which either matched
or mismatched the target hand from the main task. This secondary task introduced either motor
interference or visuomotor interference, the latter involving a randomly colored task cue. We
hypothesized that (I) action plans would form simultaneously during WM encoding, (II)
visuomotor interference would disrupt target representation more than motor interference, and
(III) the interference involving the same hand as the main task would trigger WM updating.
First, EEG analysis revealed mu/beta suppression during WM encoding, suggesting
simultaneous preparation of action plans. Second, visuomotor interference impaired target
representation more than motor interference, as evident in main task errors. Finally, when the
interfering action involved the same hand as the main task, it triggered WM updating, reflected
by a stronger attraction bias of the target color toward the interfering color. This correspondence
also resulted in differences in frontal theta activity, which is associated with WM gating
processes. These findings suggest that shared motor components between planned actions and
interference lead to further processing of sensory information through WM updating.