Randomly assigned 300 university students to 10 treatment groups of 30 each. Motor proactive interference, produced by requiring Ss to recall 5 linear lever displacements in reverse order after a 90-sec retention interval, was completely eliminated by an instruction to forget the 1st 4 positions given prior to the presentation of the criterion (5th) response. Proactive interference was significantly reduced by a similar instruction given immediately before recall. Ss' ability to intentionally forget prior motor responses is assumed to explain the inconsistent findings of short-term motor memory research. To-be-forgotten prior items were not completely "discarded," however, since they were recalled as well as to-be-remembered prior items. The discussion centers on the cognitive control of motor behavior and, in particular, on the mechanisms of set differentiation, selective rehearsal, and selective search. (18 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved)