Previous findings suggest that motoric response
preparation cannot be initiated in parallel with memory
scanning. In the present study, response preparation was
initiated with the aid of a precue to examine whether such
preparation can be maintained or continued while memory
scanning is active. In Experiment 1, each trial began with
a colored square indicating which hand might be needed
to respond. A probe letter's memory set membership
determined whether the primed response should be made or
withheld. Lateralized readiness potentials were initiated
by the square precue and continued to increase after letter
presentation, suggesting that once response preparation
had been initiated it was continued in parallel with memory
scanning. Experiment 2 suggested that the difficulty of
the concurrent memory search had little effect on the continuation
of response preparation. The results support the view that
motoric response preparation consists of at least two qualitatively
distinct phases—initiation and continuation.