In the present study, we examined whether the use
of partial information for response preparation depends
on the utility of that partial information for meeting
task demands. Using a choice/Nogo task, the utility of
the partial information was varied by manipulating the
proportion of Go relative to Nogo signals, and preliminary
response preparation was indexed by the degree of lateralized
readiness potential (LRP) activity on Nogo trials. The
Nogo LRP was clearly present when Go probability was high
(67% Go) and, to a lesser extent, when Go and Nogo signals
were equiprobable. However, the Nogo LRP disappeared when
the probability of a Go signal was low (25% Go). This pattern
of results supports the hypothesis that response preparation
will be based on partial stimulus information only when
the information has significant utility in the context
of the overall task requirements.