When young adults detected auditory stimuli at split-second intervals, different components of the event-related brain potentials showed markedly different speeds of recovery. The P3 component (latency 300 to 350 milliseconds) was fully recovered at intervals of less than 1.0 second, while the N1--P2 components (latencies 100 to 180 milliseconds) were markedly attenuated with stimulus repetition even at longer interstimulus intervals. Thus, the N1--P2 recovers much more slowly than a subject's ability to evaluate signals, whereas the P3 appears to be generated at the same high rates as the decision processes with which it is associated.