Certain properties of a feature detector system sensitive to VOT were investigated with a binaural adaptation‐dichotic testing paradigm. On each dichotic test trial, a nonboundary voiced stop was paired with one of a set of voiceless stops. The voiceless stops varied in VOT, from values close to the phonetic boundary to values well within the voiceless category. The relative effectiveness of each of the voiceless stimuli in competing for processing with the voiced stimulus was assessed before adaptation and after adaptation with voiceless stops with a range of VOT values. During both pre‐ and postadaptation, the number of correct voicing responses when targeting for the voiceless stop, and the number of voicing intrusions when targeting for the voiced stop, systematically varied as a function of the VOT value of the voiceless stimulus. In addition, the VOT value of the adapting stimulus determined the amount of adaptation obtained. These results indicate first, that the output of the detector is a graded signal, and second, that the magnitude of decrease in detector sensitivity during adaptation is a function of the VOT value of the adapting stimulus. [Supported by NIH grants.]