Accessory tone stimuli facilitate response performance despite being completely irrelevant for the current task. In order to investigate which processes are affected by accessory stimuli, we presented accessory tones in a simple RT task while varying the contingencies between accessory stimulation and either responses (Experiment 1) or stimulus conditions (Experiment 2). Accessory tones speeded up responding to a larger degree when they were conjointly presented within Go compared to No-go trials. In contrast, contingency variation with stimulus conditions did not alter the impact of accessory stimuli. Additionally, accessory tones increased response force. Thus, we conclude that accessory tones influence response-related and not perceptual processes.