Human observers performed two simultaneous increment detection tasks, one in each ear. This task, together with monaural and binaural control conditions, was used to investigate interaural time sharing, sensory inter‐actions, internal noise, and binaural decision spaces. When the signals were binaurally in phase, there was no evidence of cross‐channel facilitation or inhibition, and the observers were able to perform the task without performance decrements relative to single‐channel control conditions. For one observer, the derived estimate of the between‐channel correlation in the absence of an external masking noise was +0.40 and was consistent across different experimental conditions. Differences in the results for 180° phase‐shifted signals indicated probable changes in the nature of the processing mechanisms involved in the detection of the different types of signals. The paradigm and related analyses should be of value in the study of other kinds of perceptual phenomena.