The detectability of the odor of butanol

Three experiments were conducted to measure the sensitivity of two Ss to the odor of butanol. In the first two experiments, the method of double random, yes-no staircases was used. A practice effect of over a log₁₀ unit in millimoles decrease in apparent threshold was observed in both Ss. Consistent shifts in the response criterion were induced when Ss were paid to meet an arbitrarily determined physical criterion. In Experiment S, the confidence rating procedure was used. Results at eight different signal intensities are of the form predicted by signal detection theory. d’ is shown to be related to signal strength by a power function with a slope of about .30 which suggests that the olfactory transducer compresses sensory input produced by weak concentrations of butanol.