The stimulus range effect: evidence for top-down control of sensory intensity in audition.

The influence of intensity range on the perceived magnitude of a stimulus is well documented and usually attributed to response biases. Recent studies, however, have suggested that the range effect might be sensory in origin. To test this notion, we had one set of subjects compare loudness intervals in three conditions: a broad-range condition (15 tones, 23-95 dB SPL), a soft short-range condition (the lowest 10 tones from the broad-range condition), and a loud short-range condition (the highest 10 tones). Nonmetric scaling showed that the broad-range and loud short-range conditions had identical loudness functions. However, the second derivative of the loudness function was larger for the soft short-range condition than for the broad-range condition. This pattern of results is consistent with the notion of a nonlinear amplifier whose gain and degree of nonlinearity are adjusted under top-down control, so as to prevent distortion and increase discriminability.