Intensity Discrimination of Noise in the Presence of Band-Reject Noise

Abstract

Weber's law holds over at least an 80-dB range for intensity discrimination of 200-msec noise bursts. Weber's law also holds over at least an 80-dB range when information regarding intensitive differences is effectively restricted by the addition of a band-reject noise to a range of frequencies for which pure-tone absolute thresholds are relatively constant. In particular, no saturation effects at high intensities were observed. These results indicate that spread-of-excitation across frequency is not necessary for the auditory system to maintain a large dynamic range. These data, together with recent indications of limited variability of absolute thresholds for VIIIth nerve units of a given characteristic frequency, further suggest that the system can maintain this large dynamic range even when no “fresh” fibers are available for recruitment.