Acoustic reflex and critical bandwidth

Abstract

The threshold of the acoustic reflex was measured with an electroacoustic impedance bridge in six subjects with normal hearing sensitivity. Reflex thresholds were measured as a function of the bandwidth (1, 10, 30, 100, 300, 1155, 2042 Hz) of an acoustic stimulus centered around 1 kHz, and also for broad-band noise (5780-Hz bandwidth). Acoustic-reflex thresholds were relatively constant for bandwidths between 1 and 300 Hz, and became progressively lower as the bandwidth increased (1155, 2042, 5780 Hz). The data support the idea that there is a critical-band mechanism operating for elicitation of the acoustic reflex, and that the critical bandwidth for the acoustic reflex at 1 kHz is substantially wider than that observed in psychophysical studies.