Power-Group Transformations under Glare, Masking, and Recruitment

A masking stimulus, either visual or auditory, raises the exponent of the psychophysical function relating sensation to stimulus. This power transformation applies only to the part of the function that is influenced by the masking stimulus. Since a given masking noise affects only weaker stimuli, the result is a discontinuous loudness function, which resembles the discontinuous brightness function produced by a glare. The loudness functions for low-frequency stimuli resemble those obtained under masking, as do also the recruitment functions in hard-of-hearing ears.