The purpose of the proposed research is twofold. First, a series of large-scale correlational studies is described, the goal of which is to determine quantitatively the relationships among the major psychoacoustic parameters. The series is organized around (a) critical bandwidths, frequency discrimination, and speech, (b) the shape of the critical bandwidth and lateral inhibition, (c) perceptual effects of complex tonal signals, (d) temporal resolution, and (e) temporary threshold shift. In this sequence of studies, the most unique and reliable measures from preceding correlational studies will be carried over to subsequent studies. In addition, a series of laboratory studies is proposed, which are designed to (1) provide the information necessary for development of standardized test procedures to be included in the later stages of the series of correlational studies and (2) to carry out original research related to indirect measures of critical bandwidth and to temporal resolution. The data from the combined correlational laboratory studies should be particularly useful in establishing a reasonable model for assessing the auditory functioning of hearing- impaired listeners (listeners with impaired hearing will be included in the correlational studies). It should be generally useful, however, in any application that calls for the description of the auditory potential of an individual. Finally, in addition to the inherent significance of the proposed laboratory research to the body of literature in audition, the quantitative determination of the relationships among the major auditory experiments should enable theorists to resolve the many issues in audition that are concerned with the relationships among such variables.