Comparison of pure-tone with two-tone discrimination

Previous work from this laboratory has suggested that the discriminability of complementary two-tone complexes is based upon differences in envelope-weighted averages of instantaneous frequency. It seems plausible that pure-tone frequency discrimination and two-tone discrimination may be mediated by a common underlying process. The study was designed to investigate this possibility by comparing the discriminability of complementary two-tone complexes with pure-tone frequency discrimination as signal duration or signal level were varied. Preliminary results indicate either that a common discrimination mechanism is unlikely, or that the envelope-weighted average of instantaneous frequency model should be modified. [Work supported by NIH.]