Basic Psychophysics of Human Spectral Processing

Abstract

Publisher Summary This chapter explains that frequency selectivity measured behaviorally in masking experiments, is largely determined by the filtering that occurs on the basilar membrane (BM). The tuning of a specific point of the BM is determined by two components: a passive component reflecting the hydromechanical properties of the BM and surrounding fluids and structures, and an active component reflecting the influence of the outer hair cells (OHCs) on BM motion. The passive component appears to be roughly linear and does not vary with the level, while the active component is highly nonlinear. The nonlinearity greatly complicates the analysis and interpretation of masking experiments. The chapter presents a simple model of masking that ignores these complications, and further discusses. the power-spectrum model and the concept of the critical band,. and various masking and excitation patterns. A major difference between simultaneous and nonsimultaneous masking is that the frequency selectivity revealed in nonsimultaneous masking is greater than that revealed in simultaneous masking. A well-studied example of this is the PTC. PTCs determined in forward masking are typically sharper than those obtained in simultaneous masking.