Frequency selectivity and masking: Perception

This article explains the processes that determine whether one sound will obscure or mask another sound, with particular regard to the frequency selective mechanisms of the cochlea. Frequency selectivity is the ability to 'hear out' sounds of different frequencies within a complex mixture. It involves the most important organizational principle within the auditory system. Despite being one of the first areas of psychoacoustic investigation, there is currently considerable excitement in the field, as new behavioural techniques have allowed accurate measures of the complex non-linear response properties of the basilar membrane. Masking has been the primary tool with which the limits of frequency selectivity have been probed behaviourally. Methods for estimating frequency selectivity have been refined over the years, and the understanding of the mechanisms of masking, and the limitations of the various masking techniques, has progressed.