Frequency Discrimination and Detection of Homophasic and Antiphasic Tonal Signals in Noise

Abstract

Psychometric functions generated in a 2ATFC detection paradigm were compared to psychometric functions generated in a 2ATFC frequency-discrimination paradigm (see Henning, J. Acoust. Soc. Amer. 41, 4 (1967)]. For frequency discrimination, two tones were presented, one in each of the two observation intervals. The observer's task was to indicate in which interval the signal of higher frequency occurred. With a frequency difference of 15 Hz, the psychometric function for frequency discrimination of homophasic signals was parallel to and slightly displaced to the right of the psychometric function for detection of homophasic signals. The psychometric function for frequency discrimination of antiphasic signals, however, had a significantly lower slope than the psychometric function for detection of antiphasic signals. Performance for frequency discrimination of antiphasic signals was similar to performance for detection of antiphasic signals at low S/N ratios and similar to detection of homophasic signals at high S/N ratios. The data are discussed in view of current models of binaural signal processing.