Exploiting individual differences to assess the role of place and phase locking cues in frequency discrimination

Abstract

Abstract The relative role of place and temporal mechanisms in auditory frequency discrimination was assessed for a centre frequency of 2 kHz. Four measures of frequency discrimination were obtained for 63 normal-hearing participants: detection of frequency modulation using modulation rates of 2 Hz (FM2) and 20 Hz (FM20); detection of a change in frequency across successive pure tones (difference limen for frequency, DLF); and detection of changes in the temporal fine structure of bandpass filtered complex tones centred at 2 kHz (TFS). Previous work has suggested that: FM2 depends on the use of both temporal and place cues; FM20 depends primarily on the use of place cues because the temporal mechanism cannot track rapid changes in frequency; DLF depends primarily on temporal cues; TFS depends exclusively on temporal cues. This led to the following predicted patterns of the correlations of scores across participants: DLF and TFS should be highly correlated; FM2 should be correlated with DLF and TFS; FM20 should not be correlated with DLF or TFS. The results were broadly consistent with these predictions, supporting the idea that frequency discrimination at 2 kHz depends partly or primarily on temporal cues except for frequency modulation detection at a high rate.