Tuning curve widths of infants and adults in simultaneous and nonsimultaneous masking

Abstract

Tuning curve widths were estimated using the pulsation threshold (PT) technique for infants, 6‐month‐olds, and adults. The observer‐based psychoacoustic procedure [L. W. Olsho et al., Dev. Psychol., in press (1987)] was the test procedure. Listeners discriminated a train of alternating masker and probe tone bursts from a train of masker tone bursts presented with a continuous probe tone. These stimuli were presented in a background of broadband noise at 20‐dB pressure spectrum level. The probe level was 10 dB SL. PTs were obtained at the tuning curve tip and at two points, one above and one below the probe frequency, 10 dB above the tip. The resulting Q10s were compared to those obtained in simultaneous masking for 6‐month‐olds and adults [L. W. Olsho, Inf. Behav. Dev. 8, 371–384 (1985)]. Adult Q10s were significantly greater for PT tuning curves at 500, 1000, and 4000 Hz. Infant PT Q10s were significantly greater than simultaneous masking Q10s at 500 and 1000 Hz, but not at 4000 Hz. [Work supported by NIH.]