Temporal sequence discrimination of dichotic tones: the effect of frequency.

The present study was designed to investigate the effect of stimulus frequency on the ability to discriminate the temporal sequence of two 250 ms-duration dichotic stimuli. Dichotic stimulus pairs of three frequencies were tested, 493 Hz, 988 Hz and 3982 Hz, using a three-alternative forced-choice design. The results indicate that frequency does not affect the form, the slope or the location along the abscissa of the discrimination functions. All functions reached 67% discrimination level with a dichotic temporal asymmetry of approximately 40-45 ms.