Several psychophysical models for masked detection were evaluated using reproducible noises. The data were hit and false-alarm rates from three psychophysical studies of detection of 500-Hz tones in reproducible noise under diotic ͑N 0 S 0 ͒ and dichotic ͑N 0 S ͒ conditions with four stimulus bandwidths ͑50, 100, 115, and 2900 Hz͒. Diotic data were best predicted by an energy-based multiple-detector model that linearly combined stimulus energies at the outputs of several critical-band filters. The tone-plus-noise trials in the dichotic data were best predicted by models that linearly combined either the average values or the standard deviations of interaural time and level differences; however, these models offered no predictions for noise-alone responses. The decision variables of more complicated temporal models, including the models of Dau et al. ͓͑1996a͒. J. Acoust. Soc. Am. 99, 3615-3622͔ and Breebaart et al. ͓͑2001a͒. J. Acoust. Soc. Am. 110, 1074-1088͔, were weakly correlated with subjects' responses. Comparisons of the dependencies of each model on envelope and fine-structure cues to those in the data suggested that dependence upon both envelope and fine structure, as well as an interaction between them, is required to predict the detection results.

A single-interval, yes-no, tone-in-noise detection experiment was conducted to measure the proportion of "tone present" responses to each of 25 reproducible noise-alone and tone-plus-noise waveforms under narrowband (100 Hz), wideband (2900 Hz), monotic, and diotic stimulus conditions. Proportions of "tone present" responses (estimates of the probabilities of hits and false alarms) were correlated across masker bandwidths and across monotic and diotic conditions. Two categories of models were considered; one based on stimulus energy or neural counts, and another based on temporal structure of the stimulus envelope or neural patterns. Both categories gave significant correlation between decision variables and data. A model based on a weighted combination of energy in multiple critical bands performed best, predicting up to 90% of the variance in the reproducible-noise data. However, since energy-based models are unable to successfully explain detection under a roving-level paradigm without substantial modification, it is argued that other variations of detection models must be considered for future study. Temporal models are resistant to changes in threshold under roving-level conditions, but explained at most only 67% of the variance in the reproducible-noise data.

Subject responses were measured for individual narrow-band reproducible stimuli in a low-frequency tone-in-noise detection task. Both N0S0 and N0Spi conditions were examined. The goal of the experiment was to determine the relative importance of envelope and fine-structure cues. Therefore, chimeric stimuli were generated by recombining envelopes and fine structures from different reproducible stimuli. Detection judgments for noise-alone or tone-plus-noise stimuli that had common envelopes but different fine structures or common fine structures but different envelopes were compared. The results showed similar patterns of responses to stimuli that shared envelopes, indicating the importance of envelope cues; however, fine-structure cues were also shown to be important. The relative weight assigned to envelope and fine-structure cues varied across subjects and across interaural conditions. The results also indicated that envelope and fine-structure information are not processed independently. Implications for monaural and binaural models of masking are discussed.

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In order to test monaural and binaural processing components of binaural detection, diotic and monaural detection were studied using reproducible noises. Correlations across masker bandwidth and interaural configuration were computed. Preliminary results reveal high correlations for probability of detection across N0S0 and NmSm configurations for both wideband and narrow-band maskers, suggesting that the binaural system does not influence results across reproducible noises for diotic detection. As reported previously [Evilsizer et al., J. Acoust. Soc. Am. 111, 336–345 (2001)], significant differences in correlations between wideband and narrow-band results were observed for the diotic case, suggesting cross-frequency interactions. Preliminary findings indicate that the same result holds for the monaural case. These data will be used to test models that incorporate monaural processing based on the phase-opponency model [Carney et al., Acta Acustica United with Acustica 88, 334–347 (2002)], and binaural processing based on the Jeffress model and on the two-channel model [McAlpine et al., Nature Neurosci. 4, 396–401 (2001)]. Predictions will be made for NmSm, N0S0, and N0Sπ interaural configurations, and for wideband and narrow-band maskers. [Work supported by NIDCD.]