The psychoacoustical literature contains multiple reports about small differences in performance depending upon the sex and phase of the menstrual cycle of the subjects. In an attempt to verify these past reports, a large-scale study was implemented. After extensive training, the performance of about 75 listeners was measured on seven common psychoacoustical tasks. For most tasks, the signal was a 3.0-kHz tone. The initial data analyses failed to confirm some past outcomes. Additional analyses, incorporating the limited information available about the racial background of the listeners, did confirm some of the past reports, with the direction and magnitude of the differences often diverging for the White and Non-White listeners. Sex differences and race differences interacted for six of the seven tasks studied. These interactions suggest that racial background needs to be considered when making generalizations about human auditory performance, and when considering failures of reproducibility across studies. Menstrual differences were small, but generally larger for Whites than Non-Whites. Hormonal effects may be responsible for the sex and cycle differences that do exist, and differences in intra-cochlear melanocytes may account for the race differences.

Performance was measured on seven common psychoacoustical tasks for about 75 highly trained subjects. Because some psychoacoustical outcomes varied by race, the subjects were partitioned into White and Non-White categories for analysis. Sex, race, and menstrual-cycle differences in performance are described in a companion paper [McFadden, Pasanen, Maloney, Leshikar, and Pho (2018). J. Acoust. Soc. Am. 143, 2338-2354]. Also measured for all subjects were three types of otoacoustic emissions (OAEs): spontaneous otoacoustic emissions (SOAEs), click-evoked otoacoustic emissions (CEOAEs), and distortion-product otoacoustic emissions (DPOAEs). The experimental question was whether and how OAEs were correlated with psychoacoustical performance. In accord with past findings, the SOAEs and CEOAEs exhibited substantial sex and race differences, but the DPOAEs did not. Somewhat surprisingly, the correlations between OAEs and psychoacoustical performance were generally weak. No form of OAE was highly correlated with any psychoacoustical task for both sexes within a race category. Thus, there was no compelling evidence that the mechanisms underlying OAEs also contribute systematically to performance in any of the simultaneous or temporal masking tasks studied here. Especially surprising were the weak correlations between OAEs and detection of a tone in the quiet. Apparently individual differences in psychoacoustical performance reside more in post-cochlear (neural) mechanisms than in individual differences in the cochlear ("mechanical") mechanisms underlying the OAEs measured here.

Both distortion-product otoacoustic emissions (DPOAEs) and performance in an auditory-masking task involving combination tones were measured in the same frequency region in the same ears. In the behavioral task, a signal of 3.6 kHz (duration 300 ms, rise/fall time 20 ms) was masked by a 3.0-kHz tone (62 dB SPL, continuously presented). These two frequencies can produce a combination tone at 2.4 kHz. When a narrowband noise (2.0-2.8 kHz, 17 dB spectrum level) was added as a second masker, detection of the 3.6-kHz signal worsened by 6-9 dB (the Greenwood effect), revealing that listeners had been using the combination tone at 2.4 kHz as a cue for detection at 3.6 kHz. Several outcomes differed markedly by sex and racial background. The Greenwood effect was substantially larger in females than in males, but only for the White group. When the magnitude of the Greenwood effect was compared with the magnitude of the DPOAE measured in the 2.4 kHz region, the correlations typically were modest, but were high for Non-White males. For many subjects, then, most of the DPOAE measured in the ear canal apparently is not related to the combination-tone cue that is masked by the narrowband noise.

Auditory brainstem responses (ABRs) and auditory middle-latency responses (AMLRs) to a click stimulus were measured in about 100 subjects. Of interest were the sex differences in those auditory evoked potentials (AEPs), the correlations between the various AEP measures, and the correlations between the AEP measures and measures of otoacoustic emissions (OAEs) and behavioral performance also measured on the same subjects. Also of interest was how the menstrual cycle affected the various AEP measures. Most ABR measures and several AMLR measures exhibited sex differences, and many of the former were substantial. The sex differences tended to be larger for latency than for amplitude of the waves, and they tended to be larger for a weak click stimulus than for a strong click. The largest sex difference was for Wave-V latency (effect size ~1.2). When subjects were dichotomized into Non-Whites and Whites, the race differences in AEPs were small within sex. However, sex and race interacted so that the sex differences often were larger for the White subjects than for the Non-White subjects, particularly for the latency measures. Contrary to the literature, no AEP measures differed markedly across the menstrual cycle. Correlations between various AEP measures, and between AEP and OAE measures, were small and showed no consistent patterns across sex or race categories. Performance on seven common psychoacoustical tasks was only weakly correlated with individual AEP measures (just as was true for the OAEs also measured on these subjects). AMLR Wave Pa unexpectedly did not show the decrease in latency and increase in amplitude typically observed for AEPs when click level was varied from 40 to 70 dB nHL (normal Hearing Level). For the majority of the measures, the variability of the distribution of scores was greater for the males than for the females.

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