Non-Auditory Participant Characteristics Influence Digit-Perception Performance: Evidence From Tasks Varying in Masker Type and Spatial Cues.

Digit-perception tasks are widely used to assess auditory function in clinical and research settings, but performance may also be shaped by non-auditory participant characteristics. This study examined whether educational attainment, forward digit span, socioeconomic deprivation, and musical experience predicted performance on three digit-perception tasks that differed in masker type and spatial demands: digits in speech-shaped noise (SSN), digits in spatially separated babble, and a spatial-selective-attention task in which digit streams were separated by 15°. Participants were 220 young adults (aged 16-17 years at baseline) with bilaterally normal audiometric thresholds, each tested twice. The narrow age range and normal hearing constrained variation in peripheral auditory function, increasing sensitivity to non-auditory influences. Linear mixed-effects models were used to examine single-predictor and multivariate associations between the predictors and each outcome. Digits-in-SSN performance was unrelated to all predictors. Digits-in-babble thresholds showed modest associations with deprivation and educational attainment in single-predictor models, but neither survived multivariate adjustment. By contrast, spatial-selective-attention performance showed robust independent associations with educational attainment, deprivation, and musical experience after mutual adjustment. Forward digit span was not a significant predictor of any task. These findings indicate that spatially demanding digit-perception tasks are vulnerable to non-auditory confounds, and that controlling for short-term memory may be insufficient to address this problem. A secondary analysis examined whether the association between musical experience and spatial selective attention might reflect confounding rather than auditory training. The musician advantage was attenuated by approximately one third after adjustment for sociodemographic factors, consistent with a substantial contribution of confounding.