Individual differences in auditory scene analysis abilities in music and speech.

Auditory scene analysis (ASA) is the ability to organize complex auditory mixtures into meaningful events and streams and is fundamental for auditory perception of both music and speech. Individual differences in ASA are recognized in the literature, yet the factors driving this variability remain poorly understood. This study employs a novel music-based ASA task, the Musical Scene Analysis (MSA) test, alongside a speech-in-noise test, to examine the influence of hearing loss, age, working memory capacity (WMC), and musical training. Ninety-two participants were categorised into four groups: 31 older normal-hearing, 34 older hearing-impaired, 26 younger normal-hearing, and one younger hearing-impaired individual. Results reveal a moderate correlation between ASA performance in speech and music (r = - .5), suggesting shared underlying perceptual processes, yet the factors influencing individual differences varied across domains. A dual modelling approach using ridge regression and gradient-boosted decision trees identified hearing loss as the strongest predictor of speech-based ASA, with a weaker effect of age, while musical training and WMC had no impact. In contrast, musical training showed a substantial effect on musical ASA, alongside moderate effects of hearing loss and age, while WMC exhibited only a marginal, non-robust effect. These findings highlight both shared and domain-specific factors influencing ASA abilities in music and speech.