Age and category structure in phonetic category learning

Abstract

When learning new speech sound categories in a second language, listeners must decide which sounds belong to the same category and which belong to different categories. This learning process is contingent on perceptual systems that change across the lifespan, which may, in turn, make certain categories easier to learn depending on which systems are employed by learners. In the present study, learners across a variety of ages categorize speech sounds taken from German that vary in their category structure (i.e., the complexity of the categories being learned within the stimulus space). Participants aged 7 to 70 are recruited and run at community sites such as museums and libraries. The preliminary dataset indicates that the simpler category structure saw strong age effects (with poorer performance on the younger and older ends of the age range and better performance at intermediate ages), while differences across ages were much smaller for the more complex category structure. These findings suggest that learning simpler category structures may rely on age-dependent learning systems, while learning more complex categories may rely on systems that are less age-dependent.