Learning a Phonological Contrast Modulates the Auditory Grouping of Rhythm

Perceptual grouping is fundamental to many auditory processes. The Iambic-Trochaic Law (ITL) is a default grouping strategy, where rhythmic alternations of duration are perceived iambically (weak-strong), while alternations of intensity are perceived trochaically (strong-weak). Some argue that the ITL is experience dependent. For instance, French speakers follow the ITL, but not as consistently as German speakers. We hypothesized that learning about prosodic patterns, like word stress, modulates this rhythmic grouping. We tested this idea by training French adults on a German-like stress contrast. Individuals who showed better phonological learning had more ITL-like grouping, particularly over duration cues. In a non-phonological condition, French adults were trained using identical stimuli, but they learned to attend to acoustic variation that was not linguistic. Here, no learning effects were observed. Results thus suggest that phonological learning can modulate low-level auditory grouping phenomena, but it is constrained by the ability of individuals to learn from short-term training.