Revisiting “Stress Deafness” in European Portuguese – An ERP Study

Several behavioral studies have suggested that speakers of languages with variable stress (e.g., Spanish) are better than speakers of languages with fixed stress (e.g., French) at discriminating stress contrasts. European Portuguese (EP) is a language with variable stress, and the main cues for stress are duration and vowel reduction. However, when the vowel quality cue is absent, native speakers are not able to behaviorally discriminate nonsense words that differ only in stress pattern. Using a passive oddball paradigm, the present study recorded event-related potentials (ERPs) to investigate whether native speakers of EP can unintentionally discriminate CVCV pseudo-words with trochaic and iambic stress patterns in the absence of vowel reduction. The results showed that both the trochaic and iambic conditions yielded mismatch negativity (MMN) and late negativity. Moreover, the components in the iambic condition span over a larger temporal window than in the trochaic condition. These results suggest that native speakers of EP can discriminate stress patterns without vowel quality cues at the unintentional level. Furthermore, they are more sensitive to the iambic stress pattern than the trochaic one, which is at odds with their relative frequency in the language, but matches recent developmental findings in the acquisition of stress.