European Portuguese (EP) intonational contrast between statement and question contours was tested on a Categorical Perception based paradigm. From two natural sentences one produced by a male speaker and another by a female, one multi-step continuum from each sentence was created, from declarative to question contour, through acoustic manipulation (PSOLA) and submitted to 20 EP listeners that performed two tasks: an identification and a discrimination task.
For the identification test, subjects had to categorize each presented stimulus. In addition to response data, reaction times of the identification task were also collected.
For the discrimination test, subjects were presented with an AX discrimination task and had to decide whether the stimuli in each pair were equal or different. Experimental design and procedures were developed with E-Prime.
Identification results confirmed that the contrast is indeed categorical. However, identification reaction times measurements point to continuous rather than categorical perception. The absence of a consistent peak of discrimination in the crossover between categories supports the continuous perception view.