Phonetic categorization and discrimination of voice onset time under divided attention

Event durations are perceived to be shorter under divided attention. “Time shrinkage” is thought to be due to rapid attentional switches between tasks, leading to a loss of input samples, and hence, an under-estimation of duration. However, few studies have considered whether this phenomenon applies to durations relevant to time-based phonetic categorization. In this study, participants categorized auditory stimuli varying in voice onset time (VOT) as /ɡ/ or /k/. They did so under focused attention (auditory task alone) or while performing a low-level visual task at the same time (divided attention). Under divided attention, there was increased response imprecision but no bias toward hearing /ɡ/, the shorter-VOT sound. It is concluded that sample loss under divided attention does not apply to the perception of phonetic contrasts within the VOT range.