Haptic‐auditory interference from air flow in speech perception

Previous work on haptic interference in auditory perception has shown McGurk‐like effects from manual‐tactile contact with the face [Fowler and Dekle, JEP:HPP 17, 816–828 (1991)]. The present study investigates whether indirect haptic input affects auditory perception. A novel method was developed in which one experimenter blew puffs of air onto a subject’s neck while another produced English plosives, creating possible mismatches between the sensation of aspiration and its acoustic presence. Subjects were blindfolded and wore headphones playing white noise. For 50% of the trial, one experimenter, whose presence was hidden from the subjects, blew puffs of air on subjects’ necks lightly enough to be perceived but not noticeable as unnatural. Simultaneously, a second experimenter produced syllables with bilabial plosive onsets (aspirated /p/ or unaspirated /b/) and subjects were asked to repeat what was heard. Sessions were videotaped and three observers rated successful simultaneity of stimuli. Results indicate cross‐modal interference. Subjects showed higher accuracy of speech perception when appropriate haptic stimuli accompanied the auditory stimuli. Moreover, when presented with mismatched tactile and auditory stimuli, subjects demonstrated the fusion of the two modes. Subjects perceived /pa/ when auditory stimulus /ba/ was presented with emulating aspiration.