Schedule of Events | Symposia

Effect of place of articulation and phonemic restoration on the Audio-Visual Time Flow Illusion

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Achint Sharma¹, Heather Bortfeld¹, Antoine J Shahin¹, Kristina C Backer¹; ¹University of California, Merced

The Audiovisual Time-Flow Illusion (AVTFI) demonstrates that the auditory domain sets the pace of processing of the corresponding visual speech during AV speech perception. When the auditory speech is temporally altered (i.e., by deleting segments or adding silent pauses), individuals perceive a “skip” or “pause” in the visual signal despite the manipulation being only in the auditory stream. The present study investigated whether the place of articulation (POA) of the temporally altered phoneme results in a change in this illusory perception and whether AVTFI is tied to the phonemic restoration (PR) mechanism. We contrasted AVTFI perception for phonemes with a discernable (e.g., /b/, /p/) versus indiscernible (e.g., /g/, /k/) POA in 30 young adults. Additionally, we investigated the effect of POA on the PR illusion, whereby the same 30 participants were presented with AV speech stimuli in which phonemes with a discernable or indiscernible POA were removed and replaced with noise. Participants reported whether the speech sounded continuous through the noise. We hypothesized that individuals would experience stronger AVTFI for phonemes with indiscernible versus discernible POA, and AVTFI would be inversely correlated with PR, as stronger phonemes with discernible POA and PR are likely to reduce the perception of a temporal change. First, we observed similar levels of AVTFI perception regardless of POA discernibility. Second, participants showed enhanced PR for phonemes with a discernable POA, but there were no significant across-subject correlations between AVTFI and PR illusory perception, suggesting that these illusions rely on different mechanisms.

Topic Area: PERCEPTION & ACTION: Multisensory