Audiovisual interaction on the perception of frequency glide of linear sweep tones

Audiovisual interaction was found on the perception of frequency glide of linear sweep tones. The auditory and visual stimuli were designed to simulate the formant trajectories of the syllables that induced the McGurk effect. Linear sweep tones were used for the auditory stimuli. For the visual stimuli, moving spheres were used. The frequency glide was differently perceived depending on the sphere motion. The experimental results showed that the identification of linear frequency glide was significantly different between with and without the motion of the visual stimuli. An interesting result was that frequency-glide was perceived for a steady tone presented with the enlarging sphere. Enlarging and shrinking motion of the sphere had strongest effect to enhance the perception of frequency glide. However, linear movement of the sphere did not show clear audiovisual interaction.