FIG. 1.

(Color online) Stimuli and task design. (A) Spectrogram of the /da/-/ga/ continuum. Each of the seven acoustic tokens of the morphed speech continuum was overlaid onto a video of either a prototypical /da/ (Tk 1–3) or /ga/ (Tk 4–7) (Nath and Beauchamp, 2012; Mallick et al., 2015). We intended to further warp (bias) participants' auditory perceptual space to one or the other end of the speech continuum with visual cues of the talker. (B) Single trial time course. After a brief orienting screen (+), participants rapidly identified whether they perceived each audio(visual) token as a “da” or “ga” via computer keypress. Speech stimuli were presented in four different blocks which varied in the number of sensory cues from the talker and the presence/absence of acoustic noise interference: A, A+noise, AV, AV+noise.