Fluidity in the perception of auditory speech: Cross-modal recalibration of voice gender and vowel identity by a talking face.

Humans quickly adapt to variations in the speech signal. Adaptation may surface as , a learning effect driven by error-minimisation between a visual face and an ambiguous auditory speech signal, or as , a contrastive aftereffect driven by the acoustic clarity of the sound. Here, we examined whether these aftereffects occur for vowel identity and voice gender. Participants were exposed to male, female, or androgynous tokens of speakers pronouncing /e/, /ø/, (embedded in words with a consonant-vowel-consonant structure), or an ambiguous vowel halfway between /e/ and /ø/ dubbed onto the video of a male or female speaker pronouncing /e/ or /ø/. For both voice gender and vowel identity, we found assimilative aftereffects after exposure to auditory ambiguous adapter sounds, and contrastive aftereffects after exposure to auditory clear adapter sounds. This demonstrates that similar principles for adaptation in these dimensions are at play.