The current study addresses the changing use of audio and visual cues in audio-visual speech perception during adulthood by testing young and middle-aged adults using stimuli with incongruent audio-visual consonants. Young adults gave more audio responses and fewer visual responses than middle-aged adults. Results show no age differences in auditory or visual sensitivity. The discrepancy in use of modalities is therefore concluded to most likely be due to middle-aged adults being more flexible perceivers than young adults resulting from more audio-visual speech experience