Some limits on encoding visible speech and gestures using a dichotic shadowing task

Visible speech and gestures are two forms of available language information that can. be used by listeners to help them understand the speaker's meani ng. previous research has shown that older adults are particularly dependen t on visible speech, yet seem to profit less than younger adults from the s peaker's gestures. To understand how visible speech and gestures are used w hen listening becomes difficult, the authors conducted an experiment with a dichotic shadowing task. The experiment examined how accurately participan ts could shadow the right- or left-ear input when instructed to attend sele ctively to a particular ear and whether performance benefited from visual i nput. The results indicate that older adults' shadowing performance was una ffected by visible speech and gestures. Younger adults did benefit by both visible speech and gestures. Thus, under extremely attention-demanding list ening conditions, older adults are unable to use a compensatory mechanism f or encoding visual language.