Hearing loss and perceptual effort: downstream effects on older adults' memory for speech.

A group of older adults with good hearing and a group with mild-to-moderate hearing loss were tested for recall of the final three words heard in a running memory task. Near perfect recall of the final words of the three-word sets by both good- and poor-hearing participants allowed the inference that all three words had been correctly identified. Nevertheless, the poor-hearing group recalled significantly fewer of the nonfinal words than did the better hearing group. This was true even though both groups were matched for age, education, and verbal ability. Results were taken as support for an effortfulness hypothesis: the notion that the extra effort that a hearing-impaired listener must expend to achieve perceptual success comes at the cost of processing resources that might otherwise be available for encoding the speech content in memory.