The effect of perceptual cues on inhibiting irrelevant information in older adults using a list-learning method

BACKGROUND/STUDY CONTEXT: The inhibitory deficit hypothesis (Hasher & Zacks, 1988 , The Psychology of Learning and Motivation: Advances in Research and Theory, 22, 193-225) suggests that older adults are more susceptible to interference from irrelevant information because of age-related declines in inhibitory ability. Reading comprehension tasks have found that this deficit can be overcome by salient perceptual cues used to accentuate relevant information (Carlson, Hasher, Connelly, & Zacks, 1995 , Psychology and Aging, 10, 427-436). This study examined the ability of older adults to use perceptual cues to aid inhibition in list-learning tasks.

Sixteen younger (18-24 years of age) and sixteen older (62-79 years of age) adults were asked to remember/ignore presented items based on a pre- or posttrial perceptual cue (i.e., red or green font designated item relevance before or after each trial). The to-be-ignored stimuli could be pseudo-words or words taken from the same word pool as the relevant items. A repeated measures analysis of variance (ANOVA) was done to examine age-related differences in recognition of to-be-remembered items.

As expected, younger adults showed better performance than older adults when item relevance was designated posttrial. Most importantly, pretrial perceptual cues eliminated age-related differences in performance when the task-irrelevant stimuli were pseudo-words, but not when they were words from the same word pool as the task-relevant stimuli.

The results suggest that perceptual cues are not reliably sufficient to overcome inhibitory deficits in older adults, and that older adults may continue to process irrelevant information, leading to declines in task performance. This warrants further investigation regarding the extent to which relevant and irrelevant items must be distinguishable, perceptually or semantically, in order to aid inhibitory ability in older adults.