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

Neurobiological Mechanisms of Cognitive Decline Correlated with Brain Aging

Cognitive decline has emerged as one of the greatest health threats of old age. Meanwhile, aging is the primary risk factor for Alzheimer's disease (AD) and other prevalent neurodegenerative disorders. Developing therapeutic interventions for such conditions demands a greater understanding of the processes underlying normal and pathological brain aging. Despite playing an important role in the pathogenesis and incidence of disease, brain aging has not been well understood at a molecular level. Recent advances in the biology of aging in model organisms, together with molecular- and systems-level studies of the brain, are beginning to shed light on these mechanisms and their potential roles in cognitive decline. This chapter seeks to integrate the knowledge about the neurological mechanisms of age-related cognitive changes that underlie aging.

Aging, Functional Learning, and Inhibition

BACKGROUND/STUDY CONTEXT

The study compared the learning performance of younger and older adults in situations differing in the number of cues that could be relied on for predicting the value of a criterion. Two hypotheses were tested: one based on the assumption that the greater the inhibition effort needed in the task, the greater the difference between younger and older participants, and the other based on the fact that the context in which inhibition occurs plays a role, and consequently that the level of difficulty of the four learning conditions can be better predicted from the number of possible sets of valid cues.

METHODS

A total of 240 adults (18-90 years old) had to learn to predict the amount of drink delivered by a drink dispenser on the basis of four cues (the height of four vertical bars). The participants were randomly distributed between four experimental conditions, one valid cue, two valid cues, three valid cues, and all valid cues. The measures that were calculated for each participant under each condition included the squared mean differences between judgment and criterion as an index of performance, and cue utilizations as a test of both the learning of the strength of direct linear relationships and of inhibition.

RESULTS

The results validated the hypothesis that the level of difficulty of the four learning conditions can be better predicted from the number of possible sets of valid cues. In all conditions and in each age group, cue utilizations were direct in the first block with no feedback. Older adults discounted the nonpertinent cues as well as younger adults, whereas participants aged over 76 only succeeded under the least demanding conditions. The presence of nonpertinent cues affected the learning of direct cues, even among the younger participants.

CONCLUSION

This study shows that older adults' ability to detect (and use) valid cues in an environment that contains both valid and invalid cues is relatively well preserved. It also shows that the mere presence of invalid cues can affect the learning of direct cues, which constitutes a new result in functional learning. Future research conducted in cognitive aging should examine the role of invalid cues in functional learning.