The overall aim is to understand the cognitive and neural bases of implicit probabilistic associative learning and how these vary with adult age. Learning is said to be implicit when people acquire information about structural regularities without intending to learn or becoming aware of what they have learned. Implicit learning is likely more important for adapting to the world than its explicit/declarative counterparts, particularly in later adulthood when little time is spent in formal schooling, a setting which emphasizes explicit learning. Nonetheless, the aging of implicit learning has been studied much less, perhaps because age-related deficits have sometimes been small or non-existent. This apparent sparing creates a paradox: Associative implicit learning calls on neural systems that show structural and functional declines in healthy aging, and so how would older people be relatively good at it? This is addressed by adopting themes from two research areas: Cognitive neuroscience provides evidence that two interactive learning systems--one based on the Medial Temporal Lobe (MTL) and the other based on the striatum--can contribute to such learning. The cognitive neuroscience of aging provides evidence that one of these neural systems is more sensitive to aging than the other, and that older brains often do the same task differently from younger brains. These themes lead to two hypotheses. First, that implicit probabilistic associative learning is not spared in healthy aging, but rather is characterized by persistent age-related learning deficits that can be detected as early as middle-age. These deficits are more pronounced as practice progresses, and cannot be attributed solely to age-related deficits in general processing resources. Rather, they reflect a fundamental deficit in the function of the striatal learning system. Second, the relative balance of these systems changes with age;early in training the MTL system dominates in both young and old adults, but as training proceeds the young adults come to rely on the striatal system, whereas the old continue to rely on their relatively intact MTL system. This enables old adults to maintain near- young levels of performance very early in training, but not later. These hypotheses will be tested by conducting behavioral and neuroimaging studies, using a recently developed triplets-learning-task (TLT).
Aim 1 is to characterize age differences in implicit probabilistic associative learning.
Aim 2 is to test behavioral implications for aging of the interactive systems hypothesis, and Aim 3 is to characterize the neural bases of implicit probabilistic associative learning in young and old adults, and relate them to behavior.
These aims are important for fostering successful aging and independent living, because implicit associative learning is needed for adapting to new people, environments, and technologies, as well as for relearning skills after injury.

Public Health Relevance

Understanding the cognitive and neural bases of implicit forms of learning, and how to maximize such learning at all ages, is key to fostering successful aging, because implicit learning is essential for adapting to new environments and people, and for recovering function after injury and stroke. Further, identifying how implicit learning is affected by healthy aging will ultimately help to distinguish healthy from pathological aging (e.g., Alzheimer's disease). To the extent that implicit learning is spared in pathological aging, it can be the basis for remediation, thereby extending independent living, and improving the quality of life of patients and caregivers.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Research Project (R01)
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Special Emphasis Panel (ZRG1-CP-D (02))
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Wagster, Molly V
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Georgetown University
Schools of Arts and Sciences
United States
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Stillman, Chelsea M; Howard Jr, James H; Howard, Darlene V (2016) The Effects of Structural Complexity on Age-Related Deficits in Implicit Probabilistic Sequence Learning. J Gerontol B Psychol Sci Soc Sci 71:212-9
Stillman, Chelsea M; You, Xiaozhen; Seaman, Kendra L et al. (2016) Task-related functional connectivity of the caudate mediates the association between trait mindfulness and implicit learning in older adults. Cogn Affect Behav Neurosci 16:736-53
Schwab, Jessica F; Schuler, Kathryn D; Stillman, Chelsea M et al. (2016) Aging and the statistical learning of grammatical form classes. Psychol Aging 31:481-7
Seaman, Kendra L; Stillman, Chelsea M; Howard, Darlene V et al. (2015) Risky decision-making is associated with residential choice in healthy older adults. Front Psychol 6:1192
Negash, Selam; Kliot, Daria; Howard, Darlene V et al. (2015) Relationship of contextual cueing and hippocampal volume in amnestic mild cognitive impairment patients and cognitively normal older adults. J Int Neuropsychol Soc 21:285-96
Seaman, Kendra L; Howard, Darlene V; Howard Jr, James H (2015) Adult age differences in subjective and objective measures of strategy use on a sequentially cued prediction task. Neuropsychol Dev Cogn B Aging Neuropsychol Cogn 22:170-82
Gamble, Katherine R; Lee, Joanna M; Howard Jr, James H et al. (2014) Effects of priming goal pursuit on implicit sequence learning. Exp Brain Res 232:3635-43
Gamble, Katherine R; Cummings Jr, Thomas J; Lo, Steven E et al. (2014) Implicit sequence learning in people with Parkinson's disease. Front Hum Neurosci 8:563
Stillman, Chelsea M; Coane, Jennifer H; Profaci, Caterina P et al. (2014) The effects of healthy aging on the mnemonic benefit of survival processing. Mem Cognit 42:175-85
Gamble, Katherine R; Howard Jr, James H; Howard, Darlene V (2014) Not just scenery: viewing nature pictures improves executive attention in older adults. Exp Aging Res 40:513-30

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