Adult Age Differences in the Use of Conceptual Combination as an Associative Encoding Strategy.

Heather D Lucas,Resh S Gupta,Ryan J Hubbard,Kara D Federmeier

doi:10.3389/fnhum.2019.00339

Abstract

It is well-established that aging impairs memory for associations more than it does memory for single items. Aging also impacts processes involved in online language comprehension, including the ability to form integrated, message-level representations. These changes in comprehension processes could impact older adults’ associative memory performance, perhaps by reducing or altering the effectiveness of encoding strategies that encourage semantic integration. The present study examined age differences in the use of a strategy termed conceptual combination, which involves integrating two words (e.g., “winter” and “salad”) into a single concept (“a salad for winter”). We recorded ERPs while participants studied unrelated noun pairs using a strategy that either did or did not encourage conceptual combination. We also varied the concreteness of the first noun in each pair in order to measure compositional concreteness effects, or ERP differences at the second noun due to the concreteness of the first noun. At the first nouns, older adults showed word-level concreteness effects that were similar to those of younger adults. However, compositional concreteness effects were diminished in older adults, consistent with reduced semantic integration. Older adults’ associative memory performance was better for word pairs studied during the conceptual combination task versus the non-combinatory encoding task; however, the magnitude of the age-related associative memory deficit did not differ between tasks. Finally, analyses of both memory accuracy and trial-by-trial ratings of perceived combination success suggested that older adults had disproportionate difficulty applying the conceptual combination strategy to word pairs that began with abstract nouns. Overall, these results indicate that changes to integrative language processing that occur with age are not independent of – and may sometimes exacerbate – age-related memory decline.

Highlights

A hallmark of the typical aging process is a reduced ability to learn and remember new information
Summary and Age Comparisons In summary, compositional concreteness effects in older adults occurred in the N400 window, where they took the form of more negative ERPs to abstract versus concrete words
This pattern is similar to the N400 compositional concreteness effects observed in young adults in Lucas et al (2017), and, a comparison of the mean difference in N400 amplitudes between concretely-modified and abstractly-modified W2s between age groups was non-significant [F(1, 46) = 0.12, p = 0.73]

Summary

Introduction

A hallmark of the typical aging process is a reduced ability to learn and remember new information. Memory for associative or relational information (e.g., arbitrary pairings or groupings of stimuli, such as face-name pairings) is susceptible to age-related decline, whereas the ability to remember single items is relatively spared (for a recent meta-analysis, see Old and Naveh-Benjamin, 2008). Item memory has been linked to the surrounding medial temporal lobe (MTL) cortex, the perirhinal cortex (e.g., Davachi, 2006), which is less susceptible to changes with age (Dickerson et al, 2009)

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Discussion

Conclusion