The effects of age on category learning and prototype- and exemplar-based generalization.

Abstract

The need to learn new concepts and categories persists through the lifespan, yet little is known about how aging affects the concept learning and generalization. Here, we trained young and older adults to classify typical and boundary category members, and then tested category generalization to new stimuli. During training, older adults had increased difficulty compared to young adults learning category labels for boundary items, but not typical items. At test, categorization performance that included new items at all levels of typicality was comparable across age groups, but formal categorization models indicated that older adults relied to a greater degree on generalized (prototype) category representations than young adults. These findings align with the proposal that older adults are able to form category representations based on central tendency even when they have difficulty learning and remembering individual category members. More broadly, the results contribute to our understanding of multiple categorization strategies and the limited strategy flexibility in older adults. They also highlight how reliance on preserved cognitive functions may sometimes help older adults maintain performance. Public Significance StatementWe show that older adults are more likely than young adults to form on abstract category representations, which can support successful generalization even in the presence of age deficit in initial learning. These findings suggest that older adults can sometimes achieve the comparable categorization performance as young adults by adopting a strategy that does not rely strongly on memory for individual items.

Coherent category training enhances generalization in prototype-based categories.

“…That high coherence training produced highly generalizable category knowledge in our study is also consistent with prior work suggesting that stability and consistency in input facilitate broad category knowledge (Carvalho et al, 2019;Horst et al, 2011), and that learning from an easier training set can facilitate later categorization of more difficult items (Edmunds et al, 2019). Finally, the findings also align with our prior aging study showing that when training contains a mixture of typical and atypical items, older adults have difficulty learning the atypical items but their successful acquisition of typical items is sufficient to support subsequent generalization at levels comparable to young adults (Bowman et al, 2022).…”

Successful generalization of conceptual knowledge after training to remember specific events

“…Here, we hypothesized there would be a difference in generalization strategy between classification and paired-associate learning groups. Specifically, we used prototype and exemplar models of categorization, both of which can provide good fits to behavior (Bowman et al, 2022;Heit, 1992;Hintzman, 1984;Nosofsky, 1986;Nosofsky et al, 1994;Posner & Keele, 1968) and neural activity Bowman & Zeithamova, 2018;Mack et al, 2013). We predicted an increase in reliance on exemplars after paired-associate learning emphasizing memory for individual stimuli, but the results were mixed in that regard.…”

“…However, we also observed a positive relationship among prototypists, although we expected no relationship (suggesting parallel representations) or a negative relationship (suggesting trade-off). One possibility is that even among prototypists, memory for specific exemplars contributes to generalization decisions (Bowman et al, 2022), as would be expected in both specific and generalized representations are formed and available to inform judgments. Another possibility is that the quality of specific memories constrained the quality of generalization representations in the current study--even though this is not the case in general (Ngo et al, 2021).…”

Older Adults Select Different But Not Simpler Strategies Than Younger Adults in Risky Choice

“…In terms of age-related cognitive decline, for instance, it has been concluded that older adults rely on simpler cognitive strategies (e.g., in reinforcement-learning tasks and working-memory tasks; Chevalère et al, 2020;Eppinger et al, 2013;Ruel et al, 2023) and make more errors (Tymula et al, 2013) than younger adults. Moreover, older adults show less flexibility in adjusting cognitive processes to the situation (Bolenz et al, 2019;Bowman et al, 2022;Mata et al, 2007;Pachur et al, 2009) and they may make different trade-offs between the complexity of a cognitive process and its potential benefits (Ruel et al, 2021). These changes due to age-related cognitive decline might affect the mental operations selected by a decision maker when making risky choices.…”