Formal Modeling in Research on Episodic Memory and Aging

Abstract For about forty years, age-related differences in episodic-memory tasks have been a major focus of the growing field of cognitive-aging research. Most theoretical approaches invoked to explain such differences are based on a vast research literature consisting mostly of empirical studies, and making relatively little use of formal models of memory. We argue that formal modeling is an invaluable tool in meeting the unique theoretical and methodological challenges of the field. We provide an overview of formal models that address core theoretical issues in memory-and-aging research. These issues are age differences in encoding and retrieval processes, age differences in memory for contextual information, and the interplay of memory with judgment and decision processes. We also discuss areas that could benefit from further formalization. Formal Modeling in Research on Episodic Memory and Aging Older adults typically show lower performance in episodic-memory tasks as compared to younger adults (for reviews, see Light, 2000; Zacks, Hasher, & Li, 2000). The area of cognitive-aging research has grown rapidly in recent years, with one of its chief goals to understand age-related differences in episodic-memory performance. In this article, we argue that formal modeling can help meet this goal. We give a brief overview of the field of aging and episodic memory before reviewing how formal models have been used and how they could further contribute to theoretical advancement in the field. Theories, Methods, and Major Findings of Research on Episodic Memory and Aging Younger adults usually outperform older adults in episodic-memory tasks such as recall and recognition (for a meta-analysis, see Verhaeghen, Marcoen, & Goossens, 1993; for qualitative reviews, see Craik, 2000; Light, 2000; Zacks at al., 2000). In recall tasks, older adults reproduce less of the studied information and commit more intrusion errors than younger adults. In recognition tasks, older adults "are more likely than younger adults to accept as old never-presented items [called foils or lures], especially if those lures share a conceptual, schematic, or perceptual resemblance to the presented items" (Zacks et al., 2000, p. 31 1). A number of theories have been proposed to account for these findings. Among the currently most popular explanations are those that attribute the pattern of age differences to deficits in speed of processing (e.g., Salthouse, 1996), ability to inhibit irrelevant information (e.g., Hasher & Zacks, 1988), working-memory capacity (e.g., Light, Zelinski, & Moore, 1982; Salthouse, 1992), or attentional capacity (e.g., Salthouse, Fristoe. Lineweaver, & Coon, 1995; Anderson, Craik, & Naveh-Benjamin, 1998). Other approaches have sought to locate age-related deficits in encoding or retrieval processes (e.g., Rabinowitz et al., 1982; Schonfield & Robertson, 1966), or attributed age differences in episodic-memory performance to older adults' deficits in processing contextual information (e.g., Bayen, Phelps, & Spaniol, 2000; Kliegl & Lindenberger, 1993; Light et al., 1992), or deficits in recollective processes (e.g., Jennings & Jacoby, 1993). Neurobiological work has suggested that agerelated declines in memory are linked to structural changes in the prefrontal cortex (e.g., Raz et al., 1997) or to changes in brain chemistry (e.g., Volkow et al., 1998). None of these cognitive-aging theories can, in their current form, explain all the data in the literature. The main focus of this paper is on the experimental tradition within cognitive-aging research. This tradition has borrowed theories and experimental methods from the episodic-memory literature in cognitive psychology, which has typically dealt with younger-adult data. This literature is characterized by a higher degree of formalization than the memory-and-aging literature. Thus far only few of the formal models of memory developed in cognitive psychology have been utilized in cognitive-aging research. …