Ongoing projects

  • Source forgetting in younger and older adults (2018-2023)

    PI: Prof. Dr. Beatrice G. Kuhlmann; international cooperation partners: Prof. Dr. Karen Mitchell, Prof. Dr. Moshe Naveh-Benjamin

    Emmy-Noether research group funded by the German Research Foundation (DFG)

    Remembering perceptual, spatial, and temporal details of an event is uniquely characteristic of episodiclong-term memory. Based on memory for such episodic details associated with an item we can infer the original source of an item (e.g., where we saw something or who told us something), which in turn is relevant to our interpretation, understanding, and further use of the remembered information. Consequences of a failure to remember the source may range from the trivial (yet inconvenient), such as searching for an object in the wrong location, to the severe, such as trusting false information originally given by an untrustworthy source. Due to a general age-related deficit in associative memory, older adults’ source memory is more impaired than their item memory. Despite vast research on source memory, source forgetting processes have not been comprehensively studied to date. Neurocognitive theories postulate that incidental (i.e., unintentional) forgetting processes differ between memories represented in the hippocampus (i.e., source memory) and those represented in the neocortex (i.e., item memory). The former should show forgetting due to longer-term decay processes particularly occurring during sleep whereas the latter are prone to short-term forgetting due to interference. To date, only few studies have compared forgetting in behavioral measures of hippocampally versus neocortically represented memories in humans. The few studies that did rather relied on subjective reports about memory experience instead of objective assessment of the hippocampally-represented memory for episodic source details. Further, no aging studies have yet examined whether older adults’ associative deficit expands to source forgetting. In this project, we will objectively assess source and item memory in younger and older adults over retention intervals lasting from seconds to days. By employing multinomial modeling I will ensure the independent measurement of source versus item memory. In a prestudy and reanalysis, I show how this model can be reparameterized to allow for a direct comparison of the retention rates of both memory types. In addition, I propose a paradigm and model extension to separately measure storage and retrieval processes. The project will further examine moderators of source forgetting with the goal to identify factors that promote the long-term retention of source details, especially in older adults. Finally, time-related changes in source guessing will also be examined. Thereby, this project contributes to a better understanding of forgetting processes in episodic memory as well as of the associative memory deficit in older adults.

  • Context-dependent remembering in older adults (2019-2022)

    PIs: Dr. Maciej Hanczakowski, Prof. Dr. Beatrice G. Kuhlmann, Dr. Katarzyna Zawadzka

    Research grant jointly funded by the BEETHOVEN program of the German Research Foundation (DFG) and the National Science Center (NCN) Poland

    One of the most prominent features of cognitive aging is a disruption in memory processes that takes two forms: older adults struggle with accessing relevant information in memory but also experience misrecollections (false memories with high confidence). Any program of mitigating older adults’ memory deficits needs first to address the issue of how these two types of memory errors arise. The purpose of the present project is to investigate older adults’ memory deficits in terms of context-dependent remembering. Current memory models emphasize that access to particular memories requires utilizing appropriate contextual cues (e.g., physical environment in which information was stored). Thus, encoding and later using context cues benefits memory. However, using contextual cues at retrieval carries risks: inappropriate cues may result not only in failure to access relevant memories but also in metacognitive errors (‘illusion of knowing’: overconfidence in erroneous responses). We hypothesize that older adults’ memory deficits may stem from both underusing of appropriate contextual cues – due to general deficits in associative encoding of context– and overusing inappropriate contextual cues at retrieval. Across eight experiments, the current project will assess context-dependent remembering in older as compared to younger adults, testing two specific hypotheses regarding older adults’ memory deficits: 1) The hypothesis that older adults fail to fully utilize contextual cues at memory retrieval due to deficits in associative encoding such that promoting context encoding and context reinstatement will disproportionately benefit older adults’ memory; 2) The hypothesis that older adults do not appropriately appraise their memory because they tend to erroneously bind retrieval context with retrieval products, resulting in illusions of knowledge when access to familiar contextual cues is not restricted at retrieval. The project will elucidate the bases of older adults’ memory deficits. Assessing the role of context reinstatement on memory retrieval will serve to elaborate upon the state-of-the-art associative deficit hypothesis of memory impairment in older age. Assessing the role of context familiarity on metamemory will serve to extend the research on older adults’ memory to the understudied domain of appraisals of memory retrieval. The Polish team – led by Dr. Hanczakowski – has experience in research on memory and metamemory processes, particularly as related to context-dependent remembering, documented by a number of publications in leading cognitive psychology journals. The German team – led by Dr. Kuhlmann – has experience in research on older adults’ memory, also documented in a number of top publications. The joint project will combine both teams’ expertise, extending Dr. Hanczakowski’s previous research to a novel population and extending Dr. Kuhlmann’s theoretical work to a novel set of environmental factors.

  • Hierarchical MPT Modeling – Methodological Comparisons and Application Guidelines (2017-2020)

    PIs: Dr. Julia Groß, Prof. Dr. Beatrice G. Kuhlmann

    Scientific network funded by the German Research Foundation (DFG)

    Multinomial processing tree (MPT) models are stochastic measurement models for categorical data. They allow investigators to explain participants’ behavioral responses in experimental tasks by estimating the contribution of different latent cognitive processes that underlie these responses. MPT models have been developed for a variety of psychological paradigms (e.g., memory, judgment and decision making, reasoning, attitude measurement) and have gained popularity in the last decade. They are increasingly applied to study various different populations, for example in clinical and developmental research. Traditionally parameters are estimated for participant or item groups. This aggregated MPT-approach is based on the assumption that there are no substantial differences between participants or items (parameter homogeneity). This assumption is likely violated in most applications, which may have severe consequences (e.g., biased parameter estimation and model-fit statistics). The reliability and validity of published MPT results must thus be questioned. For real empirical data, the type, extent, and conditions of these biases have not yet been systematically investigated. One of the two objectives of this network is thus a large-scale reanalysis of published MPT data from different paradigms. However, fitting MPT models to individuals typically results in unreliable estimates and is thus not an alternative for scientists who are interested in populations with inherent large heterogeneity or in interindividual differences (e.g., correlational analyses). Thus, hierarchical variants of MPT modeling (h-MPT) have been developed as a compromise (e.g., Klauer, 2010; Smith & Batchelder, 2010). They account for parameter heterogeneity by specifying a population-level distribution across individual participants/items. H-MPT models seem a promising and useful development of common practice but their application is challenging. Different h-MPT approaches rely on different statistical approaches and assumptions; there are various evaluation criteria for the estimation process. In addition, h-MPT modeling requires substantial knowledge and programming skills, which prevents its widespread application in psychological research. The second objective of the network is thus to establish general h-MPT application guidelines. We are confident that the combination of high methodological expertise with empirical application breadth accomplished by this network can promote the application of h-MPT modeling in psychological research.

    Completed projects

  • Age-related differences in episodic memory: The role of test format adaptivitity and options for support (2017-2020)

    PI: Prof. Dr. Beatrice G. Kuhlmann

    funded by the Juniorprofessor-Program of the State Ministry of Baden-Wuerttemberg for Sciences, Research and Arts

    Across three years, eight comprehensive laboratory experiments will examine test-format adaptivity (i.e., the adaptation of encoding to the expected memory test difficulty) in older adults’ episodic memory. Based on prior research revealing encoding strategy production and utilization deficiencies and attention deficits in older adults, restrictions in older adult’ test-format adaptivity are expected. Empirical support of this hypothesis implies that age-group differences in episodic memory are overestimated when a free recall test is expected, a result of widespread consequence for research on cognitive aging as well as clinical memory assessments. Further, this project will explore options for supporting test-format adaptivity in older adults.