Source Forgetting in Younger and Older Adults

• Applicant: Professorin Dr. Beatrice G. Kuhlmann
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 392884168

Remembering perceptual, spatial, and temporal details of an event is uniquely characteristic of episodic long-term memory and provides the basis for inferring the original source of remembered information (e.g., who told us something), which in turn influences our interpretation, understanding, and further use of this 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 associative memory deficit, older adults are particularly impaired in source memory compared to younger adults, much more so than in item memory. Although the cognitive processes involved in source monitoring and their neurological underpinnings have been extensively studied, little is known about forgetting of episodic source details over time. A recent proposal from cognitive neuropsychology postulates that incidental (i.e., nonintentional) forgetting processes differ between memories represented in the hippocampus (~source memory) and those represented in the neocortex (~item memory). Longer-term decay processes, operating particularly during sleep, are assumed to cause forgetting of the former whereas short-term interference processes are assumed to cause forgetting of the latter. To date, few studies have compared forgetting rates between behavioral expressions of neocortically- and hippocampally-represented memories in humans. Most of these studies relied on subjective memory experience rather than direct assessment of hippocampal memories of episodic source details. There further is a need for research comparing source forgetting between younger and older adults to test if the associative deficit extends to faster source forgetting in older age. In the proposed research project, source and item memory will be directly assessed over varying retention intervals (seconds to days) in younger and older adults. Analyses with a state-of-the-art multinomial model of source monitoring will allow separately measuring source versus item memory. In a preliminary experiment and reanalysis, I demonstrate that this model can be reparametrized to allow the direct comparison between source- and item-memory maintenance rates. I suggest an extension of this model to separate storage from retrieval processes that shall be validated in the project. Further, the project will not only aim to disentangle source and item forgetting processes but also to test moderators of source forgetting—with the goal to identify factors that promote long-term source memory, especially in older adults. Finally, broader changes in source-monitoring processes (i.e., source guessing) over time will be examined. The proposed research will contribute to a more thorough understanding of forgetting processes in episodic memory as well as of the age-related associative (source) memory deficit.

• DFG Programme: Independent Junior Research Groups
• International Connection: USA
• Cooperation Partners: Professorin Karen Mitchell; Professor Moshe Naveh-Benjamin