Projects

Does reactivation reliably trigger episodic memory change? The reliability of reconsolidation effects in humans has been called into question, challenging the prevailing interpretation of post-retrieval plasticity effects (e.g., Hardwicke, Taqi, & Shanks, 2016). Together with my graduate student Iiona Scully and my colleague Lucy Napper, we critically assessed the evidence for human episodic memory reconsolidation and its potential moderators using a meta- analytic approach. Our results indicate that when episodic memories are reactivated, they indeed become susceptible to physiological and behavioral interference manipulations. These manipulations alter the amount of information that can later be retrieved from the original learning event. This effect is stronger for remote in comparison to recent memories, supporting the view that even distant memories can return to a plastic state. Additionally, new learning following reactivation reliably updates the original memory with new content. These findings support a dynamic view of long-term memory, showing that memories can be changed long after they were acquired. 

Scully, I., Napper, L., & Hupbach, A. (2017). Does reactivation trigger episodic memory change? A meta-analysis. Neurobiology of Learning and Memory, 124, 99-107.

When does new information lead to memory updating vs. trace separation? My research on reconsolidation has identified conditions that promote and prevent memory updating, and thus has shed light on the fundamental question of how a cognitive system deals with new information that is encountered after memory reactivation – either the new information becomes part of an entirely new episodic memory or the new information is used to update the original, existing memory. This is not meant as a dichotomy - in most of my studies, both processes were at play in that certain elements of the new information became integrated into the original memory while others became part of a new episodic memory. However, several factors seem to favor one process over the other, including reinstatement of mental and spatial context (Hupbach et al., 2008, 2011), memory strength (Hupbach, 2015), explicit instructions (Hupbach, 2013), and the level of competition between old and new information (Hupbach, 2011). In collaboration with my graduate student Iiona Scully, we brought several of these factors together in a large-scale study to assess how different reactivation procedures interact with post-reactivation manipulations. We found that direct memory reactivations in the form of a memory test or a re-study session strengthen memory and prevent updating, whereas indirect memory reactivations such as encountering previously studied items in an unrelated task make memories susceptible to retroactive interference and intrusions from competing memories (Scully & Hupbach, 2020). 

Scully, I. & Hupbach, A. (2020). Reactivation strength and memory compatibility determine the effects of new learning on reactivated memories. Hippocampus, 30, 806– 814. 

Changing attitudes and first impressions through reconsolidation I am particularly excited about a new direction in my lab in which I use my expertise in memory reconsolidation to see how rather consequential memories can be changed, namely attitudes toward others. Here I assume that attitudes are learned associations between attitude objects and affective responses and that they are stored in memory just like any other form of knowledge (Fazio, 2007). Therefore, I predict that, just like other forms of memory, reactivation of attitudes will induce plasticity. In a collaborative project with Gordon Moskowitz from Lehigh, Melissa Fergusson from Yale, Amy Krosch from Cornell University, and Irmak Olcaysoy-Okten from the Florida State University, we are asking whether first impressions that are notoriously difficult to update could be changed in a long-lasting manner by interventions that target memory reconsolidation processes. This type of updating promises to alter existing traces in memory instead of merely adding novel traces when new contradictory information is observed. This project combines behavioral, neuroimaging, and computational approaches to explore the mechanisms underlying updating of implicit and explicit impressions and is funded by a grant from NSF. In a first study, we found evidence for impression updating in both superficial and real-world contexts when the newly provided information contradicted previous positive impressions and at the same time was highly diagnostic of negative characteristics of the person. 

Development of intentional forgetting 

Most prior studies failed to observe DF effects in preschool children. This has been attributed to the late development of inhibitory control processes that mediate DF (Aslan, Zellner, & Bäuml, 2010). Two of my undergraduate honors students and I explored the alternative possibility that the inability of children to fully grasp the study material and task instructions accounts for the apparent absence of DF in children. In two studies, we found reliable DF effects in 4- and 5-year-olds with concrete everyday objects and simplified test instructions, such as telling children to “empty their heads of the previous objects to make room for new ones” (Hupbach, Weinberg, & Shiebler, 2018). We attribute these forgetting effects to mental context changes rather than inhibitory processes. Importantly, such forgetting has beneficial effects on new learning, and could therefore be strategically implemented in preschool learning programs. 

Hupbach, A., Weinberg, J., & Shiebler, V. (2018). Forget-me, forget me not. Evidence for directed forgetting in preschoolers. Cognitive Development, 45, 24-30. 

Does intentional forgetting cause long-lasting changes in the accessibility of memories? 

Surprisingly few studies have examined the long-term effects of intentional forgetting, despite their potential relevance for educational and clinical practice. Long-term effects could reflect differences in consolidation (i.e., long-term storage) between forget- and remember-cued information. Consolidation processes are needed to transform initially labile into stable long-term memory traces. 

While originally conceptualized as a “conservation” process operating equally on all newly encoded information, more recent studies suggest that information that has been “tagged” as relevant during encoding is preferentially selected and strengthened during consolidation. If the cues to forget or to remember act as tags signifying the relevance of the encoded information for the future, List 1 should be preferentially consolidated in the remember condition, resulting in long-term DF effects. This prediction was supported in a study in my lab (Hupbach, 2018); participants who had been told to remember List 1 showed enhanced memory after a 24-hour interval in comparison to participants who had been told to forget List 1. Furthermore, evidence for a selective sleep-dependent enhancement was found: When 12-hr delays were implemented which participants either spent awake during the day or asleep during the night, sleep only enhanced List 1 memory for participants that had been told to remember List 1, but not for participants that had been told to forget it. We recently replicated the long-term effects of intentional forgetting in a study on memory for behaviors which is described in more detail in the next paragraph (Scully & Hupbach, 2020). 

Hupbach, A. (2018) Long-term effects of directed forgetting. Memory, 26, 321-329.
Scully, I. D. & Hupbach, A. (2020). Directed forgetting affects how we remember and judge other people. Journal of Applied Research in Memory and Cognition, 9, 336-344. 

Intentional forgetting in the social domain 

Does intentional forgetting have consequences beyond the laboratory? I am eager to understand how memory impacts social interactions, and I have begun exploring whether people can intentionally forget behaviors of others, and how such forgetting affects how others are perceived and evaluated. In one study, my graduate student Iiona Scully and I showed that when participants were instructed to forget neutral and negative behaviors of a fictional character, memory for the behaviors was reduced in comparison to a remember condition. Importantly, the fewer negative behaviors were recalled, the warmer and less dominant the character was judged. This shows that intentional forgetting can have long-lasting consequences for memory and explicit judgments of others (Scully & Hupbach, 2020). 

In a separate project, my collaborator Irmak Olcaysoy Okten (Florida State University), and I are assessing the potential effects of intentional forgetting on impression formation. In a series of experiments, we showed that although participants can deliberately forget trait-implying behaviors, the traits that were inferred from these behaviors prevail in memory (Hupbach, Olcaysoy Okten, & Horn, 2022). We are currently following up on this effect using alternative trait assessments to explore the precise conditions under which implied traits bias the perception of others. One of the long-term goals for this project is to identify conditions that would permit updating of first impressions through targeted forgetting and new learning. 

Scully, I. D. & Hupbach, A. (2020). Directed forgetting affects how we remember and judge other people. Journal of Applied Research in Memory and Cognition, 9, 336-344.

Hupbach, A., Olcaysoy Okten, I., & Horn, P. (2022) Intentional forgetting in the social domain: forgetting behaviors but not inferred traits. . Journal of Applied Research in Memory and Cognition, 4, 522-533.