Memory updating in animals
Reconsolidation theory proposes that retrieval of existing memory traces causes them to destabilize, triggering a transient molecular restabilization (“reconsolidation”) process during which they are open to modification (1, 2).
If reconsolidation enables memory modification in humans, it could have profound theoretical (3), clinical (4), and ethical (5) implications.
On day 1, participants used a computer keyboard to repeatedly tap a simple sequence of on-screen digits (e.g., 41342).
Speed and accuracy improvements were observed as participants learned this initial (“Old”) sequence.
However, demonstrating reconsolidation-mediated memory updating in humans has proved particularly challenging.
In four direct and three conceptual replication attempts of a prominent human reconsolidation study, we did not observe any reconsolidation effects when testing either procedural or declarative recall of sequence knowledge.
On the other hand, amnesia has been attributed to mechanisms operating during trace retrieval that temporarily modulate trace-dependent performance without necessarily influencing the underlying memory trace [e.g., “response competition” (22); “cue-dependent forgetting” (23); “state-dependent retrieval” (24); “context-dependent forgetting” (25)].
These retrieval deficit accounts can explain experimentally induced amnesia without invoking claims about physical trace disruption that cannot be directly observed.
We conducted a replication battery (31) consisting of both “direct replications” (32) that followed the methodology of the original study as closely as possible, and “conceptual replications” (33) that manipulated key task parameters to explore the broader validity of the reconsolidation-updating theory.
These findings suggest that the considerable theoretical weight attributed to the original study is unwarranted and that postretrieval new learning does not reliably induce human memory updating via reconsolidation.
Reconsolidation theory proposes that retrieval can destabilize an existing memory trace, opening a time-dependent window during which that trace is amenable to modification.
On day 2, participants in the Reminder group ( = 16) practiced the Old Sequence immediately before learning a New Sequence.
The No-Reminder group did not practice the Old Sequence before new learning.
Search for memory updating in animals:
Therefore, it would appear that the accuracy impairment in the Reminder group was contingent on the time-dependent interaction of the reminder and intervention as demonstrated in similar nonhuman animal studies (1) and widely accepted as evidence for reconsolidation (2, 4, 6). However, from the perspective of the aforementioned storage–retrieval debate (18), this interpretation should be viewed with caution, especially as retrieval deficit explanations were not explored.