Do you often feel overwhelmed by incoming information and notice you forget things like a shopping list after hearing the sports results? It turns out this ordinary forgetfulness may be an essential part of how we learn.
New research from the University of Glasgow’s Institute of Neuroscience and Psychology, published in Current Biology, shows that the brain’s tendency to let some newly formed memories remain unstable — or to “forget” them temporarily — plays a critical role in transferring skills and experiences to new situations.
The researchers examined how memory instability affects the ability to apply learning across different tasks. They found that when a newly formed memory is unstable, it can interact with other recent memories and produce a higher-level, abstract representation that supports transfer of learning. By contrast, when memories are stabilised or consolidated, transfer across tasks is blocked.
In their experiments participants learned one task at 9am and then quickly learned a second one; they were retested on the first task 12 hours later. The two tasks were deliberately different in form: one was a repeating 12-word sequence and the other was a motor sequence — a set of finger movements similar to tapping a PIN on an ATM.
Learning moved between the tasks in both directions. For example, practicing the word list improved performance when participants later learned the motor sequence, and practicing the motor sequence improved later word-list learning. Importantly, what transferred was not memory for the specific words or exact movements, but a high-level relationship or structural pattern shared by the two tasks. This transfer occurred only when the initial memory remained unstable.
Professor Edwin Robertson from the Centre for Cognitive Neuroimaging explains that an unstable memory prevents learning from becoming rigidly tied to a single task and instead allows the learning to be applied flexibly. When the team deliberately stabilised the initial memory using several established methods, transfer to the subsequent task disappeared, showing the causal role of instability in promoting transfer.
The researchers monitored performance across multiple practice blocks. They saw clear improvements in motor skill learning when the earlier word list and the later motor sequence shared a similar abstract structure. These improvements were diminished or absent whenever the initial memory had been stabilised before the second task.
Professor Robertson adds that an unstable memory creates a brief window in which memories can “communicate,” allowing the brain to build a higher-level representation. This abstract representation captures relationships among elements rather than the elements themselves, and it is this representation that supports flexible transfer of knowledge between diverse tasks.
The findings also align with neural evidence: the brain regions implicated in memory instability overlap with areas involved in forming memory frameworks and abstract representations. That overlap suggests a mechanistic link between memory instability and the brain’s ability to extract and generalise patterns.
Funding: The study received support from the National Institutes of Health and the National Science Foundation.
Source: University of Glasgow
Image credit: Image adapted from the University of Glasgow press release
Original research: “Unstable Memories Create a High-Level Representation that Enables Learning Transfer” by Neechi Mosha and Edwin M. Robertson, Current Biology. Published online December 17, 2015. doi:10.1016/j.cub.2015.11.035
Abstract
Unstable Memories Create a High-Level Representation that Enables Learning Transfer
Highlights
• Learning can transfer from a word-list memory task to a motor-skill task and vice versa.
• Transfer occurs only when the initial memories remain unstable.
• Only shared, high-level features of the tasks are transferred, not the individual elements.
• High-level, abstract representations are formed when memories are unstable.
Summary
After initial acquisition, a memory can be unstable and vulnerable to interference. The functional role of this instability has been unclear. The current study tests whether instability enables communication between recently acquired memories, allowing learning in one task to influence acquisition in another. Using paired word-list and motor-sequence tasks, the authors found bidirectional transfer of learning that reflected abstract relationships rather than element-specific knowledge. Measures of memory instability predicted the extent of transfer. When the initial memory was stabilised by established procedures, transfer was consistently eliminated. These results indicate that memory instability supports the formation of a high-level representation that enables learning to generalise across diverse tasks, revealing an important adaptive function of forgetting.