The New Theory of Disuse is a theory about **memory function**. Bjork and Bjork (1992) suggested that there are two ways to measure **memory strength**: storage strength and retrieval strength. - **Storage strength** (SS) refers to how well something is learned, that is, how much the mental representations under consideration are integrated and entrenched with other memory representations. This covers both declarative and procedural knowledge. - **Retrieval strength** (RS) refers to how easily something can be accessed and activated from memory. This crucially depends on the momentarily available internal and external (i.e., mental and environmental) [[Memory involves the stages of encoding, consolidation, and retrieval|cues]]. This distinction is related to earlier work which distinguished between **habit strength** and **response strength**, which correspond to Bjork and Bjork's SS and RS, respectively.^[Brown et al., 2014] More broadly, Bjork and Bjork's work (1992) responded to Edward Thorndike's **laws of use and disuse**, which according to the [American Psychological Association](https://dictionary.apa.org/law-of-use) posit that the more an association is used, the stronger it becomes (law of use), and conversely, the less an association is used, the weaker it becomes (law of disuse). In other words, without continuous use, memories will decay and be lost. Newer research subsequently contradicted these laws and showed that memories aren't lost, but rather become inaccessible over time if they aren't used. Additionally, the **storage capacity** of human memory has been found to be virtually unlimited, at least for practical purposes. This is in stark contrast with our **retrieval capacity**, which seems severely limited. The **New Theory of Disuse** incorporates these findings from empirical research.^[Bjork & Bjork, 1992] Based on the idea that our storage capacity is virtually unlimited, the theory assumes that **storage strength (SS) works by mere accumulation** – that is, everything you've ever experienced and learned is stored and stays there. Instead, **what goes down over time is retrieval strength (RS)**. As you stop using or retrieving a piece of information, RS goes down, but SS remains constant. The combination of SS and RS as indices of memory strength open up a space of combinations: | | High SS | Low SS | | ---- | ---- | ---- | | **High RS** | Well-learned, readily available | New information, readily available | | **Low RS** | Well-learned, not available | New information, not available The theory makes some interesting claims about the **effect of additional learning** given different combinations of SS and RS: - If something is well-learned but hard to retrieve (high SS, low RS), additional learning will result in a larger increase in RS compared to information with low SS. Forgetting (declining RS) creates opportunities for additional learning (increased SS). An example would be relearning vocabulary of a foreign language that you studied as a teenager. - If something is readily available (high RS), additional learning will result in smaller increases in SS compared to information with low RS. If you review the same concept over and over again in a single study session, each additional review will have very little impact on long-term learning. Memory that works in the way described above is **adaptive** in that it manages the **trade-off between storage size and access speed and reliability**. It uses RS as a mechanism to keep around information that's likely to be used. Most of the time, the information that has high RS is the information that we most need right now. This ensures that future requests for that information can be served faster and more reliably (that is, failures of information retrieval from storage are minimized). Finally, some additional related thoughts that I wanted to capture: - This relates to the [[There's a difference between long-term learning and short-term performance|distinction between learning and performance]]: RS is a proxy (or index) for current performance, whereas SS is a proxy for long-term learning. However, it seems that we can only directly **observe RS but not SS**. What we see during is your current performance, but not the underlying long-term learning, which is hidden. - This also reminds me of [[David Eagleman]]'s [[Pace layering model]]: Plasticity (or learning and memorization) works on multiple levels at different speeds. Changes at shallow layers happen fast whereas deeper layers change more slowly but also retain information for longer. In some sense, RS is a shallow layer of memory, whereas SS is a deeper layer. --- Created: [[2022-10-02]] Type: #permanent Topics: [[Learning (Index)]], [[Memory]] Related notes: - [[Desirable difficulties refer to challenges encountered during practice that lead to stronger and more enduring learning]] - [[There's a difference between long-term learning and short-term performance]] - [[Memory is the capacity to encode, store, and retrieve information]] - [[Learning Versus Performance – An Integrative Review]]