According to a paper published in the June 21, 2017 issue of the scientific journal Neuron, the brain is hard-wired to forget information. Neurobiologists Blake Richards and Paul Frankland, the authors of the study, challenge what has become the dominant theory of memory, which holds that forgetting involves the gradual loss of critical information. According to the authors, the goal of memory is not just to store information accurately but to “optimize decision-making” in environments subject to rapid change. Forgetting then becomes an evolutionary strategy that evaluates information and deletes that which doesn’t promote the survival of the species.
“From this perspective, forgetting is not necessarily a failure of memory,” explain Richards and Frankland in the study. “Rather, it may represent an investment in a more optimal mnemonic strategy.”
While many people think of a memory as a file stored somewhere in the brain, this is not actually the case. A single memory may be stored across what looks like a spiderweb of connected neurons, whose job it is to encode the information in the network and convert the experience into a memory. The key to retaining the information, though, is how often and how strongly this network is accessed.
In the 1880s, psychologist Hermann Ebbinghaus pioneered research in the field of learning and retention; one of his key observations was what he called the “forgetting curve.” It is a measure of how much we forget of the information we learn over time. He discovered that if there was no reinforcement of, or connections to, prior knowledge, the information would be quickly forgotten—about 56 percent in one hour, 66 percent after a day, and 75 percent after six days. What’s intriguing, though, is that the same neural circuitry appears to be involved in both remembering and forgetting. That means students and teachers should be able to adopt strategies to reduce memory deletions and reinforce material that needs to be remembered for later recall.
In a 2015 Neuron article, MIT neuroscientists, led by Richard Cho, explained the mechanisms for synaptic strengthening. When neurons are fired frequently, synaptic connections are strengthened; when they are rarely fired, the connections are weakened. This is referred to as “synaptic plasticity,” and it goes a long way toward explaining why some memories persist while others fade away. Repeatedly accessing a stored but fading memory—like a mathematical rule or an historical fact—rekindles the neural network that contains the memory and encodes it more deeply.
The researchers also showed that not all memories are encoded equally. A random sequence of letters, for example, is quickly forgotten, as it evokes no meaning. A word like “orange,” though, contains a deeply encoded linguistic context. We have seen the color. We know what the fruit looks like. The word may evoke sensory memory, not just from the image of an orange, but also from its smell, and perhaps even memories of how it tasted when you ate one. You remember this word by layering new memories on the foundations laid by older ones.
So how does this affect reading and education? Basically, students need to make as many neural connections as possible with the information presented, and they need to access that information repeatedly over time. The following five strategies are effective in helping retain information while in a classroom setting.
- Peer-to-peer explanations: When students have to explain what they’ve learned to peers, the required memories are reactivated and strengthened. This strategy not only increases retention but also encourages active learning.
- The spacing effect: Instead of covering a topic once and then moving on, it helps to revisit key ideas throughout the semester or school year. Research has documented that students perform better when given multiple opportunities to review learned material. These opportunities can be anything from a formal review incorporated into a class to a midterm or other cumulative exam, or a term paper building on the ideas presented in the classroom.
- Frequent practice tests: Just like reviewing material, giving frequent practice tests can boost long-term retention; it can also help protect against stress, which often impairs memory performance. Practice tests can be low stakes and ungraded, such as a quick pop quiz at the start of class, or a single high-stakes test broken down into several smaller tests given over time.
- Interleaving concepts: Don’t group similar problem types together; instead, mix them up. Solving problems involves identifying the correct strategy to use and then putting that strategy into action. When similar problems are grouped together, students don’t have to think about what strategy or strategies they need to use —they automatically apply the same solution over and over. Interleaving forces the students to think about the appropriate strategy to use in a particular instance, and this encodes learning more deeply
- Combine text with sounds or images: It’s often easier to remember information that’s been presented in multiple formats, such as a recording of a lecture or a visual aid of a concept. When the brain receives multiple inputs of the same information, it’s more likely to regard the information as important and encode it for later recall.
What strategies have you found useful for retaining information? Leave us a note in the comments section below.
 Richards, Blake A., and Frankland, Paul W. (June 21, 2017). “The Persistence and Transience of Memory” in Terada, Youki. “Why Students Forget—and What You Can Do About It.” Retrieved from https://www.edutopia.org/article/why-students-forget-and-what-you-can-do-about-it?utm_source=twitter&utm_medium=socialflow
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