The Science of Forgetting

I once heard someone exclaim that their forgetter was getting better. Few would argue that our ability to remember and recall information decreases with age, but we seem to have a decent grasp on the art of forgetfulness from an early age. In fact, the ability to send information to the brain’s equivalent of a computer’s trash can or recycling bin appears to be an important part of the way God has designed our mortal minds to function. Even the forgiveness of God according to various passages of Scripture gives the blessed promise that ‘their sins and iniquities I will remember no more’. Yet despite this positive perspective, a student exclaiming ‘I forget!’ has likely caused many teachers to inwardly groan. We may even be tempted to think or say things like:

• Weren’t you listening when I explained it?
• But you knew how to do it this morning!
• We just learned this yesterday!
• We’ve reviewed this so many times!

These may all seem like perfectly valid (and perhaps familiar) responses, yet they do not align well with what educational psychologists understand about how our brains go about storing information for future use. While a universally agreed-upon description of how learned facts and skills are stored in one’s long-term memory is yet to be uncovered, teachers have much to gain by applying ‘the science of forgetting’ in their classrooms. Learning is a complex process, and things do not always go according to plan.

Weren’t you listening when I explained it?

Even the most attentive listening is not enough to guarantee the formation of long-lasting memories. Without further rehearsal or practice, the working memory (or short-term memory as it is sometimes called) only has a span ranging from 15-30 seconds before the information begins to fade away. Perhaps you have experienced this effect when trying to remember a phone number long enough to either dial the number or write it down on a notepad. Without the rehearsal, the numbers quickly begin to fade away as if they were a useless series of digits. Other research shows that information can be displaced from the working memory as more information comes in. To picture this, imagine a group of students trying to squeeze onto a single bench. Once the bench is full, someone sliding onto one end is going to push someone off the other side. As a result, people are far more likely to remember the last things someone said rather than a statement from either the beginning or middle (McLeod, 2015).

To enhance student learning from listening, teachers can require students to practice what are known as active listening strategies. Writing summaries, creating mind maps or other forms of notetaking, and incorporating engaging questions (from both teachers and students) are all strategies that encourage students to remember information from a lecture-based class.

But you knew how to do it this morning!

Research on how people learn shows that there is indeed a time component involved in memory, yet being able to recall something this morning (or yesterday, last week, in November, etc.) has little influence on whether we know and are able to recall it now. Memory is significantly impacted by how deeply students have processed information when it is learned. Classroom activities that require students to think more deeply about content will make it more likely that the information will be available later (Craik & Tulving, 1975).

Activities a teacher may consider promoting deeper processing of lesson content include connecting the new learning to students’ personal experiences and prior knowledge, looking for patterns or overarching themes, and considering the implications of the lesson (i.e. Why does it matter?). Bloom’s Revised Taxonomy (Forehand, 2005) can be a guide to understanding what learning activities will be more likely to result in students creating longer-lasting memories.

We just learned this yesterday!

Consolidation is the term given to the brain’s process of recording new learning into its vast system of neural pathways. In other words, learning involves biological changes in the brain, and this process takes time (McLeod, 2023). Furthermore, there are a variety of circumstances that can either shorten or lengthen the amount of time required for this process to complete. In some instances, learning can be encoded in the brain’s long-term memory in a matter of moments, but some research has indicated that some memories may require up to two years before they are fully embedded into the brain. Therefore, ‘learning something yesterday’ or even at any point within a present school year is still a relatively brief time horizon.

It is beneficial for teachers to keep in mind that learning is rarely a ‘once and done’ process. Episodic memories (autobiographical memories of life events) and flashbulb memories (e.g. remembering what one was doing when learning about events such as the 9/11 attacks, the JFK assassination, or the bombing of Pearl Harbor) are a few examples, but these generally do not align with the learning that takes place in classrooms. To assist with the encoding of memories, teachers can use a multimodal approach to learning that invites students to engage with content in a variety of formats and contexts. Contrary to popular thought about students requiring specific types of activities to match their learning style, research shows that everyone benefits from a varied approach (Willingham et al., 2015). Spacing learning activities associated with a specific skill or fact over an extended period of time rather than doing everything all at once is another way to boost memorization.

We’ve reviewed this so many times!

To help understand this one, consider an ordinary penny. You have probably seen tens of thousands of them in your lifetime – but do you really know what they look like? Without peeking, take a piece of paper and try to draw the ‘heads’ side of this coin complete with the right person’s profile facing the correct direction along with all the necessary words and numbers in their proper positions. If you can successfully complete this task, you are to be commended because very few people can do it. In fact, most adults are unable to even recognize a correctly drawn penny when presented with a collection of slightly altered fakes. While repetition may be beneficial in some contexts, it generally leads to short-lived memories with little understanding – and may even slow down content mastery (Tulving, 1966).

Rather than repetition, teachers can incorporate a variety of activities for students to engage with material in novel ways. Each new method will result in students creating different connections in their memory, which will encourage longer retention of the learning. For example, rehearsing math flash cards has its place in the classroom, but engaging with math facts in other ways can help many students ‘learn their facts’ faster and with greater automaticity. Activities like 24 Game and the additional activities from their classroom activities list are excellent ways for students to strengthen memory and conceptual knowledge of math facts.

In conclusion, an understanding of how people remember and forget information can invigorate our teaching. While it may be tempting to express frustration when students appear to have forgotten their past learning, it can be helpful to know that there are strategies that teachers can implement to boost long-term memorization. By helping our students to conquer many of the most common obstacles to remembering lesson content, we can create a classroom that will have a lasting impact on our students’ lives.

References

Craik, F. I., & Tulving, E. (1975). Depth of processing and the retention of words in episodic memory. Journal of Experimental Psychology, 104(3), 268-294. https://doi.org/10.1037/0096-3445.104.3.268

Forehand, M. (2005). Bloom’s taxonomy: Original and revised. In M. Orey (Ed.), Emerging Perspectives on Learning, Teaching, and Technology (pp. 41-47). The Global Text Project

McLeod, S. (2023). Theories of forgetting in psychology. Simply Psychology. https://www.simplypsychology.org/forgetting.html

Tulving, E. (1966). Subjective organization and effects of repetition in multi-trial free-recall learning. Journal of Verbal Learning and Verbal Behavior, 5(2), 193-197. https://doi.org/10.1016/S0022-5371(66)80016-6 Willingham, D. T., Hughes, E. M., & Dobolyi, D. G. (2015). The scientific status of learning styles theories. Teaching of Psychology, 42(3), 266-271. https://doi.org/10.1177/0098628315589505

Photo by dianne clifford on Unsplash