[1] Memories can be cruel. As a girl is about to raise her hand in class, the prior experience of being discouraged by a teacher emerges in her mind, the scene floating before her eyes, classmates’ voices rebounding inside of her ears, and she can feel the blush on her cheeks. People tend to try their best to put behind unpleasant memories, which, unfortunately, are often the more rememberable ones. To forget, one might think the best way is “not to remember." However, contrary to previously held beliefs, a team of neuroscientists led by Tracy Wang discovered that intentional forgetting was most successful when there was moderate activation of the material to be forgotten in relevant cerebral regions. In this essay, I will discuss how forgetting is undervalued in conventional pedagogies and explain why I believe findings from Wang's study have profound implications for helping students realise their best potential in classrooms.

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[2] Memorization has long been incorporated into pedagogies around the world. Memorising vocabulary, mathematical theorems, or physics laws often aids students in achieving high test scores, which usually serves as an important metric for measuring student performance. In some Asian countries, increased emphasis on test scores means more memorisation tasks for students, which raises concerns about equating the memorisation of knowledge with learning. Various strategies seeking to enhance memorisation have been proposed, including sleep regulation, physical exercises, and offering rewards (Ribeiro, 2014; Trudeau, 2008; Mitry, 2001).

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[3] Forgetting, on the other hand, is seldom associated with pedagogies. Many of us are frustrated with forgetting, when we fail to remember the facts for a big test or miss the deadline of an essay submission. However, many learning science theories have proposed that students are constantly affected by their learning environment, especially by negative memories from the past. Research has also shown that students benefit greatly from being able to forget unwanted memories. Bear and Malenka (1994), for instance, discovered that when acting on the same item, memorisation and forgetting are two different processes, which rely on long-term potentiation (LTP) and long-term depression (LTD) respectively; however, when directed at different items, LTD does facilitate LTP. McFarlane and Humphreys (2012) took their findings a step further and found that the removal of unwanted information from students' brain contributed to a better memorisation of more important information.

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[4] Much of our forgetting is unconscious, unintentional forgetting, which is passive and irresistible (Maxcey, 2019). This type of forgetting, as Frankland et al., (2013) suggested, is a natural process that happens in the brain to clear up space. Hippocampus, the brain region associated with memorisation, draws connections between neurons and circuits physically and chemically (Fell, 2001). Continuously exposed to incoming information, the hippocampus, even when we are sleeping, is busy coupling and decoupling neurons. However, not all information is worthy of the hippocampus' attention — unimportant information is either filtered or overlooked — which leads to forgetting.

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[5] However, as discussed earlier, there are circumstances where we want to be able to forget something at will, be it an embarrassing incident, or previous failure. Whether the intention to forget affects our ability to forget has long intrigued both psychologists and neuroscientists. One of the earliest available researches exploring intentional forgetting was conducted by Lehman and Bovasso in 1993, in which they explored intentional forgetting in children. Two mechanisms for intentional forgetting have since then been proposed: direct suppression and thought substitution. In 2005, a team led by PT Hertel discovered that the mingling of the target neuron with other signals led to successful forgetting (Hertel, 2005). This result was in line with the thought substitution hypothesis, which states that forgetting is achieved when alternative memories, rather than unwanted memories, are activated. The direct suppression hypothesis, on the other hand, states that forgetting is successful when unwanted memories are inhibited. van Schie et al. (2012) found evidence for this resorting to the Think/No-think paradigm. When we are asked to forget something, the dorsolateral prefrontal cortex in our brain sends inhibitory signals to the hippocampus and prevent memory encoding in this brain region. Both the direct suppression and thought substitution hypotheses imply that in order to forget an unwanted memory, one needs to turn away from engaging with it.

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[6] A recent study conducted by Tracy Wang and her colleagues shed new light on the mechanisms of intentional forgetting. The team recruited twenty men and women to view a set of 200 images of faces and scenes on the screen. Next to the images were commands of either “TBF (to-be-forgotten)” or “TBR (to-be-remembered)”. While participants studied the images, the experimenter used fMRI to observe the activities of their ventral temporal cortex and sensory cortex. After this visual input, the participants are asked to recall the images they just saw. The main results of this study were twofold. First, the TBF commands were associated with enhanced brain activity. Second, participants were most successful at forgetting the TBF images when there was moderate, not too high or too low, brain activity when studying the images. As concluded by Wang et al., (2019): "An increase in attentional focus on TBF items during a deliberate forgetting attempt increases their memory activation, which in turn, facilitates their forgetting." Although it is unclear what strategy participants used — thought substitution, direct suppression, or both — to forget the items, contrary to previous assumptions, moderate processing of to-be-forgotten memories improves rather than inhibits the forgetting of these memories.

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[7] These findings have profound implications for education. Educators first need to understand the impact of negative memories from the past on student performance. They also need to incorporate methods that teach students how to navigate these negative memories through their learning experience. To minimise the impacts of negative memories, educators should help students learn to properly engage with their own memories rather than suppress or avoid them. One such practice is mindfulness, an approach by which students learn to observe their own thoughts and memories without trying to judge, analyse or suppress them (Valentine, 2019). Moderate engagement with unwanted memories might, in turn, improve students' ability to forget about those memories.

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[8] Practicing engaging with memories has benefits beyond just preventing students from being affected by unwanted memories. Learning to engage with one's memories improves people's attentional abilities. Malinowski (2013), for instance, discovered that mindfulness helps refine people's ability to allocate attention to information at the onset of input processing, and improves people's capacity for attention control.

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[9] Furthermore, learning to engage with one's memories also improves people's abilities to cope with their emotions. When a student frequently recalls a stressful event, thereby starting to feel anxious or depressed, the pituitary gland - under the command from the hypothalamus - starts to stimulate the adrenal glands in his or her body, thus propelling the secretion of an excessive amount of cortisol. An excess amount of cortisol can compromise the student's immune system, rendering his or her more susceptible to diseases (Hoehn, 2010). Both the pain and possible sicknesses can give rise to a higher stress level, forcing the brain commanding the system to secrete a greater amount of cortisol. This way, the body and the brain mutually and negatively feedback to each other. With some emotional events removed from the brain, this feedback cycle will less likely be initiated - the way in which intentional forgetting benefits students in terms of their memorisation abilities and physical health. With the coordination between body and mind, the emotional state of students – during their studies – will be more stabilised and thus beneficial.

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[10] One may misunderstand the significance of forgetting as only limited to prevent every negative emotion such as awkwardness, which is an absolute understatement. With a tremendous number of people joking that they are “depressed,” the severity of depression may not be overlooked. A recent study discovered that people with depressive tendency are more likely to recall negative experiences in the past (Xie et al., 2018). With some 350 million people across the globe suffering from this illness, according to a 2018 survey, depression is undoubtedly influencing the world population immensely (Licinio et al., 2018). Negative memories, both the cause and the symptom of depression, constitute a vicious cycle so malevolent that harms the hippocampal function and can even drive people suicide (Beck, 2009). Closely related is PTSD, or post-traumatic stress disorder, which are mostly caused by the experiences of violence, rape, and war, which give rise to a frequent and morbid recall of these memories (Yehuda, 2002). In the aspect of forgetting unwanted or sometimes detrimental memories, the strategies to undermine or divert relevant brain circuits may be of use by breaking the thorny cycle. Incorporating the skill of “how to forget” in education will to a large extent prevent the aggravation of memory-related psychological syndromes like depression and PTSD, reducing the hospitality fee, suicide rate, and social turbulence. Therefore, if one takes a more in-depth view, “forgetting” becomes even more crucial to individuals and societies.

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[11]Integrating materials from psychology and neuroscience, I have demonstrated that forgetting can be an important learning strategy for students, who are under the constant influence of memories from their experience. Tracy et al., (2019) showed that forgetting is not a “laissez-faire” process — the intention to forget increases processing of the to-be-forgotten material, and contributes to its successful forgetting. Given this newly acquired insight about how forgetting works, educators shall develop strategies to help students better engage with their memories, and forget them when in need. With comprehensive and appropriate applications of the technique of intentional forgetting, we are expected to see further socio-economical benefits, as educational institutes are the reproduction of current, and hopefully future, society.