Slow-Reading is The New Deep Learning
By: David Handel
Tags: Education, Learning, Psychology, Students, Reading

How We Learn New Things

What follows is an outline of the most widely accepted scientific views of learning and memory from a cognitive psychology perspective. Please be aware that for every proposed and even heavily supported model, there are always contrary views in the scientific community. Other models for understanding how memory works are continuously being proposed. This section is for the curious who want to take a look under-the-hood and understand how we learn.

I’ve written before about how memory and learning work where I took a mostly neuroscience perspective, but here we’re going to look at memory and learning from a cognitive psychology point of view.

As we encounter experiences in the world, we store information initially in Sensory Memory. Sensory memory receives the sum total of all sensory input, and it’s an overwhelming firehose of data. Imagine for a minute walking into a stadium and in a split second seeing a thousand faces come into focus, and many more thousands of blurry faces in the distance. At the same time, there is a massive amount of non-visual sensory input. There are all kinds of smells. You are also experiencing other sensory inputs in the same instant such as your sense of balance, touch, proprioception, vibration, and temperature. How can you store this continuous massive data input for the rest of your life? Would you even want to? Sensory memory input is overwhelming and fortunately, it has a very short half-life. You can only store less than a second of it at a time before it vanishes. It’s probably best that 99.99% of our sensory memory evaporates in a split second. We don’t need a complete high-resolution experiential recording of our lives in order to survive and enjoy a wonderful life.

A small percentage of sensory memory does survive and is passed to short-term memory. Short-term memory is also fleeting, lasting somewhere on the order of 10 seconds up to 30 seconds. In certain circumstances, it may last up to a minute. Short-term memory is extremely limited in capacity. The canonical research of this capacity limit culminated in the classical paper “The Magical Number Seven, Plus or Minus Two…” by Harvard Professor George Miller. He proposed that we can only remember about seven things, such as the digits of a phone number, for only a few fleeting seconds. This limit is a human experience to which we can all relate.

If a new memory is important enough to remember beyond a few seconds, it may get stored in your long-term memory, and perhaps you will remember it for a lifetime. But how does it get there? (More about this later.)

What I’ve just described is the Atkinson-Shiffrin memory model or Multi-Store Model of memory. But today, cognitive psychology has a much deeper understanding of how memory works.

The Multi-Store Model of Memory

Let’s discuss for a few minutes an important enhancement to the Multi-Store Model. The Working Memory Model (WMM), initially proposed by Baddely and Hitch in 1974. It has been enhanced over the subsequent decades and even today it is well-accepted and has a lot of solid research to support it. The WMM redefines the short-term memory portion of the Multi-Store Model and breaks it into a series of components.

Working memory is one of the most profound attributes of higher cognitive functioning. It is critical for achieving goals. Working memory is short-term storage of information, which is relevant to what we are currently doing and what we’ll do next. We employ our working memory in conjunction with other higher cognitive functions such as cognitive flexibility (the ability to shift between different tasks and concepts) to help us decide on the best approach to complete tasks. Specifically, we use working memory in conjunction with other higher cognitive functions as tools. These tools enable us to integrate our current external experiences and revive long-term memories and knowledge. We take that information and use it to interpret, analyze, manipulate, and make judgments to shape our behavior.

The Working Memory Model has enhanced our understanding of what previously called Short-Term Memory. Working Memory is where we focus our attention utilizing The Central Executive. The Phonological Loop allows us to briefly store and replay incoming auditory information. The Visuospatial Sketchpad permits us to briefly store and replay incoming visual information. The Episodic Buffer is where we manipulate ideas, new inputs, and memories. It’s the “RAM to our long-term ROM” and has been posited to be the connector between working memory and long-term memory.

The WMM has refined our understanding of short-term memory and how memories get stored in long-term memory. The original WMM described three components: The Central Executive, and two so-called “slave systems”: The Visuospatial Sketchpad and The Phonological Loop. Since 1974 the WMM has been expanded and refined. Here is an overview and summary of our current understanding of working memory.

The central executive

The central executive is a multi-faceted system that “oversees” control of working memory. It enables us to focus our attention on the current “thing” of interest while suppressing other irrelevant “things.”

These “things” could be something in the external world or they could be an internal entity such as a memory or concept. It also enables our capability to coordinate performance between several tasks, because in our modern daily lives we are very rarely only doing one thing. We have to be capable of applying multiple memories or learned concepts simultaneously. Finally, it enables us to retrieve long-term memories, so that we can apply and work with these retrieved memories to achieve our current goals.

The visuospatial sketchpad

Commonly referred to as “the mind’s eye”, the visuospatial sketchpad is the first of the “slave systems.”

The sketchpad is where you mentally visualize a current experience or a visual memory. For example, if I ask you to describe the experience of walking through your house, you will picture it in your “mind’s eye” as you describe it. This sketchpad is comprised of two components. There is a visual cache that stores but does not process optical information.

Additionally, there is the inner scribe that rehearses and replays visual, spatial, and motion data. It passes it along to the central executive. We take for granted that we have this magical ability to be able to visualize our optical memories with “the mind’s eye”, but some people, either on an acquired basis such as brain trauma or on a congenital basis, suffer from aphantasia and can’t visualize a departed loved one or a sunrise.

The phonological loop

The phonological loop is also comprised of two parts: a phonological store of auditory memory traces that rapidly decays in about two seconds and an articulatory process that we utilize to prolong the life of auditory traces in the store.

The articulatory process is used for “rehearsal”, consisting of an “internal dialog” between our “inner voice” and our “inner ear.”

Think of how you silently repeat a phone number over and over until you can find a pen and write it down. This limit of up to 2 seconds of “tape” in the store is probably the basis of the 7 +/- 2 rule.

The independent operation of the slave systems

It’s interesting that the two slave systems operate almost as if they exist on separate cores on a multi-microprocessor CPU. They each can handle only one task at a time and cannot multitask. But because they are separate systems located in anatomically distinct regions of the brain, they can function in parallel on their own tasks.

This is why, for example, we may struggle to remember a phone number told to us in a noisy cafe: the phonological loop is already engaged due to the background sounds. But we can easily recall the voice and face of a loved one at the same time since these tasks separately utilize the two slave systems. Because these systems reside in different anatomic regions, we can also prove their separateness by studying patients with brain lesions which only affect one of the slave systems. The study of patients with brain lesions is widely used in cognitive psychology to localize where functionality resides.

The episodic buffer

A fourth component was added to the WMM in 2000. The Episodic Buffer has not yet received the same degree of validation as the first three components but does appear to be generally sound.

The buffer has a limited capacity and serves as a mechanism for storing a coherent narrative that integrates the inputs from the phonological loop, visuospatial sketchpad, and perhaps other sources. It adds chronological timestamps of sorts to create an almost movie-like record.

We consciously access the episodic buffer so we can use its content to assist the completion of the current task. The episodic buffer may also underlie how memories are exchanged between short and long-term stores.

The hippocampus

The hippocampus—a part of the brain in the temporal lobe—is essential for the conversion of short-term memory (stored in the episodic buffer) into long-term memory. If your hippocampi were removed like Henry Molaison’s, you would be incapable of creating new long-term memories.

Only a small portion of our working memory makes the trip into long-term storage. This occurs through a process called consolidation. Consolidation seems to happen best when we are not as actively engaged with the material, such as when we’re sleeping, relaxing, or taking a walk. Subconsciously, during these times, various processes within the hippocampi replay and ‘encode’ the contents of the episodic buffer to the neocortex. This repetition creates new synaptic connections and strengthens existing connections to create small groups of neurons known as engrams​, which together as a unit store the memory. Furthermore, these engrams are also encoded in the prefrontal areas, the region of the brain which enables higher executive functioning, highlighting how important our memories are to shaping our behavior in complex tasks.