The Revealing Truth about Our Memory Banks

What you withdraw may differ from what you deposited

Have you ever had your memory of a past event differ from that of someone with you at the time it occurred? Perhaps not so much the substance, but the details.

“Do you remember the ghastly dress so-and-so wore at the wedding.” Whaat? I don’t even remember her being there! Maybe I’m mistaken, so I’ll keep mum.

I’m more at ease having discovered our brains are not as dependable as our computers when we process and save a memory. We don’t consciously determine in which program, file type and folder to keep it.

Brain undertakes the job for us; encodes little bundles of neurons in our cortex and hippocampus and deposits the memory where we can recover it later from long-term memory in Brain’s banks such as our amygdala and basal ganglia.

Each recall is then re-encoded by a similar, yet not identical, set of neurons, thus being susceptible to change, misinformation and interference.

If Brain misses the initial details about an event, it fills in the gaps that make sense.

But it never reaches that destination if we don’t pay attention; we may well filter and reject the input in the first ¼ to 10 seconds, depending on the sensory source, and it’s gone forever.

Brain has a memory storage capacity of 2.5 Petabytes — that’s 1-million Gigabytes! More than enough for a lifetime. But we need to actively engage in using our full potential to keep Brain healthy and growing.

Anecdotes on Memory

If I write a very long sentence to tell you all about how we store memories, where they go, why they sometimes disappear never to return, how a name your were trying to remember returns six months after you gave up searching for it, or those moments when you walk into a room to fetch or do something and forget why the heck you went there and convince yourself your losing it, you forget how this sentence began.

Right? Gotcha!

It’s too much to absorb in one shot. Brain needs to catch its breath to digest in smaller bites.

It’s a key point to remember in communicating with each other — whether oral or written.

Or what if I told you that a research study in the UK has shown that 40% of the 6,641 respondents who were asked to recall with 100% accuracy their first memory and at what age, recalled a false one?

“Fake news!” you say.

Fact! This study took place in 2018 and was published in the journal Psychological Science.

Analysing the ages at which respondents recalled their first memory, the suggestion is that the mean age at which encoding, or memory formation, starts is 3.2 years.

“For this person, this type of memory could have resulted from someone saying something like ‘mother had a large green pram’. The person then imagines what it would have looked like. Over time these fragments then become a memory and often the person will start to add things in such as a string of toys along the top.”

“The thing is, the people remembering these memories do not realize they are fictional. When they are told, they often don’t believe it.”

Martin Conway, director of the Center for Memory and Law at City, University of London.

What is human memory?

We think of it as a homogenous mass sitting in our heads, ready to appear when we key in our PIN code (Particular Information Needed).

It ain’t necessarily so!

“A memory is only as real as the last time you remembered it. The more you remember something, the less accurate the memory becomes. Memory is a ceaseless process, not a repository of inert information. It shows us that every time we remember anything, the neuronal structure of the memory is delicately transformed, or reconsolidated. And that is why it’s so easy to convince naive subjects that they met Bugs Bunny at Disneyland.” — Jonah Lehrer in scienceblogs.com

In 1968 Richard Atkinson and Richard Shiffrin developed the Three Stage Model, often referred to as the Atkinson-Shiffrin model in which the sequence for processing memory is sensory, short-term and long term.

(Do I have to remember all this stuff?)

(Pay attention, then you won’t forget.)

Stage 1 — Sensory Memory

Our senses are the port of entry for all memory, stimulated by our external environment.

Brain is the customs officer, only allowing entry to information it finds useful, then forwards it to short-term memory for further inspection. Brain discards surplus goods.

Iconic — triggered by a brief visual image and lasts ¼ to ½ a second. We know this from the experiments conducted in 1960 by psychologist George Sperling.

Echoic — the brief auditory memory of a sound and can last up to 10 seconds

Haptic — tactile — a brief memory of the touch and feel of an object — lasts 2 seconds.

Gustatory — tasting something lasts less than a second

Olfactory — our sense of smell is quite the champion as we can detect and retain a wider variety of stimuli than our other senses.

(It helps that our olfactory organs live only 2–3 synapses away from our hippocampus, which processes short-term memory, and amygdala, which stores long-term memory and the associated emotions.)

Stage 2 — Short-Term Memory

Not the same as working memory, short-term memory temporarily stores information and new info entering replaces it. Working memory temporarily stores, organises and manipulates information.

We store data received from our senses in the hippocampus for only 20–30 seconds so it’s important to make the most of the time available! Without the hippocampus we cannot transfer to Long-Term Memory.

(I’ve provided a video link at the end — a true story of what happened when a neuroscientist removed a hippocampus from a patient. If you can spare 8 minutes, it’s worth watching.)

Let’s say you want to remember a phone number but don’t have pen and paper handy. (Yes, you can add the contact in your phone but this is a useful exercise to improve your memory skills and, as I love to repeat — grow your Brain!)

Note the pattern of the numbers. Here in South Africa it’s 3–3–4. If I repeat the numbers in my head in 3–3–4 time, then reinforce by repeating them out loud, it’s more likely I’ll remember the phone number.

I’m not only using echoic (auditory) memory, but adding the secret sauce of chunking. (More on that later!)

I confess if the person who gives me their number doesn’t follow my pattern, Brain crashes; I have to ask them to repeat it and end up writing it down to see the pattern. Iconic memory comes into play.

Do you recall your early days at school reciting your times tables aloud with your classmates? We learned by repetition — no calculator to help us out!

George Miller (1920–2012), an American psychologist and one of the founders of cognitive psychology and cognitive neuroscience, produced a famous paper in 1956 “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information”.

He proposed that we can only process five to seven pieces of data at any one time. To this day, no research has refuted this.

Stage 3 — Long-Term Memory

This is our final destination.

However, Stage 3 has so many branches that, in deference to your time, I will save this for another story.

In the meantime, so you don’t feel I’ve left you hanging, here are exercises to improve your working memory using this technique.

Chunking

“Our natural tendency to see patterns and make connections is not just important for memory but is also the source of creativity.” Daniel Bor, Neuroscientist

Chunking involves taking single pieces of information and grouping them into larger units. This improves our power of retention and recall. (Don’t forget we can only remember an average of 5 items at one time!)

I already gave you the example of telephone numbers.

The idea is to look for a common connection or association in the list of words.

Let’s use a grocery list.

• Group your items into veggies, fruit, dairy, grains and meat (if applicable).
• Use an acronym (mnemomics) such as coffee, rice, eggs, apples and milk — CREAM. Recall the coffee and the rest flows with ease. (That won’t work if these items aren’t on your list!)
• You can group items starting with the same letter together.

Memory is a Never-Ending Story

That’s why I’ll be back with more.

In the meantime, referring back to part of my very long sentence, I felt it only fair to tell you how you forget why you walked into a room.

It’s called the doorway effect. Our spatial memory creates an event boundary, so the act of walking into a different room, clears Brain for a new episode. Retracing your steps triggers the memory of why, and because you are now paying attention, you won’t forget.

It works for me every time!

I promised I’d be back with more — here’s the rest of the story.