Ten Fun Facts About Human Memory

Each week I set out to research and document ten “fun facts” on a topic loosely based on the two books I’ve reviewed that week.  “Loosely” being the operative word. 

This week I reviewed Chinese Cooking for Diamond Thieves, by Dave Lowry, and Jory Fleming’s How to Be Human: An Autistic Man’s Guide to Life.

In Chinese Cooking, our hero Tucker seems to have an important list – a set of rules he remembers and uses to guide him through life. Lists like this are a common memory device. As the story goes on though, you realize that Tucker’s purported Life Rules are usually made up on the fly and aren’t really the memory device that he would have you believe. 

Jory Fleming takes us through an explanation of how his mind works in How to Be Human. For Jory, language is not an anchor on which to hang memories. He describes his mind as being visually organized. He stores memories in “beads”, and to recall something his mind must sort through all the beads to find the relevant one.   

Like Tucker and Jory, as we move through life each day our minds are sorting through all the input from our senses and creating memories. Some are fleeting. Some stay with us for a long time until one day we rack our brains and find we can no longer remember them. Some stay with us for life.

Our brains are funny things. Scientists have mapped areas of the brain where specific activities occur, but they also know that these areas are not always in the same place for everyone. Who’s to say that my brain processes memories the way your brain does? What we can say is that for humans, memories are an important building block for our lives. Indeed, without memories, where would we be?  

Here then, the subject for this week’s Fun Fact Friday – Ten Fun Facts About Human Memory:

Ten Fun Facts About Human Memory

1. How Many GB? – What is the storage capacity of the human brain? It’s very large, for sure, though we don’t have an exact number, as estimates vary. For example, in a 2010 article in Scientific American psychology professor Paul Reber estimated that it could be as high as 2.5 petabytes (1 petabyte = 1 million gigabytes, or GB). Professor Reber helpfully explained that this capacity is the equivalent of storing 300 years worth of episodes of The Simpsons, as seen 24 hours a day seven days a week. But this estimate of brain capacity is different than that supported by research at the Salk Institute in 2016. Their study of neurons in the hippocampus yielded an estimate of 1 petabyte, which they proclaimed was 10 times more than previous conservative estimates. At the time of the Salk study, 1 petabyte was about the size of the entire internet.

2. I Remember Everything! – Many of us picture our memories as being like a video or film of our life, but in fact, our brains do not permanently keep all the visual and sensory input they receive. A 2018 study at Columbia University demonstrates that our brains filter our experiences over time to preserve important details while letting the rest fall by the wayside.   

3. Stages of Memory Creation – To help us understand how memories form, Lesley University takes us through three stages – 1) Sensory Register – where all the information from our senses flows into our brains, 2) Short-Term Memory – made up of things you only need for a short time, as well as things the brain is working through for use later, and 3) Long-Term Memory, the “permanent” storage of memories held onto for varying lengths of time – a day, a week, a lifetime. 

4. It’s Like Riding a Bike – The type of long-term memory that seems automatic – like the memory of how to drive a car or ride a bike – is known as implicit memory. Implicit memories are unconscious, revolve around motor tasks, and are generally procedural – like buttoning a shirt or washing the dishes.

5. Storage and Retrieval – Once our brain has stored something it needs a way to retrieve it. Psychologists refer to memory retrieval methods as “encoding”. There are four generally recognized methods of encoding memories for retrieval – 1) acoustically (you hear my name and remember me), 2) semantically (you met me in a restaurant, so returning to that restaurant reminds you of me), 3) visually (I was wearing a plaid jacket at the restaurant and when you see that pattern of plaid it reminds you of me) or 4) elaborative (you know other things that you use to place a memory into context – for example, you know my parents and older brother, so you place me in the context of my family, and when you meet them later you are reminded of me).

6. He Has a Photographic Memory – A popularly held belief is that some people have a “photographic memory”, meaning that they remember everything that ever happened to them with photographic detail. For a long time psychologists thought stories of photographic memories were popular myth, but there are people who have staggering memory abilities that approach the mythical photographic type. The 2016 documentary from Real Stories, The Boy Who Can’t Forget explores a handful of such cases.

7. Sorry, I Forgot- Far from having photographic memories, most people exhibit a high degree of forgetting. This is a particular problem for employee training programs, and helps explain why many companies repeat important training on an annual basis. Learning Solutions Magazine has an interesting article on the “forgetting curve” and it’s impact on leadership training.

8. It’s on the Tip of My Tongue! – Some psychologists argue that we never really forget. The memories are still there, but our mind loses the ability to retrieve them. Sometimes your brain has the memory, but it wasn’t properly encoded, as when I give you my phone number but you don’t repeat it or link it in your head with contacting me. Other times your brain may have both the memory and the encoding, but the retrieval process itself is interfered with through stress, fatigue, anxiety or depression. 

9. Disorder – There are a number of conditions that are classified as memory disorders. Alzheimer’s is probably the most well known, and is a disorder that impacts mostly older adults. A progressive disease, Alzheimer’s not only leads to memory loss but also confusion, restlessness, inability to follow directions and more. Alzheimer’s is estimated to effect 3% of people aged 65-74, 17% aged 75-84, and 32% of those 85 and above.

10. Keep Those Memories Alive – If you are “of a certain age” as I am, and sometimes can’t find your car keys or can’t remember the name of the co-worker you’ve known for 20 years, take heart, it happens to all of us. Luckily, the Mayo Clinic has some tips to improve your memory.

So there you have it. Ten fun facts about Human Memory. Do you have a photographic memory, or are you Mister Forgetful? Do memories light the corners of your mind (you’re humming that tune to yourself now aren’t you)? Leave a comment below.