Preface: this is my geek-out blog post. I just think human memory is such an interesting topic, and there’s so many things that we still don’t know. 

This post includes just a few (out of many, many possible) tidbits of random information about human memory, along with some tips to improve your own. 

 

“The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information”

We simply cannot talk about memory without referring to this groundbreaking paper by George Miller. There’s more nuance to it, but the main takeaway is that humans can effectively process no more than 7 ∓2 “chunks” of information at a given time. This “magical number” applies to both short-term memory and other processes like distinguishing sound tones. 

Miller emphasizes that because of this limitation, an important aspect of human cognition is “recoding”, or reorganizing information into fewer chunks with more information per chunk. By recording, we can process more data, effectively overcoming the 7 item limit. For example, in trying to remember a friend’s story, we don’t memorize it word for word – rather, we organize the story into more general pieces, thus allowing us to remember more. 

 

Lack of Memory Reliability

If you’re a true-crime fanatic like me, you’ve probably also heard about how human memory is notoriously unreliable. 

There’s quite a bit of scientific evidence to back this up! The most well-known is probably the 1974 Loftus and Palmer experiment, in which researchers showed people car crash videos, then used different forms of questions to ask about the cars’ speeds. They found that the estimated speed was affected by the verb used –  participants asked how fast the vehicles were moving when they “smashed together” thought the cars were going fastest (40.8 mph). This was compared to words like “hit” (34 mph) and “contacted” (31.8 mph). Furthermore, those asked the speed when cars “smashed together” were more likely to report seeing broken glass.

A major implication of such studies is in the legal system, since eyewitness testimony can be easily biased – employing different questioning techniques after a crime is committed can cause witnesses to incorrectly recall or even create false memories. These findings raise some serious questions about the reliability of memory, especially in the courts. 

 

The Doorway Effect

Have you ever walked through a doorway and completely forgot your train of thought, or your reason for entering that room in the first place? Turns out, there’s actually a scientific reason that’s not (necessarily) dementia – memory compartmentalization. 

In a recent experiment, researchers found that when performing simple tasks, people were 2-3 times more likely to forget their purpose after walking through a doorway. 

Essentially, this is because walking through a door serves as an “event boundary”, which is meant to compartmentalize and organize your memory. Event boundaries can be incredibly beneficial in allowing us to create chronological memories and associate memories with times and locations. However, this aspect of our cognitive function can also create annoying memory lapses when your brain “shifts” while you cross these boundaries.

 

Memory + Mental Health

There’s quite a bit of nuance regarding the connection between memory and mental health; here, I’ll talk specifically about the connection between depression and memory loss, which is pretty well documented. Depression has been linked to reduced declarative memory (facts and events) and autobiographical memory (life experiences). A recent 2014 meta-analysis also found depression clearly associated with decreased cognitive performance, especially attention and executive function. 

There’s some biological reasons for this – depression can change your brain structure and chemistry, like neurotransmitter amounts and the respective sizes of various brain regions. However, it’s hard to determine causation (which happens first, memory loss or depression?), and there’s all sorts of confounding variables. For example, some studies have linked certain antidepressants, like SSRIs and tricyclic antidepressants, to memory loss. 

As of now, we can’t jump to conclusions, but this is nevertheless an interesting relationship that could be studied further. 

 

The Forgetting Curve

The forgetting curve, pioneered by German psychologist Hermann Ebbinghaus, is such a fascinating aspect of human memory. 

First of all, I think the way he created this curve was super interesting. Ebbinghaus made 2,300 random sounds (mek, rur, etc) and memorized them. Using different frequencies and durations of practice sessions and recording his practice over many years, he generated the forgetting curve.

Basically, the graph shows that we tend to forget very quickly after learning new information, and that decline slowly levels out over time. We forget more than half of the new material within the first hour! 

The main functional takeaway from the Ebbinghaus curve is that our memory decays pretty quickly unless we practice at spaced intervals. That said, this transitions into tips for memory improvement. 

 

Tips for improvement: 

1. Spaced repetition
   • Continuing the discussion of the Ebbinghaus curve, one of the best ways to prevent gradual memory decay is to practice spaced repetition. This essentially “refreshes” your memory over increasingly distanced intervals of time, allowing you to improve retention and recall. I’ve found this to be super helpful in memorizing information, like random biology terms and tidbits of knowledge! I personally love using Anki; it’s an app that’s kind of like Quizlet, but with spaced repetition programmed in. 
2. Deep work + focus (no multitasking)
   • This pains my heart a bit to write, since I’m the biggest multitasker out there – but unfortunately, multitasking is pretty terrible for memory. Instead, it’s best to set aside large chunks of time for deep focus, and group together similar tasks (for example, group all your math work together for one study session). By devoting your full attention to a task or group of similar tasks, you can seriously improve your memory and information retention. Of course, deep work also means reducing distractions! No scrolling through TikTok every 5 minutes of studying. 
3. Funky fonts
   • This one’s not as scientific, but I was reading some interesting articles on the topic and thought I’d include it. Everyone’s probably heard that taking notes by hand is best for memory recall, but since that makes my hand hurt, I often revert to typing. There’s some evidence that certain fonts may be beneficial for different purposes. 
   • For example, researchers at the University of Nebraska found that easy-to-read fonts like Times New Roman (my favorite font!) improved reading comprehension. Moreover, researchers at Princeton and Indiana University found that hard-to-read fonts (like Comic Sans Italicized) helped improve memory recall – essentially, since you have to spend more time and effort reading these fonts, you retain the content a bit more. 
   • Obviously, this is probably subjective and differs person-to-person. However, I’ve been experimenting with different fonts recently and, if nothing else, it’s pretty fun! I think it’s at least worth a try. 
4. Sleep
   • No explanation required – please get more sleep everyone.