When you finish work and go home, you don't even want to think about the dinner menu.
Even if you open Netflix, you don't have the energy to choose what to watch.
You just stare at your phone in a daze and realize you've fallen asleep.
I think many people can relate to this feeling of "I don't want to think about anything anymore."
Actually, this isn't just simple fatigue; it's a phenomenon that can be scientifically explained as the depletion of cognitive resources. Our brains have "resources" that can be used for thinking, judgment, concentration, and self-control, and these definitely decrease throughout the day.
If you know how they decrease, how to save them, and how to recover them, you can keep your head working even in the evening.
So this time, I've structurally organized what "cognitive resources" are based on cognitive science research, and for each component, I've experimented with:
- Situations where cognitive resources are worn down
- Techniques to save them
- Methods to recover them I'm writing this down on note as a memorandum.
It's quite long, but I've summarized it so it can be used as a reference, so I hope it helps.
There Seem to Be 4 Types of Cognitive Resources
When you hear "cognitive resources," you might imagine a single gauge decreasing like a smartphone battery. However, based on current cognitive science knowledge, cognitive resources seem to consist of four components.
① Attention
The ability to keep focus on a specific object and exclude irrelevant information. In short, attention span.
In Daniel Kahneman's famous "Attention and Effort," it was shown that attention has an upper limit on its total amount, and if you direct attention to multiple objects simultaneously, the amount that can be allocated to each decreases.
② Working Memory
The ability to manipulate information while temporarily holding it in your head. According to "The episodic buffer: a new component of working memory?," the upper limit of information chunks (called chunks) that can be held and manipulated in the head at once is about four.
That feeling of "I have to remember this, and that too" where your head feels like it's exploding and you think, "Wait, what was I supposed to do...?" That sensation is working memory overload.
③ Self-Control
The ability to suppress impulses, regulate emotions, and control behavior in line with long-term goals. In "Ego depletion: is the active self a limited resource?," self-control was considered to consume a finite resource.
In short, it means the brain uses energy to "endure" or "suppress emotions."
④ Decision-Making Function
The ability to compare and evaluate options and make judgments. Decision-making is performed by mobilizing:
① Attention: Focusing on options
② Working Memory: Comparing options in the head
③ Self-Control: Suppressing impulsive options (like wanting to go to an after-party) while making a proper choice (like going home properly)
...all of these. That's why it's the most easily exhausted.
Now, let's look at what wears down each of these four components, how to save them, and how to recover them.
① Recovering "Attention"
Why does it wear down?
It's multitasking, after all. Checking email → planning document → chat reply → planning document again... Every time you switch, a "switching cost" occurs. For example, according to research cited in a Harvard Business Review article, it takes an average of 23 minutes to refocus on an interrupted task.
A 2009 Stanford University experiment was even more shocking, finding that people who frequently do "multi-tasking" are actually less efficient at switching from one task to another. You'd think people used to multitasking would be better at task switching, but the opposite was true. This is because the human brain only appears to be processing multiple things at once; in reality, it's just switching attention at high speed.
In addition, interruptions like notifications, calls, and SNS hit your attention like body blows. Every time a notification sounds, you're forced to judge "Should I look?" or "No, focus now," and this alone depletes your attention resources.
The Multitasking Strategy I Devised
I myself had a period where I was tossed around by multitasking and my productivity didn't improve at all.
Back in my consulting days, there was a boss with insanely high productivity, and observing them made me realize something.
No matter how superhuman a person is, they weren't doing multitasking.
Specifically, I realized it's okay to process tasks in the following order:
- The 1st priority should be tasks that require requests to others. While you hold the ball, nothing progresses.
- The 2nd priority should be tasks that can be settled within 10 minutes. As uncompleted tasks pile up, concentration drops. So, it's better to reduce the uncompleted state as much as possible.
- The 3rd priority should be breaking down tasks that take more than 3 business days. For large tasks that take more than 3 business days, try moving your hands once and break them down into task sizes that can be completed within 3 business days. This makes the overall picture of the task clear and makes it easier to prevent deadline delays.
- Tasks that don't fall into 1-3 are processed in order of their deadlines.
Illustrated, it looks like this:
You can recover quite a bit just by walking for 10 minutes
According to "The Cognitive Benefits of Interacting With Nature,", it has been experimentally shown that walking in nature for about 20 minutes can recover attention.
However, it's difficult to take a 20-minute walk during the day when you're busy every day. So, in my case, I try to walk for just 10 minutes during lunch.
I work remotely a lot, and there happen to be these stairs near my house.
There are 250 steps. I go up and down these stairs and go home. This takes exactly 10 minutes.
It's only 10 minutes, but I feel my afternoon concentration is significantly recovered.
② Don't Let "Working Memory" Explode
Why does it explode?
Doing tasks with high cognitive load causes working memory to explode. As mentioned earlier, if the amount of information to be processed exceeds the working memory capacity (approx. 4 chunks), the efficiency of learning and thinking drops sharply. Situations like writing minutes while facilitating a meeting or operating a system for the first time feel like "smoke is coming out of my head, I can't do this anymore" because working memory has reached its limit.
Another troublesome issue is that uncompleted tasks continue to reside in the head. As I've written in my notes several times, the more uncompleted tasks remain in your head, the harder it is to focus on what's in front of you.
In short, it's the same as a PC becoming heavy when you have many Chrome tabs open. "I have to do that" and "I have to remember this" keep running in the brain's background, reducing the memory available for the task at hand.
I recommend the "Empty Brain Organizing Method"
What I do to lower the load on working memory is the Empty Brain Organizing Method. The method is simple: when you gain knowledge from reading a book or web article, or when an idea or question comes to mind, immediately write it down on paper.
You don't need to make it a picture, but if you did, it would look like this:
There are three scientific reasons for this:
① Cognitive Offloading
A concept shown in "Cognitive Offloading", which is reducing the brain's load by writing out memories and thoughts externally. Writing notes, putting things in a calendar, writing to a ToDo list. Just this releases the load of "having to remember" from working memory.
② The Extended Mind
In "The Extended Mind", it is argued that "information written in a notebook you always carry is functionally equivalent to memory in the brain." In other words, paper notes can be used as part of the brain. However, there are conditions:
- It must be used constantly
- It must be retrievable immediately
- You must be able to believe the written content Because of these three, the effect is completely different between someone who only takes notes occasionally and someone who takes notes as naturally as breathing. By the way, so I can take notes immediately, if I press the side button on my phone, ChatGPT starts up, so I use voice input there to take notes.
③ Writing out uncompleted tasks
What's interesting about the research in "Consider it done! Plan making can eliminate the cognitive effects of unfulfilled goals." is that even if you don't actually complete the uncompleted task, just writing down a plan for "when, where, and how" eliminated the occupation of working memory. In other words, you don't have to finish the task; just writing it down is enough. The moment you write it down, the brain judges, "You can close this tab now."
③ Create an Environment Where "Self-Control" is Minimal
Why does patience run out?
According to "Self-regulation and depletion of limited resources,":
Resisting the sweets in front of you while on a diet.
Suppressing the urge to open SNS during work.
With every such "patience," self-control resources are consumed.
This means there is an upper limit to the number of times you can endure.
Just create an environment where you don't have to endure
So, it becomes a flip-side solution, but the greatest saving technique for self-control is "creating an environment where you don't have to use self-control in the first place."
I explain this in more detail in my note, so please take a look if you'd like.
