There is fundamental difference between feeling informed and truly understanding something.

We are as informed as ever. We can more or less parrot opinions we read, cite random facts, but when tasked with explaining what something is all about, why it is the case, what its connections are with other facts and theories, and putting it in context, we fall flat on our face. 

It's dangerous when we let these illusions of competence slip into our opinions, as we so often feel strongly about a position, but if pressed, we could hardly argue for it. 

There's two main parts: short-term and long-term. Think of the long-term memory like an investment portfolio. As you gather more and more schemas, you gain intellectual compound interest over time. They all begin to connect to each other, increasing your understanding of the world exponentially over time, but for information, to get to your long-term memory in the first place, it has to go through a part of the short-term memory called working memory. Working memory has slots where we process information. It acts as a bottleneck for the infinite amount of information around us.

The problem is what we hold there can quickly vanish if we don't keep thinking about them or rehearse them in our heads. In other words, if we don't grapple with the ideas in our working memory for an extended period of time, they never get sent to the long-term memory. They just disappear.

Our current culture makes this process challenging. We're blasted with new stimuli and information rapidly. This couldn't be worse for our memories. Info jumps in to working memory only to be replaced by the next thing and the next thing. Very little of it, if any, makes it into long-term memory.

But it's not just information overload that affects our ability to remember things, multitasking is just as bad. 

Our brains are designed to focus on one thing at a time. When we multitask, all we're really doing is quickly switching from one task to another and our brain struggles to commit anything to long-term memory when we're constantly task switching, tab shifting, and notification checking. Every switch is like hitting the reset button.

It gives no time for deeper processing. This also reduce the number of working memory that goes to long term memory.

The first is to eliminate multitasking, distractions, and information streams that cause overload. We're all well aware at this point that these services exploit our psychology and it's hard to resist the addicting dopamine surge that comes from checking them.

The next one is find one source to focus on and start absorbing the info, then do some or one of next steps to keep it in our memory longer; recalling, Feynman technique, and space repetition.

After you've read or watched any material, simply look away and see what you can recall from the material you've just taken in.

Practicing recall is counterintuitive to most consumers of content. You finish a chapter and you go to the next one or you finish a video and move on to something else, but spending as little as 30 seconds after finishing a chapter or video and recalling its key points vastly improves your understanding of a topic and commitment of it to long-term memory.

The steps in Feynman Technique are:

1. Take something you wanna understand.
2. Write out an explanation as if you were teaching it to someone who didn't understand the subject. 
3. Whenever you get stuck, go back to the material and relearn. Eventually, you'll fill in the gaps in your knowledge until you can write an explanation without needing the source material.  
4. Finally, attempt to simplify your explanation, getting rid of technical terms and convoluted language. Simplify it to the point that a kid could get what you're saying. Analogies is one of the method to simplify.

Our brain is working more like a muscle than a computer; it's wrong that once a info go in our brain then it will be there forever, the brain need to be exercised. The more often you use the neurons grappling with the information you want to commit to memory, the stronger those connections will get and the stronger your memory and understanding of that information will get. 

Spaced repetition does this by firing the neurons over a long period of time. 

The best idea to remember things are do all three above; recall, Feynman technique and make it repetition; spaced them out by three days over the course of a couple weeks, it results in the highest amount of memory retention.

You don't need to be memorizing and understanding everything that comes your way. That's absurd. spend more time thinking about one important thing at a time instead of trying to absorb as much information as possible only to forget most of it. 

To recognize the limits of your knowledge and to appreciate others’ intellectual strengths is one of the best things a person can do. It's not only where learning happens but it's also where disagreements become more constructive. The trick is not to be fooled by illusions of superiority and to learn to accurately reevaluate our competence each day.