Everybody hates that feeling when you spend three weeks reading a book, and a month later somebody asks you about it and you can't remember a thing you read. It makes you wonder why you wasted a couple of hours on the words that didn't stick.
There are some effective ways to learn. And when I say "to learn effectively", what I mean is to not just build up knowledge, but to be able to apply (应用) that knowledge effectively at some point in the future. By this definition, most of the courses people spend money on is not learning. Something is not truly learned until it changes you in some way.
1 Memory is based on relevance (相关性)
One of my favorite online book clubs is Mentor Box. What's cool about the club is not only do they send you books to read, but they send you study materials related to them. The study materials, instead of being like school, where it asks you to repeat information in the book to help memorize it, are designed to help you apply the lessons to various areas of your life.
That's because memory works based on relevance. We only remember what our brain has considered important to our own lives. If you don't find a way to make it relevant to you and your well-being in some way, your brain will conveniently forget it.
You can do this on your own. When you come across something interesting in a book, write down its application or relevance to something in your life—how you can use the idea, how it explains something in your past, how it can help with your problems, etc.
2 Reading does not have to be linear
People believe they have to read everything, line by line, one after another. This is not only not true, but it's often a waste of time and energy.
When you buy a book, you're not buying the words, you're buying the useful ideas. The point of a book is to gather the information that is relevant and important to you, not to finish it or to understand every word. What matters is the principle or key idea. Once you've received that principle or idea, there's no reason to feel obligatedto sit there and read the rest.
3 Think critically and ask the right questions
Everything you read should be questioned. You should question the writer's biases (偏见), whether they're explaining information correctly, whether they're overlooking something. When reading something I agree with, I'll ask myself, "Is it possible that this could be wrong?" Everything should be taken with a grain of salt, for the simple reason that almost everything is largely uncertain. And it's the ability to manage those uncertainties effectively that will determine the depth of your knowledge and understanding, not the ability to memorize a lot of facts and numbers.
