Every cognitive bias exists for a reason—primarily to save our brains time or energy.

I’ve spent many years referencing Wikipedia’s list of cognitive biases whenever I have a hunch that a certain type of thinking is an official bias but I can’t recall the name or details. But despite trying to absorb the information of this page many times over the years, very little of it seems to stick.

I decided to try to more deeply absorb and understand this list by coming up with a simpler, clearer organizing structure. If you look at these biases according to the problem they’re trying to solve, it becomes a lot easier to understand why they exist, how they’re useful, and the trade-offs (and resulting mental errors) that they introduce.

Four problems that biases help us address: Information overload, lack of meaning, the need to act fast, and how to know what needs to be remembered for later.

Problem 1: Too much information

There is just too much information in the world; we have no choice but to filter almost all of it out. Our brain uses a few simple tricks to pick out the bits of information that are most likely going to be useful in some way.

Problem 2: Not enough meaning

The world is very confusing, and we end up only seeing a tiny sliver of it—but we need to make some sense of it in order to survive. Once the reduced stream of information comes in, we connect the dots, fill in the gaps with stuff we already think we know, and update our mental models of the world.

Problem 3: The need to act fast

We’re constrained by time and information, and yet we can’t let that paralyze us. Without the ability to act fast in the face of uncertainty, we surely would have perished as a species long ago. With every piece of new information, we need to do our best to assess our ability to affect the situation, apply it to decisions, simulate the future to predict what might happen next, and otherwise act on our new insight.

Problem 4: What should we remember?

There’s too much information in the universe. We can only afford to keep around the bits that are most likely to prove useful in the future. We need to make constant bets and trade-offs around what we try to remember and what we forget. For example, we prefer generalizations over specifics because they take up less space. When there are lots of irreducible details, we pick out a few standout items to save, and discard the rest. What we save here is what is most likely to inform our filters related to information overload (problem #1), as well as inform what comes to mind during the processes mentioned in problem #2 around filling in incomplete information. It’s all self-reinforcing.

Great, how am I supposed to remember all of this?

You don’t have to. But you can start by remembering these four giant problems our brains have evolved to deal with over the last few million years (and maybe bookmark this page if you want to occasionally reference it for the exact bias you’re looking for):

Information overload sucks, so we aggressively filter. Lack of meaning is confusing, so we fill in the gaps. We need to act fast lest we lose our chance, so we jump to conclusions. This isn’t getting easier, so we try to remember the important bits.

In order to avoid drowning in information overload, our brains need to skim and filter insane amounts of information and quickly, almost effortlessly, decide which few things in that firehose are actually important, and call those out.

In order to construct meaning out of the bits and pieces of information that come to our attention, we need to fill in the gaps, and map it all to our existing mental models. In the meantime, we also need to make sure that it all stays relatively stable and as accurate as possible.

In order to act fast, our brains need to make split-second decisions that could impact our chances for survival, security, or success, and we need to feel confident that we can make things happen.

And in order to keep doing all of this as efficiently as possible, our brains need to remember the most important and useful bits of new information and inform the other systems so they can adapt and improve over time, but make sure to remember no more than that.

Sounds pretty useful! So what’s the downside?

In addition to the four problems, it would be useful to remember these four truths about how our solutions to these problems have problems of their own:

We don’t see everything. Some of the information we filter out is actually useful and important. Our search for meaning can conjure illusions. We sometimes imagine details that were filled in by our assumptions, and construct meaning and stories that aren’t really there. Quick decisions can be seriously flawed. Some of the quick reactions and decisions we jump to are unfair, self-serving, and counter-productive. Our memory reinforces errors. Some of the stuff we remember for later just makes all of the above systems more biased, and more damaging to our thought processes.

By keeping these four problems and their four consequences in mind, the availability heuristic (and, specifically, the Baader-Meinhof phenomenon) will ensure that we notice our own biases more often. If you visit this page to refresh your memory every once in a while, the spacing effect will help underline some of these thought patterns so that your bias blind spot and naïve realism is kept in check.

Nothing we do can make the four problems go away (until we have a way to expand our minds’ computational power and memory storage to match that of the universe), but if we accept that we are permanently biased—and that there’s room for improvement—confirmation bias will continue to help us find evidence that supports this, which will ultimately lead us to better understand ourselves.

John Manoogian III asked if it would be okay to do a “diagrammatic poster remix” of it, to which I of course said YES to. Here’s what he came up with:

John Manoogian III John Manoogian III, Provided by author

If you feel so inclined, you can buy a poster-version of the above image here.

I’ll leave you with the first part of this little poem by Emily Dickinson:

The Brain—is wider—than the Sky

For—put them side by side—

The one the other will contain

With ease—and You—beside—

This post originally appeared at Better Humans.