Cognitive biases describe the built-in thinking errors that humans make when processing information.  There are 175 listed on the “List of Cognitive Biases” page in Wikipedia.  These range from the popular Confirmation Bias to the Forer Effect and everything in between.  There are many, and they are difficult to remember mainly due to their vague categorizations.

Tired with the tangled mess, Buster Benson organized the biases neatly over on this blog, Better Humans.  From there, John Manoogian remixed the newly categorized information into a diagrammatic masterpiece of a poster.

“Since learning about confirmation bias, I keep seeing it everywhere!”

A bit of pre-amble before diving into the codex, summarized from Benson’s article.

In order to avoid drowning in information overload, our brains need to skim and filter huge amounts of information and quickly, almost effortlessly, decide which few things in that deluge of information are actually important and “call those out”.  But that means we don’t see everything. Some of the information we end up filtering out is actually useful and important.

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

In order to act fast, our brains need to make split-second decisions that could impact our chances for survival, security, or success.  The downside, on the other hand, is that quick decisions can be seriously flawed. Some of the quick reactions and decisions we jump to are unfair, self-serving, and counter-productive.

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.  The trade-off?  Our own (fallible) memory reinforces errors, so some of the things we remember for the future sets us up for bias, and ends up more damaging to our thought processes.

Given all that, we are ready to review the codex.  Click the image to see a much larger and legible version and so you can see it in all its glory.

The Cognitive Biases Codex - a cheatsheet


Cognitive biases are just tools, useful in the right contexts, harmful in others. They’re the only tools we’ve got, and they’re even pretty good at what they’re meant to do. We might as well get familiar with them and even appreciate that we at least have some ability to process the universe with our mysterious brains.

Buster Benson

Cognitive Bias Codex:


  • Kinders

    This is great – but Occam’s Razor isn’t a cognitive bias. I can see how it got put in the section it did (“we favor simple-looking options and complete information over complex, ambiguous options” – this is essentially a summary of Occam’s Razor) – but it’s not a fallacy or a cognitive bias, it’s a sound principle. I’m not sure it belongs on the codex…

    • Villainess

      Occam’s Razor is not a sound principle when it forces people to ALWAYS rule out ideas as false simply for being too complex and ALWAYS in favor of simplicity. The evolved world is complex, and interwoven causalities are more often the correct answer that we human scientists, investigators and philosophers cannot so easily study.

      It does have a cool and memorable name that makes it easy for simple folk (not like you?) to argue for. Just remember that at heart, the razor is a mere suggestion/cheat for quickly arriving at a “more likely” solution. The difference between 50.0000001% and 99.9999999% likelihood is a world of difference, yet they both are still considered “more likely”. And, of course, LIKELIHOOD IS NEVER A CERTAINTY! So we need to remember to keep quick and useful solutions arrived at with this gambling tool in a red mental lock box with all the other questionable thoughts we cling to as truth. The challenge is in NOT depending on them as truth once they are in our thoughts.