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Jul 24, 2021 27 tweets 6 min read Twitter logo Read on Twitter
Cognitive biases are systemic errors in thinking that negatively impact decision-making quality and outcomes.

THREAD: 20 cognitive biases to learn (so you can think clearly and make better decisions):
Fundamental Attribution Error

Humans tend to:

(1) Attribute the actions of others to their character (and not to their situation or context).

(2) Attribute our actions to situation and context (and not to our character).

We cut ourselves a break but hold others accountable.
Bandwagon Effect

Humans are a social species - this allowed us to thrive.

But it also has a downside…

It creates a strong tendency to speak, act, or believe things simply because a lot of other people do.

Bandwagon effect is similar to "groupthink" and is very dangerous.
Egocentric Bias

The human tendency is to have a higher view of one's self than is objectively warranted.

In group activities, we tend to overestimate (in comparison to objective measure) the degree and value of our own contributions relative to others.
Naïve Realism

Humans think very highly of themselves (see egocentric bias!).

We tend to believe that we see the world with perfect objectivity (cognitive biases be damned!).

We also assume that people who disagree with us must be ignorant, uninformed, or biased.
Baader-Meinhof Phenomenon

Ever notice that something you just learned seems to pop up everywhere around you?

The Baader-Meinhof Phenomenon says that increased awareness of something creates the illusion that it is appearing more often.

Like seeing 11:11 on your iPhone clock...
Pygmalion Effect

High expectations lead to high performance (and vice versa).

Those who have high expectations placed on them are more likely to internalize these expectations and improve their performance accordingly.

Leaders may attempt to use this to their advantage.
Confirmation Bias

Humans have a tendency to see and interpret information in a manner that supports previously held beliefs.

New data positive? This idea is a slam dunk!

New data negative? Must have been an error in the experiment.

Very common and very dangerous.
Backfire Effect

The "backfire effect" is the tendency for humans to use evidence in direct conflict with their thesis to further strengthen their previously held beliefs.

It is a more dangerous version of confirmation bias (also less common and scientifically contested).

The "anchor" is a reference point of information (usually the first piece of information received on a topic).

All subsequent thinking or decisions are silently "anchored" to this point.

Anchoring has been proven by scientists (and used car salesmen) time and again.
Dunning-Kruger Effect

People with a low ability at a task are prone to overestimate their ability at that task.

Humans are notoriously incapable of objective evaluation of their competency levels.

Remember: Everyone is a genius in a bull market.
The Ben Franklin Effect

"He that has once done you a kindness will be more ready to do you another, than he whom you yourself have obliged."

Doing a favor makes you more likely to do another for that person than them doing a favor for you.

We reinforce our self-perceptions.
Loss Aversion

First identified by famed scientists Amos Tversky and Daniel Kahneman, it says the pain of losing something is more powerful than the pleasure of winning it.

As such, humans will typically do more to avoid losses than they will to seek gains.
Endowment Effect

Related to loss aversion, the endowment effect says that once we have something, we don't want to give it up.

Humans will demand more to give up an object than they would be willing to pay to acquire it.
Availability Bias

Humans evaluate situations based on the most readily available data, which tends to be what can be immediately recalled from memory.

This is how the news cycle impacts our thinking. Its persistent negativity cements a belief that the world is a dark place.
Survivorship Bias

History is written by the victors.

But concentrating on "survivors" and systematically ignoring "casualties" of any situation leads to distortions in our conclusions.

We overestimate the odds of success because we only read books about the successes!
The Ikea Effect

People ascribe significantly more value to objects that they have created or assembled, irrespective of the final quality of the object.

We infuse our own self worth into the object, thereby increasing its value in our minds.
Hindsight Bias

Humans tend to believe that events of the past were more predictable than they actually were.

We examine the past with the benefit of hindsight but fail to recognize its impact on our thinking.

Hindsight bias can meaningfully distort our memories.
Plan Continuation Bias

Humans love plans.

Even when the plan appears to be failing (or no longer an appropriate fit for a given situation), we have a tendency to want to continue.

The dangers of a rigid "stick to the plan!" mentality are very real.
The Gambler's Fallacy

Humans are naturally bad with probabilities.

The Gambler's Fallacy says that we have a tendency to believe that past events alter future outcomes (when they clearly have no impact).

Ever thought you were "due for a win" in roulette. You're falling prey.
Curse of Knowledge

Experts (or generally, intelligent people) tend to make the flawed assumption that others have the same background and knowledge on a topic as they do.

They are unable to teach or lead in an effective manner for those still coming up the learning curve.
Cognitive biases have a profound impact on our thinking and decision-making every single day.

The first step to fighting back? Awareness. I hope this post helped with that!

Enjoy this thread? Follow me @SahilBloom for writing on mental models, business, and more.
I will be turning this thread into a longer-form piece for my newsletter, where I will explore these biases in greater depth (including examples and ways to combat them!).

It will be released in the coming days.

Subscribe below so you don’t miss it!
And if you are a job seeker looking to leverage your improved awareness and decision-making skills to advance your career, check out my curated job board, where I share unique roles at high-growth companies in finance and tech.

New roles every week!…
This thread is going to become a multi-part newsletter series on cognitive biases, including examples of each and practical ways to combat them.

Part I will be released this week.

Sign up here so you don’t miss it:
The Cognitive Biases Handbook (Part 1 of 2) will hit inboxes tomorrow.

I hope it’s a free resource that you can save and come back to whenever you need a refresher!

Sign up here to receive it:
The Cognitive Bias Handbook

The newsletter deep-dive (part 1 of 2) is now live in your inbox and ears! Please enjoy, share, and subscribe if you haven’t already.…

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More from @SahilBloom

May 27
How to learn anything.

The Feynman Technique:

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The Feynman Technique is a learning method that prioritizes simplicity to build depth of understanding. Image
Feynman’s true genius was his ability to convey complex ideas in simple, elegant ways. Image
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May 26
My life improved dramatically when I stopped glorifying the wrong things.

What I used to glorify:
• No sleep
• 100-hour workweeks
• Busyness
• Doing more

What I now glorify:
• Sleeping 8 hours
• Daily physical activity
• Unstructured schedules
• Doing less, but better
There is a natural tension here:

A short period of focus on the former group may set you up to spend the rest of your life focused on the latter group.

The key is to avoid *glorifying* the former—thinking these things are the end, not the means to a better end.
My old definition of success was based on money and status.

My new definition of success is based on freedom and control of my energy.
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May 25
A monthly ritual that changed my life (and may change yours).

The Think Day: Image
In the 1980s, Microsoft founder Bill Gates began an annual tradition he called the Think Week.

Gates would seclude himself in a remote location, shut off all of his communication, and spend an entire week dedicated to reading, learning, and thinking.
The radical approach became an essential part of his process:

"Think Week is a time when I can be creative and push my own thinking. It's a time to step outside the day-to-day demands of my job and really focus on the big picture." - Bill Gates
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May 24
“PSA: 20 years from now, the only people who will remember that you worked late are your kids.”

I am of two minds on this:

1. Being present and spending time with those you love is the most important thing in the end.

2. Having the people you love see you work hard on things…… Image
My dad had impeccable mid-90s style:

- Aviators
- Casual rolled up sleeves
- Camera strap
- Long white socks
- Worn out low top sneakers
- Mustache

Absolute legend.
My view:

The goal is not to sacrifice our career, fail to live up to our professional potential, and stop growing in an effort to be constantly present with our kids.

The goal is to have the clarity to choose—to define your balance, to live by design, rather than by default.
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May 20
Harsh truths I know at 32 I wish I knew at 22.

1. Most of your friends aren’t really your friends.

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2. You’ll only see your loved ones a few more times.

3. You’ll literally never know what you want to be when you grow up.

4. Most people don’t really care about you. Image
5. You should never bet against a person who just keeps showing up.

6. You probably won’t be remembered or have a legacy.

7. You can tell everything you need to know about a person by observing how they treat service workers.

8. Showing up early pays off handsomely. Image
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May 17
This Reddit post hit me hard. Image
A few of the responses:

“The graveyard is full of ‘irreplaceable’ and ‘important’ people.”

“I don’t remember what I was working on, I can’t tell you why it was important. But I can tell you how my not being there made my kids feel.”

Really makes you think about tradeoffs. ImageImage
I am of two minds on this topic:

1. Being present and spending time with your children is the most important thing.

2. Having your children see you work hard on things you care about is a principle they’ll remember for the rest of their lives.

My goal is to balance 1 and 2.
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