Learning path

Think clearly: thinking errors and better decisions

The mental shortcuts that mislead everyone, how to judge risk and chance, why memory can't be trusted as a recording, and a checklist for big decisions.

7 lessons, about 42 minutes in all. Take them in order.

Printable cheat sheet

Mental shortcuts that mislead 6 min
Your mind judges how likely something is by how easily examples come to mind and how typical it looks. Both shortcuts are quick, and both can steer you wrong.
The first number sticks: anchoring 6 min
A number you see first pulls your estimate towards it, even when it is plainly irrelevant. Learn to spot anchors in prices, offers and forecasts, and set your own.
Seeing what you expect: confirmation bias 7 min
We look for, notice and remember evidence that fits what we already believe. Learn to test your ideas by looking for what would prove them wrong.
Read risk figures correctly 5 min
"Doubles your risk" can mean almost nothing, and a positive test can still mean you probably don't have the disease. Turn percentages into counts of people to see what a risk figure really says.
Memory is rebuilt, not replayed 5 min
Each time you remember something, your brain rebuilds it, and later information can slip in. Learn why confident memories can be wrong, and how to protect what you remember.
Framing and the fear of losing 7 min
The same facts described as gains or as losses lead to different choices, because losses hurt more than equal gains please. Learn to reframe a choice both ways before you decide.
A checklist for big decisions 6 min
Knowing about thinking errors doesn't stop them; a routine does. A short checklist, with the outside view and a pre-mortem, catches most of the errors in this path before they cost you.

Try it for real

Keep a decision journal for one week

Thinking errors are easiest to catch on paper. For one week, write down every decision that matters to you, then check it against the tools in this path. This is practice in noticing how you decide, not a test.

You need: a notebook or a notes app, and about ten minutes a day.

Steps

Pick decisions with something at stake: a purchase over a set amount you choose, a plan at work or school, something you agreed to, an argument you took a side in. Aim for at least three over the week.
Before deciding, write: the decision, your options (at least three), what you expect to happen, and how sure you are, as a percentage.
Run the checks from the decision checklist: where did your numbers come from (anchors)? What would change your mind, and did you look for it? How does it look framed as a gain and as a loss? Do a two-minute pre-mortem on the biggest one.
Watch for risk figures in news or adverts this week. For one of them, find the absolute risk ("out of how many?"), as in Read risk figures correctly.
At the end of the week, reread your entries. Note one decision where a check changed what you did, or would have.
In a month, reread them again and compare what happened with what you expected and how sure you were.

Check yourself

I wrote down at least three decisions before making them, with my options and how sure I was.
I ran the checklist questions on at least one decision.
I did at least one pre-mortem.
I found the absolute risk behind one relative risk figure I saw this week.
I noted one place where a check changed, or would have changed, my decision.
I set a reminder to reread my journal in a month.

Nothing here is graded or saved: the checklist is for you.