Imagine I am paying you \$5 to guess what subject I was studying at university.

• It might help for you to make a guess right now! It might be even more helpful to note down what information you use to inform your guess.

... ... ... ... I studied computer science. What did you guess? Based on what information? The last time I asked someone from my university that question, they guessed that I was studying philosophy, because "I looked like I was studying something in the humanities."

This is a common way for people to guess. Even though this person had only looked at me on the outside and knew nothing else about me, he used this information of representativeness to guess my subject. Given that he knew I was attending a technical university, he could have guessed any engineering degree and would have had a higher chance of being right. Had he made his guess based on which subject is the most popular at my university (computer science) he would have been right.

Human reasoning developed in small tribes, in which you would have already known all relevant statistics like these on a visceral level. You would not have made a wrong guess like this because you would have already known the person. In the 21st century, not only is the world larger than we can wrap our heads around, but the internet has made information cheap, and it might be worth reading.

So the next time you are making a large important decision on little data, perhaps ask yourself if you already know a more reliable source of truth here, or if you might get better data through 5 minutes of googling.

The more advanced version of this includes acquiring information before it becomes relevant. Or noticing that you already know everything you need. Another good habit is to stop reading people's prose and instead interpret data on your own.

Optional Exercise:

Open https://ourworldindata.org/, choose a topic you do not know enough about and note things you find surprising in the graphs. If something is sufficiently surprising ask yourself how this might point to even larger gaps in your understanding of the world.