Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Which personality traits are real? Stress-testing the lexical hypothesis, published by tailcalled on June 21, 2023 on LessWrong.

This post is also available on my Substack. Thanks to Justis Mills for proofreading and feedback!

Most scientific personality models are, directly or indirectly, based on the lexical hypothesis, which roughly speaking states that there is a correspondence between important personality traits and abstract behavior-descriptive adjectives. For example, the Big Five was created by having people rate themselves using words like "outgoing", "hard-working" and "kind", and finding patterns in these. It is neat that one can create models in this way, but the large amount of abstraction involved by using abstract adjectives raises huge questions about how "real" the personality traits are.

I have created a new personality test, currently named Targeted Personality Test. I have multiple goals with this test, but one of them is to investigate which personality traits are “real” without relying on the lexical hypothesis. I do this mainly by assessing lots of specific narrow behaviors, rather than abstract vague adjectives.

By the end of this blog post, I hope to have introduced some concepts that makes my approach make sense, and thereby enable you to understand this diagram I made summarizing my results:

The semi-formal understanding of what is going on in this chart is very long, so before we proceed, let me give a brief, vague indication of what you will be informed about:

Trait impact: a measure of how strongly the personality trait influences the various behaviors and thoughts that we would expect it to.

Factor model loss: a measure of how much the personality trait conflates different unrelated things together.

Correlation with lexical notion: a measure of how well-labelled the personality trait is. (You can mostly ignore this variable as all of the personality traits performed reasonably well on it.)

Easy-Goingness: An example

A conventional personality test such as the SPI-81-27&5 might measure your personality traits such as Easy-Goingness by asking you how well a few abstract statements describe you, e.g.:

I like to take it easy

I like a leisurely lifestyle

I have a slow pace to my life

It seems plausible that someone who agrees that such statements describe them would be Easy-Going in some sense, and indeed I bet this sort of measure can pass all sorts of criteria used by psychologists to evaluate the quality of the test.

So if it is probably valid by the standard criteria, what could go wrong that the standard criteria don’t test for?

Well, let’s imagine the sort of person who is Easy-Going. They probably tend to relax in their free time, e.g. watching TV, and they probably don’t get worked up about controversial stuff, and they probably don’t go above and beyond at work. Basically, a relaxed person who doesn’t get too stressed or excited about things.

When we call the person above “Easy-Going”, is this just a convenient label we use for someone who happens to have a constellation of traits like the above? Or are we saying that there is some underlying factor, like a motive to take it easy, which causes them to have these sorts of characteristics? Or maybe there are some underlying factors, but they are heterogeneous and “Easy-Goingness” lumps them together? These are the sorts of questions I tried to investigate.

My first step was to come up with a more concrete characterization of Easy-Goingness than abstract statements like “I like to take it easy” or “I have a slow pace to my life”. I did this by giving the SPI-81-27&5 test to a bunch of people, and then asking the people who score high and low in Easy-Goingness to describe an example of how they could be said to be Easy-Going. To give you a taste for the answers, one person who scored h...