How does personality vary across US cities?

[-]Douglas_Knight9y60

this likely understates the magnitudes of differences in underlying traits across cities, owing to people anchoring on the people who they know when answering the questions

Sure, if there really are differences, this method probably underestimates them. But there are other phenomena that could create false differences, such as varying social desirability bias.

[-]JonahS9y20

Yes, this is something that I've wondered about quite a bit specifically in connection with the variation in conscientiousness and agreeableness by religion. I plan on partially addressing this issue by discussing some objective behavioral proxies to the personality traits in later posts.

[-]Daniel_Burfoot9y40

Five Factor Model (FFM) ... the model is founded on the lexical hypothesis:

I notice I am confused. I was sure that the FFM came out of doing the following simple procedure:

Give people a many-item personality survey
Do a PCA of the resulting data
Keep the top 5 eigenvectors
Label them with reasonably accurate adjectives that seem to describe the general drift of the vector

How wrong is this? How important is the "lexical hypothesis" part?

[-]Douglas_Knight9y40

That's right. The lexical hypothesis only comes in at step 1 by including questions like "I am [adjective]." We start with a vague theory in the questionnaire and apply dimension reduction. The lexical hypothesis is that language gives us a vague theory. We want as broad a theory as possible, so it is useful to combine questionnaires. Some sources claim that the original questionnaire was generated from language without questions from explicit theories, but I don't think that's correct.

[-]Qiaochu_Yuan9y40

Thanks for writing this! I really think people should be doing this (applying well-known algorithms to interesting datasets and seeing what happens) a lot more often overall, and it's on my list of skills I'd really like to learn personally. So I'd be interested to hear a little more info on methodology - what programming language(s) you used, how you generated the graphs, etc.

I'm pretty skeptical of making any connections to the Bay Area rationalist community based on Berkeley's conscientiousness score (which I think is interesting but not for this reason). There are 100,000 people living in Berkeley, and most of them aren't rationalists. And depending on how far back most of this data was collected, plausibly most of the Berkeley respondents were high school or college students (UC Berkeley alone has over 35,000 students), since for awhile that was the main demographic of Facebook users, and probably for awhile longer that was the main demographic of Facebook users willing to take personality tests. (Edit: But see Douglas_Knight's comment below.) In general I'd think more about selection effects like this before drawing any conclusions.

[-]JonahS9y60

Glad you liked it :-).

So I'd be interested to hear a little more info on methodology - what programming language(s) you used, how you generated the graphs, etc.

I used R for this analysis. Some resources that you might find relevant:

Practical Data Science with R has very nice introduction to exploratory data analysis.
Advanced R goes into more detail on the language.
The graphs were made using ggplot2.
I used the lme4 package for Bayesian hierarchical modeling. See, e.g. Getting Started with Mixed Effect Models in R.
Kaggle Kernels has some good sample scripts.

And depending on how far back most of this data was collected, plausibly most of the Berkeley respondents were high school or college students (UC Berkeley alone has over 35,000 students), since for awhile that was the main demographic of Facebook users, and probably for awhile longer that was the main demographic of Facebook users willing to take personality tests.

Douglas_Knight is correct – the average age of users is quite low, at ~26 years old both for the high conscientiousness cities and the low conscientiousness cities.

[-]Qiaochu_Yuan9y20

Thanks for the links!

[-]taygetea9y40

I think you have the causality flipped around. Jonah is suggesting that something about Berkeley contributes to the prevalence of low conscientiousness among rationalists.

[-]JonahS9y60

What I had in mind was that the apparent low average conscientiousness in the Bay Area might have been one of the cultural factors that drew rationalists who are involved in the in-person community to the location. But of course the interpretation that you raise is also a possibility.

[-]taygetea9y00

Ah, I spoke imprecisely. I meant what you said, as opposed to things of the form "there's something in the water".

[-]John_Maxwell9y00

Previously on LW: Self control may be contagious

[-]Douglas_Knight9y40

Actually, two of your complaints cancel out. You should expect that the population living in Berkeley has a very young personality, but if all the data is from college students, then there's nothing special about Berkeley (except that it is large and thus small effects are statistically significant — but the claim is that it has a large effect).

I think you are correct that the data is all college students (or at least fairly young people). I believe this because the cities being discussed are the hometown, not the current residence, which is the kind of thing you'd do with college students. In any event, studying hometown controls for the age demographics of Berkeley. But Jonah should have explicitly controlled for age.

Added: poking around the website I don't see a clear answer to how old the data is. Most of it seems to have been collected by 2011, but I'm not sure because there are lots of variations. Each big5 score is labeled with the date taken.

[-]Qiaochu_Yuan9y00

I think you are correct that the data is all college students (or at least fairly young people). I believe this because the cities being discussed are the hometown, not the current residence, which is the kind of thing you'd do with college students. In any event, studying hometown controls for the age demographics of Berkeley. But Jonah should have explicitly controlled for age.

Good point, I missed this.

[-]Lumifer9y40

A vote of approval for messing around in data :-)

[-]DavidRV9y20

Fascinating that the high-extroversion cities are places I know well, while the low-extroversion cities are places I've never heard of.

[-]devi9y20

However, this likely understates the magnitudes of differences in underlying traits across cities, owing to people anchoring on the people who they know when answering the questions rather than anchoring on the national population

I think this is a major problem. This is mainly based on taking a brief look at this study a while back and being very suspicious of it explicitly contradicting so many of my models (eg South America having lower Extraversion than North America and East Asia being the least Conscientious region)