How Personality Psychology Thinks About Prediction Today

Last time, I wrote that, because our behavior is often inconsistent and unpredictable, personality psychologists include some form of randomness in their models (and I mean randomness in the “well, that was totally random” sense). Today, I briefly want to outline some findings from Fleeson (2001), the paper that most clearly ushered in this approach.

In Fleeson’s work, every 3 waking hours for 2-3 weeks people answered how well personality terms (such as talkative and creative) described them in the last 1 hour. Fleeson found a number of interesting things:

1. High variability. People’s behavior is all over the shop. Extraverts don’t always act extraverted, they act introverted too. Each three-hour window was unlikely to match the preceding three-hour window. Put positively, our personality doesn’t always constrain us. Put more negatively, we rarely use the same words to describe ourselves across the course of a day.

2. Stable means. One person’s average behavior is roughly the same over the length of several weeks (compared to someone else’s). For example, extraverts tended to have roughly the same average level of extraversion across the weeks.

3. Stable variation. A person’s amount of variability tends to stay consistent over time. If a person shows really large variability in how open they are to experience, that variability will stay large over the weeks.

4. Trait driven. Over time, the consistency in averages and variation are only true for the same trait, not for different traits. For example, the mean of my extraversion doesn’t relate to the mean of my conscientiousness over time.

These findings are all simultaneously true. We are both random (every three hours) and predictable (across the weeks). For me, they also raise a whole bunch of interesting questions. For example, is personality just not real at all? Or is personality not really about our everyday behavior?

There are many, many things we can think about with those data, and I leave you to ponder them for yourself. Remember, the study simply asked people “During the previous hour, how well does [Trait X] describe you?”, it didn’t measure other things.

I only often one reflection right now. I tend to think that personality is just not about everyday behavior. I am reminded of a quote by Charlotte Brontë in Chap. 27 of Jane Eyre:

“Laws and principles are not for the times when there is no temptation: they are for such moments as this, when body and soul rise in mutiny against their rigour”

I wonder if we can paraphrase that a little:

Personality is not for times when life is routine, it is a guide for when we enter the extra-ordinary, be it through novelty or conflict.