When The Self Settles Down

Melissa Dahl observes that William James’ 1890 text The Principles of Psychology “is thought to be the first time modern psychology observed the idea that personality settles down, or stabilizes, in adulthood.” She points to the work of Paul T. Costa Jr. and Robert McCrae that seems to support that insight:

Costa and McCrae’s work has found that from about age 18 to 30, people tend to become more neurotic, more introverted, and less open to new experiences; they also tend to become more agreeable and more conscientious. After age 30, these same trends are seen, but the rate of change dips. “It’s not that personality is fixed and can’t change,” Costa said. “But it’s relatively stable and consistent. What you see at 35, 40 is what you’re going to see at 85, 90.”

This makes intuitive sense: It’s maturity he’s speaking of, really. In the body, physical maturity happens rapidly throughout childhood and adolescence, and then stabilizes once you’ve reached your adult height, for example. If at least half of personality has a biological basis, it makes sense that it would follow that developmental arc, too. And if many of our character traits are also influenced by our environment, well, think of all the changes that occur in adolescence and early adulthood: college, first jobs, first loves, frequent moves. Speaking (very) broadly, life tends to settle down in the 30s, so it makes sense that our personalities do, too.

“There’s nothing magical about age 30,” Costa said. “But if you look at it from a developmental view, you can see the wisdom of [William James’s provocative statement].” In adulthood, as our lives become more constant, “it’ll take some relatively powerful change in the environment” to change our behavior.

Recent Dish on life at mid-life here. Update from a reader:

I happened to read (again!) Patrick O’Brian’s Master and Commander last week. The passage below struck home, and now I see that it turns James’s science into poetry. It’s Dr. Maturin reflecting on a friend and former Free Irish co-revolutionary, James Dillon, whose personality has darkened with age, a life of secrecy, and increased responsibility as a naval officer:

What is more, it appears to me that this is a critical time for him, a lesser climacteric – a time that will settle him in that particular course he will never leave again, but will persevere in for the rest of his life. It has often seemed to me that towards this period (in which we all three lie, more or less) men strike out their permanent characters; or have those characters struck into them. Merriment, roaring high spirits before this: then some chance concatenation, or some hidden predilection (or rather inherent bias) working through, and the man is in the road he cannot leave but must go on, making it deeper and deeper (a groove, or channel), until he is lost in his mere character – persona – no longer human, but an accretion of qualities belonging to this character. James Dillon was a delightful being. Now he is closing in. It is odd – will I say heart-breaking? – how cheerfulness goes: gaiety of mind, natural free-springing joy. Authority is its great enemy – the assumption of authority. I know few men over fifty that seem to me entirely human: virtually none who has long exercised authority.