Think back to how you behaved as a teenager. Are you cringing? Many of us feel very different to the person we were ‘back then’. But are you different? And what will you be like in old age?

How much does your personality change over a lifetime? Image modified from vanes_hud via Flickr and Neill Kumar via Unsplash

Who are you?

Have you ever done a personality test? I have: I was intrigued to find out if answering a few dozen questions could give an accurate picture of who I am. Whether Myer-Briggs, the Big Five, or HEXACO, decades of research have gone into validating personality questionnaires. And millions of people take these tests every year.

The tests all attempt to do the same thing – characterise your personality according to some key traits. How extraverted are you? How conscientious? How neurotic? How intuitive? How open are you to new ideas? And the general consensus has long been that our personalities are pretty constant through time: once an extravert, always an extravert. If you watched Seven Up!, you might remember the premise – ‘Give me a child until he is seven and I will show you the man’.

But think back over your own life – do you feel like the same person now as you were in your twenties? How about in your teens? Or when you were only seven? It turns out the idea we’re stuck with certain personality traits for our whole lives may be rubbish.

In it for the long haul

To get an idea of how personality changes over time, we need to study people over many years. There have been a few of these longitudinal studies. One analysed the personality of a group of men in their mid-forties and again in their mid-seventies. Another followed a large group of Hawaiians from primary school through to middle-age, 40 years later. But the longest-running personality study of them all has just been published – it’s been running for a whopping 63 years.

The study started in 1947 when 1,208 14-year old Scottish students were rated by their teachers on six personality traits: self-confidence, perseverance, stability of moods, conscientiousness, originality and desire to excel. The ratings were put together into a single measure of dependability. Fast-forward 63 years and 174 members of the original group were located and agreed to take part in the study. They rated themselves on the same six traits and also asked a close relative or friend to do the same.

Now it’s obviously not the perfect study: only a small group of people and you can imagine the teachers might have been much better at scoring some traits than others. But it still gives us some insight into how similar – or different – these people were at the ages of 14 and 77.

Turning over a new leaf

It’s a fair bet you’ve changed your dress sense and taste in music since you were a teenager. But the Scottish research suggests you may have changed in other more profound ways too. Over the 63 years of the study, many of the participants changed so much that their former personalities were barely recognisable. There was some similarity between the 14 and 77-year olds in terms of how conscientious and generally stable each person’s moods were. But beyond that, at least in terms of personality, the older Scots had very little in common with their former selves.

And if you’re guessing all the changes probably happened during the twenties or perhaps around fifty, think again. Nearly a quarter of the 23,000 people who took part in a German study changed personality drastically after the age of 70. Why such big changes? There are lots of things that can affect your personality: for example, your job, where you live, becoming a parent, being in a relationship and experiencing trauma. And some changes simply happen with the passing of time. Research involving more than 130,000 adults showed we tend to become more agreeable, conscientious and emotionally stable as we get older.

So whether you like it or not, you’re likely to turn over at least one new leaf during the course of your life. Hopefully the fact you’re also going to become more agreeable means you’re going to like the person you become.

Links and stuff

• This week I’ve teamed up with all-round funny guy Dr Andy Stapleton.  For his take on this topic, check out Just because you’re a dickhead now, it doesn’t mean you’ll be one forever.
• NPR: Personality can change over a lifetime, and usually for the better
• The Atlantic: How to change your personality
• Invisibilia podcast: the Personality Myth

This post was selected as an editor’s selection on scienceseeker.org