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The link between low conscientiousness and mortality

Bad news for the less diligent among us: it is taking years off our lives.

Imagine there was an app that could predict your moment of death. Given that there’s apparently one for everything else, we might readily think this was possible.

The existence of such an app is the premise of the 2019 horror flick Countdown, in which the protagonist tries to cheat her predicted death. I haven’t seen the movie, but a Rotten Tomatoes score of 26% suggests it’s about as good as an app that claimed to predict your time of death would be.

In the absence of an app for the task, let me help you out by explaining how your psychology may predict mortality. Never say this column doesn’t give you something you can apply in your life or, in this case, death.

Consider personality. We all have an intuitive sense of what a “personality” is, and in psychological research and practice, the most common view is that it describes the relatively stable ways we move through the world and appear to other people.

It can be summarised under five broad headings: extroversion, agreeableness, openness to experience, neuroticism (or, slightly less pejoratively, emotional stability) and conscientiousness. We all have them to some extent or other.

Which of them might predict death, though? Extroversion relates to how outgoing and sociable we are, and we’re always being told that social relationships are good for you. Candidate No 1, then. Neuroticism predicts depression, so that doesn’t sound too unreasonable. Agreeableness reflects how collaborative, altruistic and empathic we are, so …?

To test the part played by each of these, we need a particular type of information. We need to know a little about people’s personality before they die and then whether and ideally when they did (or didn’t) die. Fortunately for Markus Jokela and colleagues at the University of Helsinki, there are a small number of very large longitudinal studies that allow exactly that.

Markus Jokela. Photo/Linda Tammisto

When Jokela’s team controlled for other things that we know are also associated with premature death, such as obesity, smoking and lack of exercise, it turns out that personality is a relevant predictor of “all-cause mortality”. Sure enough, less extrovert and agreeable and more neurotic individuals were more likely to die sooner.

Although these are the pillars of personality, they also lean on each other a little, and that means that when they all went into the statistical pot, one personality trait came to the fore – conscientiousness.

Aiming for a big reveal, I haven’t had much to say about conscientiousness so far, but it’s pretty straightforward. The more conscientious you are, the more organised, responsible and self-controlled you are.

Of course, people who aren’t particularly conscientious are also less likely to follow their doctor’s health advice, stick to exercise regimes or avoid doing things that they know aren’t good for them. But even after controlling for lack of exercise and all those other things that are themselves potentially influenced by conscientiousness, it’s a uniquely important predictor.

Jokela and his collaborators estimate that if your conscientiousness score tips you even slightly into the lowest sixth of the population, that means a 14% increase in your risk of all-cause mortality (an average of about six years less of life). They speculate that if we could “make” people more conscientious, it would mean as much as an 11% decrease in deaths.

They do hint at the fact that we don’t really have a good handle on whether and to what extent it is even possible to change something that is part of who we are – our personalities can change, and they do change, but they don’t change quickly.

So, perhaps as you might also expect from a death-predicting app, I’ve overpromised and under-delivered. What does a 14% increase in risk even mean, particularly if there’s not much you can do about it?

My advice is just cut down on the smoking and drinking and do a little more exercise.

This article was first published in the March 7, 2020 issue of the New Zealand Listener.

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