Personality through life

We all differ in our thinking skills and we all differ in our personalities. As part of our Staying Sharp series, Dr René Mõttus of the University of Edinburgh explores whether the two are related.

What is ‘personality’?

As people, we all differ in how we typically think, feel and behave. These patterns make up our personality. Personality is at work in almost everything that we do. It’s a major part of what makes us who we are as individuals and how we come across to others.

Numerous characteristics, or “traits”, contribute towards personality. They are often grouped into five categories, shown here with examples of traits within them:

• Openness - open to new experiences, adventurous, creative.
• Conscientiousness - reliable, self-disciplined, diligence.
• Extraversion - being active, outgoing, positive.
• Agreeableness - being trusting, co-operative, kind to others.
• Emotional stability - emotion, mood, anxiety level.

Thinking skills and personality – what’s the link?

Thinking skills and personality are complex and are highly individual from person to person. They make us all different, and unique.

We know that people’s thinking skills, e.g. the ability to quickly solve mental tasks, change with age. Research psychologists have asked whether these changes are linked, first, to personality characteristics and, second, to change in the characteristics over time? The answer is, not necessarily.

To answer the first question, when individuals are compared to each other, we find that most personality characteristics do not link to cognitive abilities. There is perhaps only one clear exception: people who are quicker in thinking also tend to be more open to new experiences. Other than this, snappy thinking seems to have little relevance for what people typically do in their lives, and vice versa.

Changing together in ageing?

Let’s look at the second question.

Personality characteristics do change, but not much. For example, many people become somewhat more agreeable as they get older, but this does not apply to everyone or at every stage of life.

From research so far, there is not much clear evidence that thinking skills, or changes in them, are linked with personality changes over time.

For example, it does not seem to be the case that being a quick thinker means that you are more likely to experience any one particular pattern of change in personality than another. To explore this idea further, we studied patterns of personality change and cognitive ability in the Lothian Birth Cohorts of 1921 and 1936 (the people participating in the Age UK funded Disconnected Mind research project).

We found that higher cognitive ability was associated with less decline in conscientiousness in one group but this pattern did not emerge in the other group. Neither did we find any clear evidence that the two were changing together; in other words, cognitive abilities and personality characteristics were not in lock-step.

What about the other way around: does personality influence the way our thinking skills change with age? Studies have found that high emotional stability and conscientiousness predict lower probability of substantial cognitive decline in later life. But we don’t yet know whether this is because of a direct relationship between these personality characteristics and cognitive ability, or whether the characteristics act through some other mechanism that protects against cognitive decline. Future studies have to tackle this question.

Are there other factors that could predict changes in personality characteristics? Again, there is not much clear evidence yet. For example, we have attempted to link personality changes to physical health – with little success so far.

Staying who we are

Although there are still many questions to answer, what we know so far could be good news. Perhaps it is good to think that, whatever other changes people experience as they age, our personality stays fairly much the same - meaning that we retain the individuality that is at our very core.

Key references

• Mõttus, R., et al., 2012. Correlates of personality trait levels and their changes in very old age: The Lothian Birth Cohort 1921. Journal of Research in Personality, 46(3), pp. 271-278. 
• Mõttus, R., et al., 2017. Markers of psychological differences and social and health inequalities: Possible genetic and phenotypic overlaps. Journal of Personality, 85, pp. 104-117. 
• Terracciano, A., et al., 2014, Personality and risk of Alzheimer's disease: New data and meta-analysis. Alzheimer's & Dementia: The Journal of the Alzheimer's Association, 10(2), pp. 179-186.