15 January 2022 | New Scientist | 47experience, suggesting I prefer novelty to
routine and the big picture to details. I also had
reasonably high scores on extroversion and
agreeableness, but was a bit low on emotional
stability, suggesting that I am prone to anxiety,
in particular. Finally, on conscientiousness,
I got a deeply unimpressive 44 out of 100,
despite a high score on its component related
to productivity. The overall trait result was
dragged down by my score on the component
to do with organisation: a shameful 6 out of- “You’d make an ideal academic,” says Brent
Roberts, a psychologist at the University of
Illinois, when he reviews my results.
Shifting traits
My personality type is partly down to my
DNA, with studies of twins showing that genes
can explain about half of the differences in
personality traits. The flipside is that there is
plenty of scope for experiences in adulthood to
leave their mark. Indeed, although many of us
assume our personalities are set in stone once
we reach a certain age, psychologists have
demonstrated over the past two decades that
personality traits change over a lifetime.
One study by Roberts and his colleagues
showed that, on average, we increase on
measures of nearly all the personality traits
between 20 and 40 years of age. Between
40 and 60, we continue to become more
conscientious and emotionally stable, while
agreeableness rises after 50. Beyond the age
of 60, we become less open and extroverted,
and more conscientious, perhaps as a result
of shrinking social circles.
The changes are pretty big, too.
Psychologists often measure personality
change in terms of “standard deviations”,
with a shift from being maximally introvert to
maximally extrovert equating to a difference
of about three standard deviations, for
example. According to Roberts, specific traits
shift by up to one standard deviation across
the course of someone’s life, especially
conscientiousness and emotional stability.
Change can occur over shorter time
intervals, too. In 2017, Roberts and his
colleagues analysed 207 previously published
studies on the efficacy of psychological
treatments, which simultaneously tracked
participants’ personalities. They found people
who had successful treatment for conditions
such as depression, anxiety and eating
disorders became not only more emotionally
stable, but also increasingly extroverted and
open during the course of the intervention.
These changes, of up to half a standardyears or decades, as opposed to those that vary
over shorter timescales such as days or hours.
But measuring personality is tricky. These
days, most psychologists use the Big Five
model, which divides our personalities
into five independent traits: extroversion,
agreeableness, conscientiousness, openness
to experience and neuroticism, otherwise
known as emotional stability.
The Big Five model has its critics. It was
developed based on a statistical technique
called factor analysis, which showed that words
used to describe personality in surveys could
be grouped into five distinct traits. Some
researchers have an issue with the lack of
a deeper, underlying explanation for this
arrangement. Others argue that it can’t
capture all aspects of personality, including
“dark traits” such as psychopathy or
Machiavellianism – or even humour.
Even so, as the most widely accepted among
psychologists, the model forms the basis for
much of the research into personality.
The Big Five traits are typically assessed by
questionnaires, which ask people about their
thoughts, feelings and behaviour. This involves
agreeing or disagreeing with statements such
as “tends to be lazy” or “is efficient, gets things
done”. And this is where my personality
modification started, with a test called
the Big Five Inventory-2.
I got a maximum score on openness to>“ People can
change pretty
dramatically
pretty fast”