We’ve all seen a million different personality tests online.
Some appear to take a relatively scientific route, while others are blatantly frivolous,
telling you which Harry Potter character you are, or even worse, what kind of sandwich. But what is
personality? Psychologists define personality as the specific thoughts, feelings, and behaviors
a person exhibits. Are you generally optimistic or pessimistic? How do you interact with your
environment? In general, personality is stable across your lifetime, and people usually react
to situations in ways that are consistent with their underlying personality traits.
People have been thinking about what causes personality for a long time.
Way back in the 1st and 2nd centuries CE, the Roman philosopher Galen believed that personality
was the result of different levels of ‘humors’, as we touched upon in the History of Drugs series. In
Galen’s view, the four humors found in a person’s body, blood, phlegm, black bile, and yellow bile,
controlled one’s personality. Different levels of these humors were responsible for different
personality traits. For example, cheerful people were believed to have an excess of blood,
while shy people had a lot of phlegm in their bodies. Although psychologists today certainly no
longer believe that we have humors which control our personalities, they do think, like Galen did,
that personality has biological roots. Let’s explore this idea a little more.
How is our personality related to our biology? Well, your adult personality emerges in part
from the temperament you exhibit as an infant. Temperament is the biological and instinctive
part of personality that is present at birth. There are four major dimensions of temperament.
First is activity level. Second is impulsivity, or time taken to express emotion.
Third is positive emotionality, meaning smiling, laughing, and sociability. And lastly there is
negative emotionality, meaning irritability and fearfulness.
The temperament shown in infants turns out to predict adult behavior and personality.
More reactive infants tend to be more anxious in adulthood. This link strengthens the argument that
personality is in part biological. In addition, research suggests that these temperament traits
arise from biological underpinnings like genetics. For example, some personality traits seem to be
heritable, and identical twins have very similar personalities, even when raised apart. Of course,
while the biological temperament of infants plays an important role in determining personality,
it is also impacted by the environment. How a parent interacts with their child
can shape how genes are expressed and the eventual personality that is displayed.
Now that we know more about how personality is in part determined by biology, let’s dig deeper into
the different parts of personality. Psychologists today generally agree that there are five core
dimensions of personality, also known as The Big Five. We can remember these five dimensions using
the acronym OCEAN: openness, conscientiousness, extraversion, agreeableness, and neuroticism.
Each of these dimensions represents a continuum between two extremes. For example, extraversion
is the range between extreme extraversion and extreme introversion. Most people fall somewhere
in between the two ends of each dimension. Let’s go through each dimension in a little more detail.
Openness is the spectrum dealing with things like imagination, insight, and willingness
to try new experiences. People who are high in openness tend to have a broad range of interests,
are very curious about the world, and like to try new things. They tend to be very creative as well,
and like tackling new challenges. On the flip side, people low in openness dislike change and
are resistant to new ideas. They also tend to be more traditional in their thinking and do not like
dealing with abstract or theoretical concepts. Conscientiousness deals with impulse control
and goal-directed behaviors. Highly conscientious people tend to be highly organized. They spend
time preparing for tasks and finish important tasks right away. They also tend to enjoy having
a set schedule and are mindful of how their behavior affects others. In contrast, people
low in conscientiousness dislike structure and schedules. They tend to make messes and not put
things away. They also procrastinate on important tasks and often fail to complete required work.
Extraversion is the trait dealing with excitability, sociability, and emotional
expressiveness. This is the trait that you’re most likely to have heard other people talking about:
are you an introvert or an extravert? People who are high in extraversion like to be the
center of attention and are energized by being around people. They enjoy meeting new people
and have a wide social circle. People low in extraversion, meaning they are introverted,
are more reserved and tend to feel exhausted after lots of socializing.
They also find it difficult to start conversations and don’t like being the center of attention.
Agreeableness is the personality continuum dealing with prosocial behaviors
like trust, kindness, and affection. People high in agreeableness enjoy helping others
and feel a lot of empathy and concern for other people. They tend to be very cooperative,
and often assist others who are in need of help. In contrast, people low in agreeableness
tend to be more competitive and can even be manipulative when trying to get what they want.
They take little interest in others and don’t care about how people feel.
Finally, neuroticism deals with moodiness and emotional stability.
People high in neuroticism tend to experience mood swings, anxiety, irritability,
and sadness. They get upset easily and often struggle to bounce back after stressful events.
On the other hand, people low in neuroticism deal very well with stress and tend not to worry much.
They are more emotionally stable and rarely feel sad or depressed.
Together, these Big 5 personality traits shape our overall personalities, regardless of where we’re
from. One study found that these five personality traits could be used to describe personality in
more than 50 different cultures worldwide. They are also heritable. Between 42% and 57%
of a person’s score on these traits is decided by genes. This makes sense if you
think about twins. Even though identical twins are extremely similar genetically,
they still have different personalities. Their genes are explaining part of their personality,
but things like the environment and interactions with others are also shaping their personality.
The Big 5 personality traits are also pretty stable in adulthood. As you age, your personality
solidifies, especially after you reach 30 years old. Even when people go through adverse life
events, their overall personality shows little change. In part because they are so stable,
the Big 5 are also able to accurately predict people’s behaviors. For example,
conscientiousness predicts marital fidelity, and openness to experience predicts job changes.
People high in extraversion are more likely to look people in the eye during conversations.
Don’t forget, though, that behavior arising from personality is situational. People can
behave in ways contrary to their personality if they are put in an extreme situation. However,
in most cases people react to situations in ways that are consistent with their personality traits.
Before we move on from personality, we should take a moment to talk about a personality test you’ve
probably heard about and may have even taken: the Myers-Briggs. The Myers-Briggs test is the one
that classifies people based on four different categories: extraversion vs. introversion,
sensing vs intuition, thinking vs feeling, and judging vs perceiving. The Myers-Briggs
is popular, and people all over have proudly classified themselves as ‘ENTPs’ or ‘INTJs’.
Unfortunately, the Myers-Briggs is incredibly flawed for multiple reasons.
First up, Myers-Briggs relies on binaries, giving an oversimplified view of human
personality. You are either an introvert or an extrovert, with nothing in between.
This is totally different from what we talked about with the Big 5, which is based on the
much more accurate idea that personality traits fall on a spectrum. Myers-Briggs
also completely overlooks some key personality traits. For example, it doesn’t measure emotional
stability or reactivity at all, something that is measured in the neuroticism trait in the Big 5.
The judging-perceiving scale in Myers-Briggs also doesn’t measure traits like achievement drive
or industriousness, which are key parts of the personality trait conscientiousness in the Big 5.
Because Myers-Briggs is so incomplete and oversimplified, it isn’t a reliable predictor
of personality at all. Around 50% of people are classified as a different personality type the
second time they take the Myers-Briggs. And even though lots of jobs use it as a interview tool
or as a way to improve workplace dynamics, Myers-Briggs does not predict job success.
So where does that leave us? Well, the Myers-Briggs is a fun test to take, and it can
start to give you some insight into yourself and how you relate to your world. But if you really
want to understand your personality, you should instead look at your Big 5 personality traits.
They will actually help predict your behavior and help you better understand yourself.