When Do Personality Traits Predict Behavior?

Personality can predict behavior, but only when we understand its limitations.

Posted Oct 02, 2018

Wikimedia Commons
The "Big 5" Personality Traits
Source: Wikimedia Commons

Psychologists have been studying personality for a very long time. Thinking about personality as a collection of traits goes all the way back to ancient Greece and Rome, and trait theorists such as Gordon Allport, R. B. Cattell and Hans Eysenck shaped the study of personality throughout much of the 20th century.

However, the failure of personality traits to consistently predict actual human behavior in experiments throughout decades of research was discouraging, and, in the 1970s, psychologists such as Daryl Bem and the late Walter Mischel began to seriously consider the possibility that the consistency of personality traits was just an illusion, and that it was actually the strength of situations, not personality, that controls how we behave most of the time.

Let me illustrate this point of view with an example.

When I teach one of my college courses, my students (at least the ones who attend class regularly!) see me three times a week for 70 minutes at a clip, over a span of ten weeks.  Given this amount of exposure, I am sure that if someone asked any one of these students to describe my personality, he or she would do so with confidence and there would probably be a fair bit of agreement among my students about the kind of person that I am.  The consistency and confidence of their judgments would understandably bolster the belief that the personality traits that they see in me are stable and real.

However, there is an alternative explanation.

These students are seeing me in exactly the same situation over and over again – the same room, the same activity, the same time of day. What if they are actually seeing nothing more than how any person in my shoes would behave in that situation? In other words, because we tend to see people in the same circumstances over time, we delude ourselves into thinking that we have insights into which traits are most important to their personalities.

Since the 1970s, new statistical tools fueled by the development of computers and more sophisticated research methodologies have convinced most psychologists that personality traits are indeed real and that, at least sometimes, they can be valuable predictors of behavior.  The trick now is to understand under exactly what circumstances they can be effective.  The information I am about to share is based upon the consensus of hundreds of different studies over the past 30 years.

The more specific and limited the trait, the better a predictor it is.

One of the problems with early personality research was that it often relied heavily upon the measurement of very broad traits such as self-esteem, and the usefulness of broad traits for predicting specific behaviors is limited. 

For example, suppose that I am interested in predicting ahead of time who might volunteer to pose nude in front of art classes when our college's art department advertises for models.  It makes intuitive sense that a measure of self-esteem might be able to help me, since people who feel good about themselves might be more willing to volunteer for such a thing.  The problem with self-esteem, however, is that it is so multi-faceted.  A person can have high self-esteem that rests on very different things, such as academic or athletic ability, social skills or physical beauty, and a generalized measure of self-esteem conflates all of these different factors.  In this case, a more specific measure of self-esteem, such as “Body Esteem,”  would prove to be a much better predictor.

The more extreme a person is on a particular trait, the better a predictor it is.

We all have a tendency to speak about personality traits as if they were categorical in nature, as when we describe someone as being either an introvert or an extrovert.  In reality, these traits are continuous variables like height or age, and we all fall somewhere along the line between being an extreme introvert or an extreme extrovert.  One is only introverted or extroverted in comparison to someone else, just as one is only old or young (or tall or short) in relation to someone else.  Research has shown that the more to one of the extremes a person falls on a trait, the more consistently that trait will be a factor in his or her behavior.  If you score in the middle of the dimension somewhere, the odds are that other factors likely play a more important role in determining your behavior.

Traits predict general patterns of behavior over time better than single instances of behavior.

Another problem with some of the early personality research was that it often measured a personality trait and then used it to predict a person’s behavior in a single experimental session.

We now know that personality traits are better at predicting long-term behavior patterns.

Suppose that I gave you a personality questionnaire that revealed you to be an extreme extrovert.  If I wanted to check how accurate this assessment was, I might follow you to a social event next weekend where I would expect to see you be the life of the party, surrounded by minions who adore you.  Imagine my surprise, however, if I were to find you sitting alone in a corner crying in your beer instead.  In a single situation, there are simply too many other factors that might be at play for your personality to determine what happens.  Powerful events, such as the death of a dog or being dumped by a boyfriend or girlfriend, can easily overwhelm your natural social inclinations and cause you to behave in ways that are totally out of step with your extroversion.

On the other hand, if I were to follow you to every social event you attended over the next six months, I would see your extroversion coming through more often than not, and I would then feel more confident that this trait does indeed exert influence over your behavior.

More specific situations make traits better predictors.

For most of my adult life, I have owned a dog. I frequently walk my dog around town and on the college campus where I work, and I am regularly approached by people who are interested in meeting the dog.  One of the most common questions that I am asked is “Is your dog friendly?”

This can be a tricky question to answer, because it is not specific enough.  Some individuals want to know if my dog will try to bite them if they pet it; others want to know if they should be prepared for the dog to jump up on them and lick their faces.  Sometimes, people just want to know if my dog is friendly with other dogs, and if our two dogs are likely to get into a fight if we let them get too close together.  Hence, I cannot answer the question very easily unless I know exactly what situation my new acquaintance is interested in.

This conclusion will make perfect sense to most of my readers, as you are well aware that you often act differently in social situations with friends as opposed to relatives or strangers. So, your prediction as to how you will behave will be more accurate if you can place it in a specific context.

In short, the evidence is that personality traits can be good predictors of behavior as long as we understand the constraints that they operate under. 

Predicting behavior over longer periods of time and in precise situations will be best, especially if we are using very specific measures of traits that a person scores extremely high or low on.  This means that different traits make for better predictors for different people.  A trait that is important for predicting your own behavior is referred to as a “self-schematic trait,” while traits that are less relevant for you are known as “aschematic traits.”

And always remember that no matter how good a personality trait may potentially be as a predictor, it can still be overpowered by strong factors in a situation. 

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