For more than 2000 years, philosophers and psychologists have been interested in individual personalities, how they form, and what makes one person different from another. The first attempt to categorize personality types came from the Greeks, which organized four personality types:
As time passed, however, later generations of psychologists found these categories to be wholly inadequate, and they soon formulated new personality types. Personality research began to take off in the 1940s when Hans Eysenck, a German-born psychologist who left Germany during the Nazi era, published “Dimensions of Personality” in 1947. As pointed out by Tom Bowdon, “Eysenck believed that these supertraits were genetically determined and were manifested in our physiology, specifically the brain and nervous system.”
Eysenck ditched the Greek system and “was in debt to Carl Jung’s distinction between introverts and extraverts,” but he took a statistical, quantifiable approach to personality types. In short, Eysenck developed the PEN model of personality types. It looks like this:
Eysenck’s PEN model has several distinct characteristics; namely, the model centers on the individual’s brain chemistry and how that chemistry influences one’s personality. Finally, although in recent decades Eysenck’s personality model has been replaced, it was important because it was one of the first personality models to use a scientific approach as its basis.
In the years since Eysenck’s PEN personality model, psychologists have been refining their approach. According to Christian Jarrett, “Contemporary psychology has now settled on the idea that there are in fact five main factors to personality, known as “The Big Five.” They are:
The key idea about The Big Five remains that individuals do not fall into a single personality, as Jarrett points out, but rather elements of each category exist in varying levels in each of us. In other words, “The big five factors are continuous dimensions like height and weight,” Jarrett writes. “So it’s not the case that we’re either neurotic or we’re not. Rather, we each have a certain amount of neuroticism, and so too for the other factors.”
Moreover, it remains worth pointing out that no one personality type remains optimal over another. The big five are mere descriptions of the variations that persist across the personality spectrum. Also, it remains worth noting that, although the big five personality traits have been generally accepted, still, others have expanded the concept further. George Kelly, for instance, created his own personal construct theory based on different “idiographics”—or, “documenting each individual’s uniqueness.”
Jarrett writes: “Kelly proposed that we each see the world in the context of a unique set of dialectic constructs (such as whether people are kind or not) and that by uncovering these constructs, we learn how a person sees the world.” In other words, unlike Eysenck’s PEN personality model described earlier, Kelly’s personal construct theory of personality remains more holistic; it takes various dimensions of the individual into consideration—including the person’s subjective context.
As noted from the outset, beginning with the Greeks, humans have been attempting to quantify and categorize personality for centuries. Significant headway had been made by Hans Eysenck’s PEN model in the 1940s and later by other psychological researchers who developed the big five. What is more, George Kelly’s personal construct theory has also helped to shed light on the subject.
In the end, although progress has been made in attempting to understand human personalities, there still remains shadowy areas in our knowledge that have yet to be explored. The big five traits, for example, explain a lot, but the individual genetic, environmental, cultural, and psychological dimensions that converge on each individual to create “us” remain somewhat murky still. After all, it cannot be said that low forms of life have personalities in the way that humans possess them. There, indeed, appears to remain something unique about our species that has given rise to each of us, individually.
Bowdon, T. (2007). 50 psychology classics who we are, how we think, what we do: Insight and inspiration from 50 key books. London: Nicholas Brealey Pub.
Jarrett, C. (2011). 30-second psychology: The 50 most thought-provoking psychology theories, each explained in half a minute. Sydney: Murdoch Books.