Inheriting Personality Traits

When we study personality, we often come to questions of nature versus nurture: are we born with genetic traits that lead us to behave certain ways? Or is it our experience that makes us who we are? Today, it is generally accepted that both nature and nurture play an important role in the development of personality, but to what extent each affects us is still a point of major controversy.

Research on personality types has typically focused on differences between individuals who have reached adulthood, rather than attempting to trace the development of those differences. But recent studies done on children and adolescent personality types have yielded intriguing findings.

Temperament, Personality; Tomay-to, Tomah-to?

Although we can observe individual differences among young children – some newborns are relatively unfussy, others all but impossible to soothe – some argue that we’re not seeing a “personality,” but a “temperament.” However, there are also those who see these terms as virtually synonymous, owing to the fact that many traits of temperament are carried into adulthood, where they come to be a part of personality.

For example, adults who score high on extraversion were often children who would have tested high on “surgency,” a temperament trait associated with high activity levels, impulsivity, and engagement with one’s environment. Similarly, children who are characterized as “shy” or “not particularly social” typically score high in introversion as adults. This isn’t always the case – a physically energetic child may mature into a talkative adult, for instance – but there is often continuity between youthful temperament and adult tendencies.

But if temperament can be seen as the basis for personality, we must still wonder how temperament “evolves” over time. Is a maturing temperament shaped more by forces from within, or without?

Twin Studies

Nature vs. Nurture may still spark lively debates, but there is one thing everyone can agree on: human nature is complicated. In an effort to reduce a dizzying array of variables to manageable observations, researchers have at times turned to twin studies, analyzing both fraternal twins (who share 50% of their genes) and identical twins (who are 100% genetic matches).

One such study, conducted at Edinburgh University on more than 800 sets of twins, found that identical twins were twice as likely as fraternal twins to share personality traits. Other studies have produced similar results in favor of nature’s dominant role in personality development, leading some to believe the debate is over.

However, even if nature is to credit (or blame!) for our developing personalities, the precise mechanism of gene expression into personality traits eludes us. Despite initial optimism that scientists were uncovering the specific genes responsible for everything from alcoholism to antisocial behavior, more recent studies have put these findings in dispute. Personality may have a primarily genetic basis, but the discovery of, say, a “gene for introversion” is unlikely.

Let’s Call the Whole Thing Off?

It can be tempting to simply dismiss the debate as academic: those who study genetic influences on behavior would probably say that, if genes do influence behavior, it is only through an intricate process that we have only begun to understand. Moreover, even if nature is dominant, nurture still plays a significant role in personality development.

But there’s more at stake than simply bragging rights for the “nature” camp or the “nurture” camp. Society itself is an attempt at shaping the behavior of others – consider parenting, education, and the criminal justice system. Currently, we have the luxury of mystery; we know so little about how the forces that shape personality work, we are freed of the responsibility that would come if those answers were known.

As it is, we learn to tolerate and embrace our differences, accepting that which we cannot change – but what if we could change? Would we continue to accept? If a “cure” for a certain personality trait were made available – through gene therapy, for instance – would prospective parents want to use it on their children? On themselves?

Understanding Breeds Acceptance

Our current conception of personality, as an enigmatic accident, is one that strongly encourages a sense of “different, not better.” Most of us understand that some people are thinkers, while some are feelers; some are more outgoing, some are more reserved. And while there are biases – an extravert librarian or an introvert politician still surprises us – most of us feel that there is a place for everyone, and it’s a matter of finding the right fit for our personality.

Whether our differences are more the result of our genes or our upbringing, accepting these differences is more often beneficial than attempting to impose our preferences on others. History, after all, is filled with examples of the harm involved when square pegs have been hammered into round holes.