What makes a reader a reader? Do they have a genetic disposition for turning pages? Or did they become a bookworm because they grew up in a household full of bibliophiles?

For many, the answer to either question serves as a point for one of the sides in the longstanding examination of nature versus nurture. The back-and-forth has informed scientific studies, fueled academic debates and caused just about everyone at some point to wonder if their traits are hereditary byproducts or environmental effects.

Increasingly, those who study the field point toward genetics and experience as determining factors of our behavior, personalities and talent. Nature and nurture work together, as current thinking dictates.

A Back-and-Forth That Has Evolved

The first use of the terms “nature” and “nurture” dates back to the 19th century, as scientists studying the stages of human development psychology needed a shorthand to describe the influence of genetics and environment. In short, “nature” represents the theory that we behave according to genetic predispositions, while “nurture” means we act and think in accordance with how we are raised.

For centuries, the finer points of a person’s essence boiled down to an either-or argument. Those who espouse nature contend that genetics alone define not just a person’s eye color but also their sexuality and ability to play piano. Nurture advocates, on the other hand, didn’t refute the role of genetics but instead believed it ultimately mattered little because of the environment that shaped people.

While science has shown that genetics indeed form inborn abilities and traits, contemporary studies also support the defining role of environment, with factors such as parenting, geography and exposure to stressful situations helping to shape those genetic tendencies. With nurture influencing nature, and nature similarly swaying nurture, you could say a truce was reached in the argument. Both sides play a key role.

But despite wide acceptance of the shared role, the back-and-forth hasn’t ended. Instead, ardent supporters of either side now argue about the predominance of either nature or nurture. In other words, it’s a battle over proportion, a pointed nature versus nurture.

Environment Can Affect Genetic Traits

With researchers and academics drilling down into the finer points of nature and nurture, interesting findings and theories emerge. Consider psychologist Robert Plomin’s belief that genes account for only about half of what creates differences between people. The other half, according to Plomin, who is also a professor at King’s College in London, happens purely because of random experiences. The family that raises you and the friends you have influence your traits and personality far less than believed, Plomin claims. Once people accept that randomness, we’ll be free of the anxiety of believing we can harm one another through our actions.

Meanwhile, genetics researchers are reviewing how our daily lives can influence our inherent traits. While DNA is largely immutable, epigenetics influences how a person’s genome can be turned on or off, the researchers found. Exercise, sleep, stress, aging, diet, trauma and illness can create these epigenetic differences that affect DNA. With this in mind, the researchers are trying to deliberately alter gene expression with the hope of finding preventive medicine or treatments for diseases such as diabetes that have a strong genetic component.

The questions of nature and nurture have led researchers to study the stages of human development psychology in twins and triplets, who share not only the same genes but usually the same environment. Tim Spector, who is also a King’s College London professor, found that identical twins who shared the same parents and experiences while growing up nonetheless became different people. Even identical sisters who were treated as the same person by their parents forged different paths as adults. Here, Spector believes epigenetic differences triggered by health, diet, drugs and other factors can change one twin or triplet’s behavior and lead to consequential differences.

The story of identical triplets who were separated at birth and later reunited shows how the case can be made that nature and nurture each play defining roles in the paths that people take. The triplets shared genetic and some environmental similarities but ended up being different people, although that hereditary bond was always there.

A Common Ground Found in Reading

The middle ground that nature and nurture has reached brings us back to reading. As noted by a professor of genetics and a professor of cognitive development in a recent shared byline in The Conversation, reading is a cultural invention and not a skill that was incorporated into natural selection. Yet, the design for building a human circuitry that helps people read is somehow encoded in our genes.

At a basic level, children who have strong reading abilities want to read more, while children with lower reading abilities choose to read less, the professors say. Nurture, at this point, can make all the world of difference in informing nature. With parents and teachers who can help overcome any genetic predisposition — through training tips and encouragement — children who struggle to read can become better readers and actually enjoy it.