How where you grow up affects your personality

Would you be a different person if you had grown up somewhere else? A growing body of research is helping to answer this age-old nature verses nurture question and what it means for your identity.

It was a hot afternoon in the little village near Kolkata, India, and the adults were asleep. My cousin and I were sitting on the floor munching on puffed rice with mustard oil when she turned to me and asked: "Is it true that people in Sweden eat cows and pigs?" I, just about 10 years old at the time, felt ashamed as I nodded. "So do they eat dogs and cats too?" she probed. It was a perfectly logical question. If you can eat one four-legged mammal, why not another? 

Having grown up in Sweden, albeit with an Indian mother, it wasn't something I had thought about before – vegetarianism was rare at the time, especially in Europe, and Swedish kids were accustomed to seeing cows as a source of food. My cousin, on the other hand, was a passionate animal lover with a habit of rescuing creatures she perceived to be in danger. She didn't eat meat.

My visits to India were full of such moments, which made me realise just how much culture shapes the way we think, feel and behave. If I had grown up in India, would I have had a different set of morals? A different sense of humour? Different dreams, hobbies and aspirations? Would I still have been me?

These are questions that scientists and philosophers have been grappling with for centuries, and now a new field of study – cross-cultural psychology – is beginning to investigate possible answers.

Nature vs nurture

In one sense, every human being's DNA is unique and its fundamental structure (in big-picture terms) does not change depending on where we go.

But DNA alone does not make us who we are, says Ziada Ayorech, a psychiatric geneticist at the University of Oslo in Norway. Born in Uganda, Ayorech moved to Canada when she was three, spent most of her life in the UK, and then moved to Norway a couple of years ago. "When I think about all the places I've lived and all the ways they have influenced my perspective, I intuitively imagine there's no way that that couldn't have made a difference," says Ayorech.

To explore this, scientists typically use studies comparing identical twins, who share almost identical DNA, to non-identical twins, who share, on average, half of their genome. This way, if identical twins are more or less likely to share a trait than non-identical twins, it suggests that that trait is more governed by genetics than environment.

In one large 2015 analysis of nearly 50 years of studies about 17,000 different traits in 14 million twins all over the world – exploring education and political beliefs to psychiatric conditions – scientists concluded that genetics accounts for, on average, just 50% of differences.

"It's that combination of nature and nurture that makes us who we are and contributes to our beliefs and our cultures," says Ayorech. "And so we couldn't have that same combination in another place."

The environment shapes some traits more than others, of course. Research shows that IQ is on average over 50% heritable, with the caveat that genetics plays a larger role later in life than it does in childhood. While personality traits are roughly 40% heritable and therefore more influenced by the environment. (This doesn't mean 40% of one person's extroversion is down to their genes, but rather that 40% of the differences in extroversion among a population as a whole can be explained by genetics.)

Although Ayorech is quite extroverted, she says Norway caters less to the types of outgoing expressions she is familiar with. For instance, one is less likely to break into a spontaneous conversation with a stranger on the streets of Oslo. This has changed her, she says.

"If you compare the version of me living here in Norway to the version of me that was living in the UK, it would be fair to say I'm less extroverted now," says Ayorech. But given her genetic makeup, she's unlikely to ever completely lose her outgoingness. She continues to subconsciously gravitate towards activities that encourage more spontaneous interactions, Ayorech says. "We tend to seek out environments that are in line with our genetic traits."

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In turn, this combination shapes our brains over time, allowing us to grow into ourselves. Neural pathways form and solidify as we integrate experiences, according to Ching-Yu Huang, a cross-cultural psychologist at National Taiwan University. She argues that culture is an "absolutely crucial part" of who we become.

"You would have been a different person if you'd grown up in Taiwan," she tells me, confidently. "The brain you have right now would be very different if you were born and had grown up in Taiwan, even if you have the same DNA." 

'When in Rome': Cross-cultural psychology

Vivian Vignoles, a cross-cultural psychologist at the University of Sussex, agrees. "I think people tend to get overexcited about the genetic side of it," he says. "Whatever genes you've got, you need a certain environment to bring them out."

While the basic idea that culture shapes how people see themselves is now well supported in psychology, it did come as a surprise to some psychologists in the mid-20th Century, Vignoles says. Scientists had long assumed that human psychology was universal and that study results about human behaviour conducted in the US and Europe would hold true across the world. But by studying and comparing psychology from elsewhere, Vignoles and others have found that this isn't the case. 

For instance, experiments suggest that people in the West tend to be more individualistic and see themselves more in terms of their personal traits, such as being funny, smart or kind, compared to people in Japan, who tend to be more collectivistic and likely to define themselves in terms of their social roles, such as being a father or a student.

In a study comparing people's brain scans, Westerners had the part of their brain responsible for self-awareness light up when thinking about themselves, whereas Chinese participants had that part light up when thinking about their mothers, too.

In similar tests, Huang and her colleagues looked at whether children of ethnically Chinese immigrants in England (who had come to the country from different parts of the People’s Republic of China, Hong Kong, Taiwan, Vietnam and Malaysia) viewed authority differently from non-immigrant English children and from Taiwanese children who had lived their whole lives in Taiwan. All children were equally likely to obey their parents across all three groups, but Taiwanese children were more likely to obey them even when they were initially reluctant, compared to Chinese immigrants raised in England.

Huang argues this is likely down to Taiwanese and Chinese culture valuing compliance and respect for parents, while the children whose families had emigrated to England were likely influenced by the culture in the UK to become more individualistic.

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A 2022 study comparing personality trait tests across 22 countries found that people living in a cluster of countries with cultures that place strong emphasis on self-discipline – such as Albania, India, Germany, France, Hong Kong and China – scored higher on measures of dutifulness and organisation. Countries with more egalitarian, flexible, and individualistic cultures – such as Canada, New Zealand, South Africa, Australia, the UK, Ireland, Norway, Philippines – demonstrated higher levels of agreeableness and openness to experience instead.

Researchers have also recently identified that Western cultures are more likely to be monumentalist, viewing the self as a stable and unchanging thing, like a monument, says Vignoles. Flexible cultures, common in East Asian countries, on the other hand, view the self as more malleable.

Another cultural difference is the extent to which people notice context. One study asked participants to describe a series of underwater scenes, and found that Western study participants focused more on individual objects, whereas Japanese participants emphasised the wider context, such as the colour of the surrounding water or how the different objects related to one another.

"There is some evidence that in Western cultures, particularly North American culture, people are more likely to attribute that behaviour to the person's characteristics rather than to the situation," says Vignoles. In a dentist's waiting room, Vignoles says, a Westerner is more likely to interpret a person who looks anxious as anxious overall, rather than just someone who is anxious about getting their teeth pulled in that context.

These results are always to be taken with a grain of salt, though, says Vignoles, as it is extremely difficult to disentangle behaviour, personality, culture and many other influences that come into play in this realm – and there is still so much more research to be done in the field.

For instance, a growing body of studies suggests that the east-west binary view of individualism versus collectivism is "far too simplistic", says Vignoles, and that the collectivism surfacing in many of these tests is probably more a feature of economic development than of culture. What's more, measurements of individualism in a country may miss important variations between specific groups or individuals in that nation. And a lot of studies in this area are based on self-reported responses from people, which aren't always accurate, rather than objective standardised tests.

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Philosophy's take on the conundrum

Perhaps the question of whether we'd be the same person in a different culture is ultimately a philosophical one – and one that interrogates the concept of self.

An online survey in 2020 of English-speaking philosophers revealed that 19% supported the view that each individual is a specific animal, resulting from a specific sperm and egg, and that it is not one's thoughts, feelings, or memories that make them who they are. "In this view, even if your memories were wiped, you'd still be the same person," explains Philip Goff, a philosopher at Durham University.

Similarly, about 14% supported theories suggesting the self isn't biological but rather encapsulated in something like a soul, and that that is what makes us who we are, no matter where we've grown up. In fact, studies show that many people believe they have a "true self" that is fundamentally morally good, and that this shouldn't change depending on where they are.

But other philosophers hold that one's surroundings also shape one's core identity – a theory dubbed social constructivism.

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Politics, in fact, seems to play a role too. In one experiment, researchers asked people with different political views to evaluate the morality of a Christian man who was attracted to other men. People who identified as liberals thought the man was acting according to his true self, while people who identified as conservatives believed instead he was going against his true, Christian self.

Goff himself believes that there is some sort of "fundamental unity" of cells and particles – and that consciousness is baked into this hardware – that makes us who we are, no matter where we grow up. But this likely changes over time as we grow and mature.

"These are just human concepts of what a 'person' or 'I' are," says Goff. There is likely no clear-cut answer, he says, on whether "that person in a very different circumstance would be me or not".

For people who have grown up in more than one culture, the feeling that humans are largely a product of their social environment is hard to shake. While it's difficult to know exactly who I would have been if I had spent my whole life in that village on the outskirts of Kolkata, I'm pretty sure there would be signs.

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