Why read this: This article gives B2 readers a clear way into a real scientific debate that they will meet again in biology, psychology and everyday news: how much of who we are is decided by our genes, and how much by our experiences. The Bayout court case offers a strong opening hook, and the rest of the piece guides students through twin studies, large DNA scans and life events without burying them in technical detail.
What to notice: Notice how the article keeps revising its own claim. It first suggests that one gene might cause violence, then says scientists no longer think that. It reports a 47% figure from twin studies, then a much smaller 9% to 18% figure from DNA scans. Watch for the linking words 'however', 'yet' and 'but', which signal each turn in the argument. Notice also the careful, hedged language: 'may', 'seems to', 'probably' and 'a little'. These are not weak choices; they show how scientists talk about evidence that is still incomplete.
Skills practised: Tracking a multi-step argument that does not fully agree with itself; reading numerical evidence in context (percentages and date ranges); inferring a writer's main idea from several paragraphs rather than a single line; using glossed phrases such as 'twin studies', 'genome-wide association studies' and 'foetal programming' to access a science register without getting lost in jargon.
"Are we born with our personality, or do we build it?"
"Scientists once hoped to find a few \"behaviour genes\". Today, twin studies, large DNA scans and stories of life events are all pointing to a much messier answer."
Tap any green word in the article to see its meaning.
In 2009, an Italian man named Abdelmalek Bayout faced nine years in prison for killing a man who had mocked him in the street. His lawyer made an unusual argument. He claimed that Bayout's DNA contained the , a tiny change linked to aggressive behaviour. Because of this, the lawyer said, his client could not be fully blamed. The court agreed and cut a year off the sentence. Today, however, scientists see the link between genes and behaviour as far more complicated than that.
For more than a century, people have asked a famous question: are we shaped by ? Are our personalities decided by the genes we are born with, or by the family, friends and events around us? An English scientist first studied this in twins back in 1875. By the 1920s, researchers were running that compared , who share 100% of their DNA, with , who share only 50%.
Modern psychologists describe personality through five broad traits, often called the : how open, careful, outgoing, kind and anxious a person tends to be. A large study in 2015 combined results from over 2,500 twin studies and concluded that around 47% of personality differences could be explained by genes. The other half, the researchers argued, must come from a person's environment. Other twin studies have reached similar numbers, usually somewhere between 40% and 50%.
Over the past 15 years, however, scientists have been able to read DNA in much greater detail. In , researchers compare millions of small differences in DNA across huge numbers of people, looking for tiny links to personality. The early work struggled to find clear results. We now know why: personality is shaped by thousands of these small differences, each adding only a tiny effect. Even when added together, they explain only 9% to 18% of personality differences, far below the 40% suggested by twin studies.
If genes matter less than once thought, perhaps experience matters more. Yet the picture is just as messy. Aysu Okbay, a researcher in genetics at Amsterdam UMC, says the true answer probably sits somewhere between the two estimates. Big life events such as winning the lottery or losing a leg seem to change personality far less than people imagine. Even marriage and becoming a parent only nudge it a little. The popular , the idea that hard times make us who we are, is not well supported by the evidence.
"Trauma doesn't make you who you are," says Brent Roberts, a psychology professor at the University of Illinois. Childhood difficulties can leave a lasting mark on adult personality, but stressful events later in life rarely do. Researchers are now asking about an even earlier influence: life inside the womb. Some studies suggest that high stress during pregnancy may slightly change a baby's later temperament, an idea called . The mechanism is unclear, but it seems that the environment can switch certain genes on and off.
The picture that emerges is not nature or nurture, but nature and nurture, woven tightly together. Personality, scientists now say, comes from many genes and many experiences, each pulling only a little. A does not force a person to behave in one fixed way. As Roberts puts it, humans are simply too complex to be reduced to a single gene or a single life event.
In 2009, an Italian man named Abdelmalek Bayout faced nine years in prison for killing a man who had mocked him in the street. His lawyer made an unusual argument. He claimed that Bayout's DNA contained the , a tiny change linked to aggressive behaviour. Because of this, the lawyer said, his client could not be fully blamed. The court agreed and cut a year off the sentence. Today, however, scientists see the link between genes and behaviour as far more complicated than that.
For more than a century, people have asked a famous question: are we shaped by ? Are our personalities decided by the genes we are born with, or by the family, friends and events around us? An English scientist first studied this in twins back in 1875. By the 1920s, researchers were running that compared , who share 100% of their DNA, with , who share only 50%.
Modern psychologists describe personality through five broad traits, often called the : how open, careful, outgoing, kind and anxious a person tends to be. A large study in 2015 combined results from over 2,500 twin studies and concluded that around 47% of personality differences could be explained by genes. The other half, the researchers argued, must come from a person's environment. Other twin studies have reached similar numbers, usually somewhere between 40% and 50%.
Over the past 15 years, however, scientists have been able to read DNA in much greater detail. In , researchers compare millions of small differences in DNA across huge numbers of people, looking for tiny links to personality. The early work struggled to find clear results. We now know why: personality is shaped by thousands of these small differences, each adding only a tiny effect. Even when added together, they explain only 9% to 18% of personality differences, far below the 40% suggested by twin studies.
If genes matter less than once thought, perhaps experience matters more. Yet the picture is just as messy. Aysu Okbay, a researcher in genetics at Amsterdam UMC, says the true answer probably sits somewhere between the two estimates. Big life events such as winning the lottery or losing a leg seem to change personality far less than people imagine. Even marriage and becoming a parent only nudge it a little. The popular , the idea that hard times make us who we are, is not well supported by the evidence.
"Trauma doesn't make you who you are," says Brent Roberts, a psychology professor at the University of Illinois. Childhood difficulties can leave a lasting mark on adult personality, but stressful events later in life rarely do. Researchers are now asking about an even earlier influence: life inside the womb. Some studies suggest that high stress during pregnancy may slightly change a baby's later temperament, an idea called . The mechanism is unclear, but it seems that the environment can switch certain genes on and off.
The picture that emerges is not nature or nurture, but nature and nurture, woven tightly together. Personality, scientists now say, comes from many genes and many experiences, each pulling only a little. A does not force a person to behave in one fixed way. As Roberts puts it, humans are simply too complex to be reduced to a single gene or a single life event.
Questions
Check your understanding
- 01
Why did Abdelmalek Bayout's lawyer mention his client's DNA in court?
- 02
What does the gap between the twin study figure of 47% and the genome-wide association study figure of 9% to 18% most likely suggest?
- 03
Which sentence best captures the article's main idea?
- 04
Evaluate the lawyer's use of the warrior gene argument in Bayout's trial. Based on what the article says later about genes and behaviour, was it a strong argument?
Suggested length: ~80 words
- 05
How does the article challenge the popular idea that traumatic experiences shape who we are?
Suggested length: ~80 words
Questions
Check your understanding
- 01
Why did Abdelmalek Bayout's lawyer mention his client's DNA in court?
- 02
What does the gap between the twin study figure of 47% and the genome-wide association study figure of 9% to 18% most likely suggest?
- 03
Which sentence best captures the article's main idea?
- 04
Evaluate the lawyer's use of the warrior gene argument in Bayout's trial. Based on what the article says later about genes and behaviour, was it a strong argument?
Suggested length: ~80 words
- 05
How does the article challenge the popular idea that traumatic experiences shape who we are?
Suggested length: ~80 words