British schoolgirl Lydia Sebastian joined the 1 per cent of those who have sat the exam who have obtained the highest mark of 162, putting her in the top 99.9th percentile of the population.
Lydia, from Essex, described the fiendishly difficult intelligence test as “easy”, according to Cascade news agency. She completed the 150-question Cattell III B paper, which primarily measures verbal reasoning ability, during her school holidays.
“At first, I was really nervous but once I started, it was much easier than I expected it to be and then I relaxed,” she said. “I gave it my best shot.”
Her father, Arun Sebastian, a radiologist at Colchester general hospital, said his daughter had spent an entire year talking about the test and had researched IQ test websites herself. “When I heard she had the maximum possible mark, I was overwhelmed, and so was my wife,” he said.
Lydia, who is about to start year eight at Colchester County High school for girls, has read all seven Harry Potter books three times and played the violin since aged four.
An only child to Mr Sebastian and Erika Kottiath, an associate director at Barclays Bank, she started talking at just six months.
“At the time, I was a trainee doctor and my wife was studying chemistry and I was away at the weekends,” said her 43-year-old father. “She used to say a few words to me on the phone.
“She also had an early interest in reading. When she was a few years old she was reading books that were for children several years older than her.
“We really have done nothing special with her.”
Lydia, whose favourite subjects include maths and physics, is now applying to join the Mensa society. Her parents, both originally from Kerala in southern India, say she voluntarily does homework until 8.30pm or 9pm.
“We’ve got a fairly laid-back view [about education],” added Mr Sebastian. “If a child is pushed to do something that’s not designed for their age then, personally, I’d feel they they’d be missing out on other things.”