Sir Ken Robinson, chair of the UK Government's report on creativity, education and the economy, described research which showed that young people lost their ability to think in "divergent or non-linear ways" - a key component of creativity.
Of 1,600 children aged 3-5 who were tested, 98 per cent showed they could think in divergent ways. By the time they were aged 8-10, 32 per cent could think divergently. When the same test was applied to 13-15s, only 10 per cent could think in this way. And when the test was used with 200,000 25-year-olds, only 2 per cent could think divergently.
Sir Ken commented: "The trouble is that nothing rewards people for thinking off-piste. Education is driven by the idea of one answer and this idea of divergent thinking becomes stifled."
He described creativity as the "genetic code" of education and said it was essential for the new economic circumstances of the 21st century.
Sir Ken, who lives in California but was formerly professor of education at Warwick University, said: "Every education system is being reformed just now and there are two reasons why: economic - people are anxious to develop a system of education to equip them to live their lives in the new economic circumstances of the 21st century; and cultural - every community is concerned about their cultural identity."
He also called for an end to the hierarchy of subjects within the curriculum, with maths and language at the top and the rest in descending order.
"Along the way in our education system, we have become preoccupied with a particular form of education - the able and the less able," Sir Ken said.
Schools also had to move away from a utility model where subjects were valued more if they were seen as likely to provide jobs.
The conference, on "Confident Creativity", heard from Michael Morpurgo, the children's laureate, who called for every primary teacher in training to take a course in children's literature.
"Creativity rarely flourishes under the cosh," Mr Morpurgo said. "We need to unchain the teachers and give them room to be creative themselves. Let all primary schools have the last half-hour of the day for story-time, reading or creative writing.
"Tony Blair recently proposed a minimum of two-and-a-half hours for PE every week, but let's also have the same time in exercising our creative imagination and stop the child from becoming a narrow-minded myopic bigot."
Margo Williamson, principal education officer with Learning and Teaching Scotland, told the conference there was a will now and there would be a will in the future for more creative learning.
"When I look south and look at the literacy hour and the new literacy strategy, it does look as if there is initiative overload," Ms Williamson said. "In Scotland, I think there is more autonomy for teachers instead of the same template for every teacher."
Ms Williamson said the review of the curriculum had shown that everyone knew where they wanted to be but were still working on how to get there.
During the final panel sessions, Sue Ellis, a senior lecturer in primary education at Strathclyde University, warned that better test results do not equate with a higher quality of education.
"If a higher testing scheme is introduced, results rise for the first four years and then tend to flatten after year five because pupils and teachers become more test literate," she said.
Ian Smith, founder of Learning Unlimited, called for more passion, love, confidence, enthusiasm, risk and space, and less testing, inspection, measurement, fear and boredom in the classroom.
Paul Munden, director of the National Association of Writers in Education, called on teachers to invite more artists into schools to inspire children.