TWENTY years ago, children in pre-school, kindergarten and even first and second grade spent much of their time playing: Building with blocks, drawing or creating imaginary worlds, in their own heads or with classmates. But, increasingly, these activities are being abandoned for the teacher-led, didactic instruction typically used in higher grades. In many schools, formal education now starts at age four or five. Without this early start, the thinking goes, children risk falling behind in crucial subjects such as reading and maths, and may never catch up.
The idea seems obvious: Starting sooner means learning more; the early bird catches the worm.
But a growing group of scientists, education researchers and educators say there is little evidence that this approach improves long-term achievement; in fact, it may have the opposite effect, potentially slowing emotional and cognitive development, causing stress and perhaps even souring children's desire to learn.
One expert I talked to recently, Dr Nancy Carlsson-Paige, a professor emerita of education at Lesley University in Cambridge, Massachusetts, describes this trend as a "profound misunderstanding of how children learn". She regularly tours schools and sees younger students floundering to comprehend instruction: "I've seen it many, many times in many, many classrooms - kids being told to sit at a table and just copy letters. They don't know what they're doing. It's heartbreaking."
The stakes in this debate are considerable. As the sceptics of teacher-led early learning see it, that kind of education will fail to produce people who can discover and innovate and will merely produce people who are likely to be passive consumers of information, followers rather than inventors. Which kind of citizen do we want for the 21st century?
In the United States, more academic early education has spread rapidly in the past decade. Programmes like No Child Left Behind and Race To The Top have contributed to more testing and more teacher-directed instruction.
Another reason: the Common Core State Standards, a detailed set of educational guidelines meant to ensure that students reach certain benchmarks between kindergarten and 12th grade. Currently, 43 states and the District of Columbia have adopted both the math and language standards.
The shift towards didactic approaches is an attempt to solve two pressing problems.
By many measures, US educational achievement lags behind that of other countries; at the same time, millions of American students, many of them poor and from minority backgrounds, remain far below national norms. Advocates say that starting formal education earlier will help close these dual gaps.
But these moves, while well-intentioned, are misguided. Several countries, including Finland and Estonia, do not start compulsory education until age seven. In the most recent comparison of national educational levels, the Programme for International Student Assessment, both states ranked significantly higher than the US in maths, science and reading.
Of course, these countries are smaller, less unequal and less diverse than the US. In such circumstances, education poses fewer challenges. It is unlikely that starting school at age seven would work in the US: Too many young children, disadvantaged or otherwise, would probably end up watching hours of television a day, not an activity that promotes future educational achievement. But the complexities of the task in the US do not erase a fundamental fact that overly structured classrooms do not benefit many young children.
Some research indicates that early instruction in reading and other areas may help some students, but these boosts appear to be temporary. A 2009 study by education researcher Sebastian Suggate, from Alanus University in Germany, looked at about 400,000 15-year-olds in more than 50 countries and found that early school entry provided no advantage. Another study by Dr Suggate, published in 2012, looked at a group of 83 students over several years and found that those who started at age five had lower reading comprehension than those who began learning later.
Other research has found that early didactic instruction might actually worsen academic performance. Psychology professor Rebecca Marcon, from the University of North Florida, studied 343 children who had attended a preschool class that was "academically oriented", one that encouraged "child-initiated" learning, or one in between. She looked at their performance several years later, in third and fourth grade, and found that, by the end of the fourth grade, those who had received more didactic instruction earned significantly lower grades than those who had been allowed more opportunities to learn through play. Children's progress "may have been slowed by overly academic pre-school experiences that introduced formalised learning experiences too early for most children's developmental status", Dr Marcon wrote.
Nevertheless, many educators want to curtail play during school. "Play is often perceived as immature behaviour that doesn't achieve anything," said Dr David Whitebread, a psychologist at Cambridge University who has studied the topic for decades. "But it's essential to their development. They need to learn to persevere, to control attention, to control emotions. Kids learn these things through playing." Over the past 20 years, scientists have come to understand much more about how children learn. Dr Jay Giedd, a neuroscientist at the University of California, San Diego, has spent his career studying how the human brain develops from birth through adolescence; he says most children younger than seven or eight are better suited for active exploration than didactic explanation. "The trouble with over-structuring is that it discourages exploration," he said.
Reading, in particular, cannot be rushed. It has been around for only about 6,000 years, so the ability to transform marks on paper into complex meaning is not pre-wired into the brain. It does not develop "naturally", as do other complex skills such as walking; it can be fostered but not forced. Too often that's what schools are trying to do now. This is not to suggest that we should not increase access to pre-school, and improve early education for disadvantaged children. But the early education that children get - whatever their socioeconomic background - must truly help their development.
NEW YORK TIMES