AS DOES much else in the universe, education moves in cycles. The 1960s and 1970s saw a swell of interest in teaching styles that were less authoritarian and hierarchical than the traditional watching of a teacher scribbling on a blackboard. Today, tastes have swung back, and it is fashionable to denigrate those alternatives as so much hippy nonsense.

But evidence trumps fashion—at least, it ought to. And a paper just published in Science by Louis Deslauriers and his colleagues at the University of British Columbia suggests that at least one of the newfangled styles is indeed superior to the traditional chalk-and-talk approach.

Dr Deslauriers's lab rats were a group of 850 undergraduate engineering students taking a compulsory physics course. The students were split into groups at the start of their course, and for the first 11 weeks all went to traditionally run lectures given by well-regarded and experienced teachers. In the 12th week, one of the groups was switched to a style of teaching known as deliberate practice, which inverts the traditional university model. Class time is spent on problem-solving, discussion and group work, while the absorption of facts and formulae is left for homework. Students were given reading assignments before classes. Once in the classroom they spent their time in small groups, discussing specific problems, with the teacher roaming between groups to offer advice and respond to questions.

At the end of the test week, Dr Deslauriers surveyed the students and gave them a voluntary test (sold as useful exam practice, and marked on a 12-point scale) to see how much they had learned in that week and what they thought of the new teaching method. The results were striking (see chart). The traditionally taught group's average score was 41%, compared with 74% for the experimental group—even though the experimental group did not manage to cover all the material it was supposed to, whereas the traditional group did.

According to Dr Deslauriers and his team, their result is the biggest performance boost ever documented in educational research, making the new teaching style more effective even than personal, one-to-one tuition—although measuring the effect immediately after the experiment, rather than waiting for end-of-term exam results (as other research often has), may have inflated the number somewhat. The results are especially impressive given that the deliberate-practice method was applied by teachers with little prior experience of using it, whereas the traditionally taught students had the benefit of a seasoned lecturer with a long record of good ratings from pupils.

One frequent criticism of these sorts of studies concerns something called the Hawthorne effect, an idea which emerged from post-war work on productivity. This is that change of any sort will boost people's performance simply because of the novelty value it offers. But the exact nature of the Hawthorne effect, and even whether it exists at all, is controversial. Moreover, if it is real, it would be unlikely to apply in this case, because it is supposed to occur mainly among people doing routine jobs, for whom any change in working practices is welcome. That is not a description of a typical undergraduate's life.

A more serious objection is that the study's participants may be an atypical group. The sort of people who study engineering may react better (or, indeed, worse) to the deliberate-practice method than, say, those reading fine art or history.

Still, Dr Deslauriers and his team are bullish about the wider implications of their work, which adds to the evidence that it may be possible to improve on the long-established chalk-and-talk method. And the students seemed to enjoy the experience, too. Attendance in the experimental group rose by 20% over the course of the week that deliberate practice was used, and three-quarters of its members said that they would have learned more had the entire course been taught in the same way. In this case, then, the educational hippies may have been right.