Primary school pupils are better behaved within the classroom than in the 1970s, says a long-term study by educational psychologists.
The study credits better teaching and constant verbal encouragement as the reasons more pupils are paying attention to their work.
Educational psychologist Brian Apter says the improvement seems to have accelerated since the mid-1980s.
"Teachers are working incredibly hard now," says Mr Apter.
Rejecting the stereotypes of disrupted lessons and deteriorating discipline, Mr Apter says that the proportion of pupils who are "on task" during lessons has been steadily rising.
The findings, based on observations of more than 70 educational psychologists in 141 classrooms across the UK, found a "fairly steady upward trend" in terms of improving behaviour.
Mr Apter, district senior educational psychologist at Wolverhampton City Council, said that class size did not appear to be a significant factor in behaviour, or the number of other adult assistants in the classroom.
The key to this improvement was the teacher, said Mr Apter, and their constant verbal engagement with pupils - which he says has been described as the "motor mouth" approach.
"Primary teachers work incredibly hard now - it's something that educational psychologists often comment upon. They are engaging pupils around the classroom, they seem very much compelled to get results," says Mr Apter.
The energy of this teaching style and the focused approach of teachers, he says, means that pupils are less likely to drift off or misbehave during lessons.
Studies of classroom behaviour and attempts to gauge the amount of attention paid during lessons have been carried out since the early years of the 20th century.
But Mr Apter says it is very difficult to make reliable classroom comparisons with anything before the 1970s.
The current study claims that pupils are now better behaved than at any time since the 1970s, with the acceleration in the improvement beginning in the mid-1980s and continuing for the subsequent two decades.
The research - A Mass Observation Study of Student and Teacher Behaviour in British Primary Classrooms - was based on the proportion of pupils who were "on-task" (following the teacher's directions) or "off-task" (not following the teacher's directions).
"Primary school students have never before been observed to be so well behaved," concludes Mr Apter, in a study presented to a psychology conference in Glasgow.
While the overall trend shows better behaviour, Mr Apter also says that there is another contrasting message from teachers who anecdotally report that when there is misbehaviour it can be more extreme.
And at this year's annual conference of the Nasuwt teachers' union, delegates heard that bad behaviour from pupils is the biggest cause of stress for teachers.
The government appointed Sir Alan Steer to report on behaviour in school, which concluded earlier this year that "behaviour is generally good and is improving in our schools".
In terms of what influenced behaviour, Sir Alan identified the quality of teaching, clear and consistent rules, mutual respect and the support of parents. But he cautioned against assuming there were "simple solutions".Sir Alan has also emphasised that schools are not the places of danger in young people's lives - and that often they can be the safest havens in disrupted lives.