The poor performance of boys in relation to girls, particularly in reading skills, is a relatively new phenomenon. The recent debate has usefully highlighted the problem. But if it is to be solved, an explanation for boys’ underachievement must be found.

Two points may help to concentrate thinking. First, why did these sex differences in reading not exist in the past? Various surveys reporting on standardised reading scores show that, formerly, where sex differences did occur at the age of seven or eight, they usually disappeared by the age of 11. Today, significant differences between girls and boys are still dramatically apparent in English tests at the ages of 14, 16 and 18.

Second, these differences do not occur in other countries, such as Germany and Austria, even at the ages of seven or eight. One might imagine this is due to the greater regularity of their language or to differences within their culture. However, there is one English-speaking country that is very similar to England but where no sex differences in reading exist. That country is Scotland.

As late as 1992, when sex differences in England had become the norm, no sex differences in reading scores existed among Scottish eight-year-olds. Furthermore, a comparison of the results of Scottish and English children on the Edinburgh Reading Test showed that, compared to all English children, Scottish boys were reading at a level four months in advance. However, compared to English boys, their level was 10 months in advance.

A number of reasons have been put forward to explain boys’ poor achievement. With these reasons in mind, one might wonder whether boys mature more slowly in England than in Scotland, or whether there are differences between the two countries in boys’ brains, or the number of females involved with teaching reading at home or at school. Do Scottish teachers choose more appropriate books for boys to read, or are boys better-behaved in Scotland?

Before dealing with these questions, it is important to note there is one major difference in educational policy between the two countries. While 1960s child-centred methods of instruction have radically reshaped the teaching of reading in England, in Scotland methods have remained more traditional and phonics-based. It may be that code-based methods of reading instruction are more advantageous for boys than other methods.

Boys do mature at slower rates than girls. Australian research shows that young boys are eight months behind girls in their ability to remember some letters in a word. At the age of five, boys can remember on average only one letter in a word. Yet in England, boys of this age are expected to remember words such as “crocodile” or “slippers”.

In Scotland, where teaching focuses more on phonic-processing skills, boys are given the opportunity to process letters one at a time and to transfer visual information to auditory memory. Thus their low visual memory skills become relatively unimportant.

Boys and girls do appear to use different areas of the brain when reading. Areas predominantly in the left hemisphere are activated in boys, whereas areas in both hemispheres are activated in girls. Evidence suggests that England’s mixed methods, where pictures, word shape and word length (largely activating right-brain processes) are encouraged as reading strategies, put boys - who have “all their eggs in one basket” so to speak - more at risk of failing to use the appropriate left-hemisphere skills.

It is indeed possible that boys in England, where guessing and memorisation of whole words is more widespread, will be much less motivated to read than boys in Scotland. Word guessing brings limited rewards when guesses are based only on the one letter of a word that boys of a young age are capable of retaining in visual memory.

Another possible reason suggested for boys’ lack of motivation is that teachers choose inappropriate books for them. Book choice has been changing in Scotland, and whole-word eclectic reading schemes and “real books” are becoming as popular as they are in England. However, if it is still the case that boys in Scotland receive more direct instruction in phonological coding as well as, or before, being introduced to such books, it is likely that these books will not be quite so inappropriate or difficult for them to read.

Finally, if teachers in England fail at the start to provide boys with a logical and effective strategy for reading words, the frustration and boredom that result could lead to behaviour much worse than that displayed by Scottish boys. If boys do not succeed in learning to read, they may quickly discover that they can succeed in making a nuisance of themselves.

Dr Bonnie Macmillan is a research fellow at The Institute of Economic Affairs and the author of Why Schoolchildren Can’t Read (1997)