The myth that most brain development is over by the time children start school has been dispelled. We now know that striking changes in the parts of the brain that support executive functions - the ability to control our thoughts and emotions - continue into late adolescence and adulthood. And yet the early years provide the first opportunity to capitalise on young brains' receptivity and equip them for learning.
As a formal curriculum is extended to younger children, this is a matter of immediate concern. How should early learning activities be structured? Should we aim for content-specific targets, such as the achievement of a basic knowledge of sounds? Or should the focus be on more general skills, such as self-discipline and attention control?
Self-control is a key component of classroom adjustment, and extreme failures result in alarming exclusion rates later. However, as you will know if you spend time in a lively nursery, it is easy to doubt whether it is possible to train children's executive functions in a preschool setting - and whether it would actually assist early learning.
Adele Diamond of the University of British Columbia and her colleagues at Rutgers University in the US tested this, comparing the effects of early executive functions training and a programme fostering specific skills.
They capitalised on a low-income urban district's plans to improve provision for disadvantaged children. Preschool teachers and assistants were randomly assigned to build into their everyday classroom activities either a curriculum designed to develop executive functions (Tools of the Mind) or a more traditional literacy strategy.
The Tools of the Mind programme promotes executive functions such as inhibition, working memory and cognitive flexibility by supporting, training and challenging these skills in most classroom activities. For example, through "buddy reading", a child learns to listen and take turns by physically holding a visual reminder (a line-drawing of an ear) while another "reads" a picture book. Preschoolers are also encouraged to plan play using images, and to help one another by monitoring compliance with agreed rules and roles.
The literacy curriculum focused instead on teaching though a combination of reading, writing and listening.
It covered the same academic content as Tools, but children were not expected to learn how to regulate themselves.
When children were five (one or two years after beginning either programme), they were tested on tasks pioneered by Professor Diamond to tax all key components of cognitive control in infants, toddlers and preschoolers.
None of the children had encountered these tasks before. However, children in the Tools programme outperformed the others, especially on the measures requiring the co-ordination of multiple executive functions. For example, in the dots task, a heart or a flower appeared to the right or left of a computer screen. In the most demanding version of the task, preschoolers had to maintain a rule in working memory ("press the button on the same side as the shape") and shift to the more difficult and inhibition demanding rule ("press the button on the opposite side to the shape").
Critically, performance on these most challenging executive tasks was closely related to their performance on other general measures, such as a Get Ready to Read screening tool routinely used to check preschoolers' progress in early literacy skills in the United States. Here, the children who had done the Tools programme performed better.
The findings back up an earlier (but smaller) study led by Michael Posner of the University of Oregon. This study found signs of increased mature activity by the brain's pre-frontal circuits in children as young as four after training on a computer program that increasingly taxed their concentration, discrimination and predictive ability.
For instance, the preschoolers learnt to focus their attention on smaller differences between images on a screen, such as two versions of a cartoon snake.
Professor Diamond's research leaves many questions unanswered. No "before and after" measures of basic academic performance or of executive skills were taken. So we do not know whether Tools alone resulted in improved executive functions over and above predictable age changes. Nor was children's brain activity measured during the study. It is likely that the Tools programme produced measurable changes in prefrontal circuits. But, since the programme also focuses on social interaction between peers, it may also affect the circuits involved with the emotional aspects of control and motivation.
The study also could not establish whether children in the (intensive and well structured) literacy programme were better prepared for school than the others, even if their executive scores were poorer.
Finally, would executive skills training be especially beneficial to preschoolers at risk of later developing specific learning difficulties, such as dyslexia?
The findings strongly suggest that the policymakers should consider the development of executive skills as a vital element of early learning. The jury may still be out on whether one can be too young to be formally taught. However, it seems clear that one is never too young to learn how to learn
Dr Gaia Scerif is a lecturer and developmental cognitive neuroscientist at the University of Oxford
Tools of the Mind is a research-based early childhood programme from the US that promotes children's self-regulated learning. Teachers systematically support children's movement along a continuum from being regulated by others to becoming "masters of their own behaviour".
Children gain control of their social, emotional and cognitive behaviour by learning how to use a variety of mental tools. It is based on principles set out by the Russian thinkers Alexander Luria and Lev Vygotsky, who extended the idea of human beings as tool-making animals to include mental tools, such as lists or reminders that we might use to jog our memory.
Diamond, A., Barnett, W.S., Thomas, J., amp;amp; Munro, S. (2007) Preschool Program Improves Cognitive Control. Science, 318, 1387-88 (and supplemental online material).
Rueda, M.R., Rothbart, M.K., McCandliss, B.D., Saccomanno, L., amp;amp; Posner, M.I. (2005) Training, Maturation, and Genetic Influences on the Development of Executive Attention. Proceedings of the National Academy of Sciences, 102, 14931-36 (and http:www.teach-the-brain.orglearnattentionindex.htm).