"Play is often talked about as if it were a relief from serious learning. But for children play is serious learning. Play is really the work of childhood."
The Swiss developmental psychologist Jean Piaget postulated four stages of children's cognitive development, the first of which, covering the ages from 0 to 2, need not concern us here.
In the preoperational stage, from about age 2 to 7, children cannot yet use logical thinking. In the concrete operational stage, from ages 7 to 12, children can think logically, but only with practical aids. In the formal operational stage, from age 12 upwards, children develop abstract thought and can think logically in their mind.
How does this relate to chess?
Chess is, at one level, a game of complex abstract reasoning. In particular it requires a particular type of thinking. We have to decide which moves we are going to consider, and decide, in each case, what we think is going to happen next. We then assess the consequences and make our decisions.
Piaget's theory would suggest that, up to the age of 7, children might be able to learn the names of the pieces and some of the moves, but would not be able to play a complete game. From 7 to 12, they would be able to play a legal game, but not a good game. Only from age 12 upwards would they start to develop the cognitive skills that would enable them to play well.
We now know, that, in certain circumstances, children can exceed Piaget's expectations by a very long way, in chess as well as in other domains. We know that some children can play a good game by the age of 7 and can approach master strength by the age of 12. But these are the exceptions, and require a very high degree of parental support and encouragement. In the vast majority of cases, Piaget is still valid.
Bear in mind, too, the long-standing research being carried out by Michael Shayer and his team at London University. In January 2006 they reported that 11- and 12-year-old children are "now on average between two and three years behind where they were 15 years ago", in terms of cognitive and conceptual development. My observation of chess players in primary schools during that period bears out their findings.
On the other hand, younger children are more attracted to board games, and, in general, better disposed to trying something new, than older children. So perhaps we should be looking at ways of approaching chess for young children which take Piaget's theories and the research of Shayer's team into account, and perhaps uses chess as a way of advancing children's cognitive development.
I would ask all parents and teachers to consider these points before deciding when and how to teach their children chess.