Developing abstract thinking

Abstract thinking is a sign of maturity. Children do not develop it until they reach a certain age. However, that age is determined by what they are expected to do. Across the board, child development is predicated on what is expected of the child. In western Europe and North America, chidren do not learn the balance required to stand up in a boat and spear a fish until they are about 13 years old, however in the Amazon jungle, where children are encouraged to undertake this activity, it is rare that a child hasn't developed this ability by the age of 7. Similarly, American research found that children do not develop the ability to count in bases other than base 10 until they are 11 years old, and in doing so ignored the millions of people who learnt to count in bases 12 and 20 at the age of 7, simply because there were 12 pennies in a shilling and 20 shillings in a pound. The British monetary system required children to develop this ability earlier, so children developed it earlier.
So if children do activities that require them to undertake abstract thinking, then their ability to think abstractly will develop sooner.
One good way to promote this development is for them to play board games. Board games take real life and make it abstract. Simple games like "Snakes and Ladders" are ideal for teaching a child to count up to 100, to recognise the number of dots on a die, and so count up to 6 in a flash, and how to add numbers up to 6 + 6 = 12. All this should be accomplished in an unthreatening environment. There are no real ladders or real snakes involved, but the concept is there in abstract form, and this analogue develops abstract thinking. As a child gets older, then more complex board games, games like Monopoly and Risk, where tokens represent armies, and a map represents the world, should be played. These help develop abstract thinking. The use of puppets, as analogues for people, as we do in Puppet Maths, encourages abstract thinking by children, as the things that are possible in the immaginary world we create do not happen in the real world, but conceiveably could do.