266 LANGUAGE AND MENTAL DEVELOPMENT OF CHILDREN
we are beginning now to rid ourselves of the cruder of our former
beliefs. It used to be assumed, for example, that the sooner a teacher
began formal instruction in reading, writing, and arithmetic the
sooner the child would master them. But we know now that no child
is ready for formal instruction until (a) he has passed through the
period of aimless play to that of purposive play, in which the desire
to complete a self-imposed task has begun to function, and (4) he has
reached a certain-mental age as determined by individual intelligence
tests. It was thought, too, that children of junior school age were
incapable of reasoning, and had better, therefore, be employed in ,
acquiring mechanical skill and routine knowledge, in this way master-
ing tools and materials for rational use later. The performances of
junior children in intelligence tests demanding reasoning ability have
disproved our earlier theories in this direction. That there is an
optimum mental age for beginning certain kinds of instruction is
becoming clear, and the teacher who mistakingly anticipates it will
often find by experience that his error is irretrievable.
Thus, if we find, as we do, that to the child of eight a knife is a
thing you cut with, a chair a thing you sit on, and so on, it is clearly
futile to teach at this age any subject in which an appreciation of
logical definition is necessary. For the same reason, science as such,
the history of political and religious controversy, and much economic
geography are out of place in a junior (and often a senior) school
curriculum.
In the past fifteen years a great deal of systematic and close observa-
tional work has been done with a view to elucidating the stages of
mental growth, so far principally with infant children. The work of
Arnold Gesell, whose work on The Mental Growth of the Pre^schdol Child
appeared in 1925, has been followed by a number of similar studies,
among which Piaget's work in Geneva,1 Charlotte Biihler's work in
Vienna,2 and Dr Susan Isaacs's work at the Malting House School,
Cambridge,3 have been, perhaps, the most conspicuous.
The essence of the method employed by all these workers is to
observe children in significant life situations and make systematic
records of their behaviour. As a result, they are able to give us typical
pictures of children in different stages of growth behaving as they do
in everyday life, rather than as they may in an artificial test situation.
Since observation of this kind has been directed to infant behaviour
in various directions, we are now in a position to attempt charts
which will show the early stages of development in many important
directions—e.g., in sense activity, intelligence, bodily control, manipu-
lative ability, emotional poise, and social adaptability.
The test material that follows was devised by the author as a help
towards the elucidation of the many different forms which linguistic
development may take. It is hoped that it will also be of some help
to others anxious to understand in greater detail the general problem
with which we have been dealing in the present book.
1 Language and Thought of the Child (London, Kegan Paul, 1927).
9 From Birth to Maturity (London, Kegan Paul, 1935).
8 Intellectual Growth in Toung Children (London, Routledge, 1930).