Piaget first observed and described the problems which young
infants have in understanding the nature of objects forty years ago.
Both his description and his analysis of the development of the
object concept are still widely supported today. This thesis,
while accepting the Piagetian description of the behaviours
involved, suggests that Piaget's account of the underlying
cognitive processes is no longer tenable. Alternative theories of
object concept development which have been put forward in recent
years are also examined and rejected. An identity theory of
object concept development is proposed and a series of six
interlinked experiments presented in an attempt to provide support
for this theory. On the basis of these and the many other
experiments reported in the literature, it is suggested that an
identity theory alone can adequately cover the variety of
appropriate and inappropriate object-related behaviours seen in the
first two years of life