ABSTRACT
We first discuss theoretical implications by way of two illustrations . The first relates to the debate on direct versus indirect perception and the second to the nature of representation of invisible objects. The value of research with very young subjects has long been recognized as contributing towards more general theories of mental representation. We conclude that there is still much gold to be won from this lode. The second theme concerns an increasing emphasis on process rather than product in perceptual development. Whereas earlier research sought to exhibit the competence of the young infant, the work described in the preceding chapters bears closely on the processes that underlie perceptual abilities and the limitations of these processes. Much recent research samples a single aspect of perceptual development and examines performance for different subjects at several ages. We suggest that a prime requirement for a fuller understanding of the processes involved is greater concentration on longitudinal studies over several aspects. There have been few attempts to develop more general models of perceptual development. A first step in the construction of such a model is the establishment of sequential relationships between different abilities. A second step in the validation of the model is to establish that treatment of a precursor ability has specific consequences for the later development of a target ability but not for another, i.e., for a control ability. There have been many cross-sectional analyses of separate capacities but few longitudinal studies whose aim is to
establish sequential dependencies between these capaCities. The third theme concerns individual differences , and particularly the use of habituation scores as predictors of concurrent and later cognitive status. It is now clear that habituation and familiarity measures are better predictors of later status than are standard infant psychometric tests. The kinds of processes underlying this continuity in development remain to be established.
