Foreword<br > More and more the importance of child development is being<br >recognized in education. The processes of learning， from the early<br >motor experimentation of the child to the establishment of at><br >stract concepts， is being soel~ as oleo coI]tintlOtlS prog] ession. <br >Pi aget ha.q shown that there are step-like processes in this devel-<br >opmental course where the child shifts over from one method of<br >ln Ocessing" learnin:~ data to a more complex method. These obser-<br >>lions of Piaget have given new impetus to the significance of<br >child develot)ment and have helped to demonstrate how the initial<br >learnings of the infant and the complex verbal-symbolic manipu-<br >lations of the older child in the classroom can all be seen as "one<br >piece of cloth." The intactness and completeness of the dewqop-<br >mental course of the child thus become as impe， rtant to the teacher<br >as his intelligence level or cultural background.<br > Nowhere is Elm course of development more important than in<br >the education of the slow learner or the child with a learning dis-<br > ability. One of the characteristics of such children is a breakdown<br > in development， usually at one of Piaget s stel)-like processes. As<br > a result the child s method of processing learning data remains<br > i}rimitive and education tends to become a procedure of aborting<br > this primitive process to serve the ends of tasks which require<br > more complex procedures. Since educational presentations assume<br > more advanced processing， the child must struggle to meet class-<br > room demands with his more limited procedures while he be-<br > comes mol e and more confused alld the teacher becomes more<br > and more frustrated with each passing day. The solution would<br > seem tt} be to restore the courses of development in the child in<br > order to give him the more complex methods of processing data<br > required by the school curriculum.<br > Various workers in the fieht of education of the slow learner<br > have concentrated their interest on different levels oi the devel-<br > opmental progression. Thus， the group at the Glen tlavcn<br > Achievement Center has been interested in the early， percct)iual-<br >