What is the target?

Reconciling the differential perspective with the Piagetian perspective is a very difficult task. The Piagetian perspective admits the existence of interindividual differences but interprets them as noise masking the universal logical succession of structures, whereas the differential perspective views development as consisting of "vicarious processes." As a matter of historical fact, the main aim of the "procedural studies" carried out in Geneva was to introduce concrete microgenesis into the macrogenetic Piagetian model. [ABSTRACT FROM AUTHOR]