As a pioneering psychologist in the merging studies of cognition and learning, Jean Piaget helped change the common assumption that as thinkers, children are merely less complex versions of adults. His twentieth century work built upon the classical roots of Socrates, and more recent work of Lev Vygotsky, Jerome Bruner, and others who believed learning to be a process facilitated, rather than caused, by teachers. At the forefront of constructivist assumptions are the notions that the most effective learning takes place when learners are active and motivated participants in the process.
While constructivism as a system has been criticized as being too subjective and difficult to manage, as with so many complex systems it has several components that stand out as applicable outside of the larger theory as a whole. The notions of assimilation and accommodation are two of my favorites. Assimilation occurs when a learner adds new information, basically layering it on top of the old. Accommodation occurs when a learner must change previously learned information before placement of new information is possible. Assimilation is like placing files in a file cabinet, while accommodation is like needing to add new folders, or rearrange existing ones. Because of this, learning is said to get more difficult as we age, with the tendency of older people to get what has been deemed, “hardening of the categories.”
Piaget and the constructivists also coined all kinds of terms, such as schema and equilibrium, not to mention those associated with the famed stages of development, such as the sensorimotor, concrete operational, and preoperational stages. Piaget’s ballyhooed notion of object permanence (the understanding that an object exists even when out of sight) has been extensively studied and debated.
As with seemingly all mind related theories, the popularity of constructivism has followed the pendulum of favorability. There are many specific aspects of constructivism, though, that should stand the test of time. Some additional good information can be found here. This, also is kind of cool.