Constructivism is an epistemological perspective based on the assertion that humans actively create the realities to which they respond (Mahoney, 1991;Neimeyer, 1993). Contemporary constructivist thought has its roots in a philosophical and psychological tradition that draws attention to the active role of the human mind in organizing and creating meaning-in literally inventing rather than discovering reality. The philosophical origins of constructivism include Vico's (1 725/1948) New Science and concept of "imaginative universals," Kant's ( 1791/1969) analysis of the limits of derived knowledge, and Vaihinger's (191 1/1924) neo-Kantian philosophy of "as if' (see Mahoney, 1988, for a detailed review), whereas formative contributions to constructivist thinking in psychology include Piaget's ( 1926) genetic epistemology, Bartlett's ( 1932) constructivist analysis of human memory, Hayek's (1952) treatise on the constructive nature of the human nervous system, Kelly's (1955) psychology of personal constructs, and Weimer's (1977) motor metatheory of mind.Building on these early philosophical and psychological foundations, constructivist theories have come to play an increasingly significant 69