 "Zone of Proximal Development" (ZPD) is a term Vygotsky used to characterize an individual's mental development.He believed the task individuals can do on their own do not give a complete understanding of their mental development.He originally defined the ZPD as “the distance between the actual developmental level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance or in collaboration with more capable peers.” He cited a famous example to make his case.