Change occurs through the introduction of new technologies and the continuous modification of existing technologies. Inducement mechanisms are diverse, responding to both supply (e.g., discoveries via scientific research, applied R&D) and demand (e.g., market or social demands such as environmental regulation) factors.
Moore's Law of increasing complexity of integrated circuits is illustrated for dynamic random access memories (DRAMs). Memory size (bits per DRAM) of new DRAM generations introduced doubles every 18 months, and average memory size sold doubles every 21 months. This is in agreement with a trend first suggested by Gordon E. Moore in 1965. Moore's "Law" is a classic case of a self-fulfilling prophecy. Because of widely shared visions of where the industry has to go - for example, in the form of future technology "roadmaps" and vigorous R&D efforts to realize these visions - Moore's "Law" has now held now for over 30 years through powerful DRAM generations. How long this trend can continue is uncertain in view of given the ultimate physical and economic barriers as well as the emergence of new technological alternatives.