In the 1970s and 1980s, a new school of thought known as cognitive linguistics emerged as a reaction to generativist theory. Led by theorists such as Ronald Langacker and George Lakoff, linguists working within the realm of cognitive linguistics propose that language is an emergent property of basic, general-purpose cognitive processes, though cognitive linguistics has also been the subject of much criticism.^[26] In contrast to the generativist school of linguistics, cognitive linguistics is non-modularist and functionalist in character. Important developments in cognitive linguistics include cognitive grammar, frame semantics, and conceptual metaphor, all of which are based on the idea that form-function correspondences based on representations derived from embodied experience constitute the basic units of language.