The principle of linguistic relativity holds that the structure of a language affects the ways in which its speakers are able to conceptualize their world, i.e. their world view. Popularly known as the Sapir–Whorf hypothesis, or Whorfianism, the principle is generally understood as having two different versions: (i) the strong version that language determines thought and that linguistic categories limit and determine cognitive categories and (ii) the weak version that linguistic categories and usage influence thought and certain kinds of non-linguistic behavior.
The idea was first clearly expressed by 19th century thinkers, such as Wilhelm von Humboldt who saw language as the expression of the spirit of a nation. The early 20th century school of American Anthropology headed by Franz Boas and Edward Sapir also embraced the idea. Sapir’s student Benjamin Lee Whorf came to be seen as the primary proponent as a result of his published observations of how he perceived linguistic differences to have consequences in human cognition and behavior. Harry Hoijer, one of Sapir’s students, introduced the term “Sapir–Whorf hypothesis”, albeit infelicitous due to Sapir’s non-involvement with the idea and the term’s misleading use of hypothesis in a colloquial (i.e. non-scientific) sense. Whorf’s ideas were widely criticized, and Roger Brown and Eric Lenneberg decided to put them to the test. They reformulated Whorf’s principle of linguistic relativity as a testable hypothesis and conducted experiments designed to find out whether color perception varies between speakers of languages that classified colors differently. As the study of the universal nature of human language and cognition came in to focus in the 1960s the idea of linguistic relativity fell out of favor. A 1969 study by Brent Berlin and Paul Kay showed that color terminology is subject to universal semantic constraints, and the Sapir–Whorf hypothesis was seen as completely discredited.
From the late 1980s a new school of linguistic relativity scholars have examined the effects of differences in linguistic categorization on cognition, finding broad support for weak versions of the hypothesis in experimental contexts. Effects of linguistic relativity have been shown particularly in the domain of spatial cognition and in the social use of language, but also in the field of color perception. Recent studies have shown that color perception is particularly prone to linguistic relativity effects when processed in the left brain hemisphere, suggesting that this brain half relies more on language than the right one. Currently a balanced view of linguistic relativity is espoused by most linguists holding that language influences certain kinds of cognitive processes in non-trivial ways but that other processes are better seen as subject to universal factors. Current research is focused on exploring the ways in which language influences thought and determining to what extent. The principle of linguistic relativity and the relation between language and thought has also received attention in varying academic fields from philosophy to psychology and anthropology, and it has also inspired and colored works of fiction and the invention of constructed languages.