In personality psychology, the lexical hypothesis[1] (also known as the fundamental lexical hypothesis,[2] lexical approach,[3] or sedimentation hypothesis[4]) generally includes two postulates:
1. Those personality characteristics that are important to a group of people will eventually become a part of that group's language.[5]
and that therefore:
2. More important personality characteristics are more likely to be encoded into language as a single word.[6][7][8]
With origins during the late 19th century, use of the lexical hypothesis began to flourish in English and German psychology during the early 20th century.[4] The lexical hypothesis is a major basis of the study of the Big Five personality traits,[9] the HEXACO model of personality structure[10] and the 16PF Questionnaire and has been used to study the structure of personality traits in a number of cultural and linguistic settings.[11]
Sir Francis Galton was one of the first scientists to apply the lexical hypothesis to the study of personality,[4] stating:
I tried to gain an idea of the number of the more conspicuous aspects of the character by counting in an appropriate dictionary the words used to express them... I examined many pages of its index here and there as samples of the whole, and estimated that it contained fully one thousand words expressive of character, each of which has a separate shade of meaning, while each shares a large part of its meaning with some of the rest.[12]: 181
— Francis Galton, Measurement of Character, 1884
Despite Galton's early ventures into the lexical study of personality, more than two decades passed before English-language scholars continued his work. A 1910 study by George E. Partridge listed approximately 750 English adjectives used to describe mental states,[13] while a 1926 study of Webster's New International Dictionary by M. L. Perkins provided an estimate of 3,000 such terms.[14] These early explorations and estimates were not limited to the English-speaking world, with philosopher and psychologist Ludwig Klages stating in 1929 that the German language contains approximately 4,000 words to describe inner states.[15]
Nearly half a century after Galton first investigated the lexical hypothesis, Franziska Baumgarten published the first psycholexical classification of personality-descriptive terms. Using dictionaries and characterology publications, Baumgarten identified 1,093 separate terms in the German language used for the description of personality and mental states.[16] Although this number is similar in size to the German and English estimates offered by earlier researchers, Gordon Allport and Henry S. Odbert revealed this to be a severe underestimate in a 1936 study. Similar to the earlier work of M. L. Perkins, they used Webster's New International Dictionary as their source. From this list of approximately 400,000 words, Allport and Odbert identified 17,953 unique terms used to describe personality or behavior.[16]
This is one of the most influential psycholexical studies in the history of trait psychology.[4] Not only was it the longest, most exhaustive list of personality-descriptive words at the time,[4] it was also one of the earliest attempts at classifying English-language terms with the use of psychological principles. Using their list of nearly 18,000 terms, Allport and Odbert separated these into four categories or "columns":[16]
Allport and Odbert did not present these four columns as representing orthogonal concepts. Many of their nearly 18,000 terms could have been classified differently or put into multiple categories, particularly those in Columns I and II. Although the authors attempted to remedy this with the aid of three other editors, the average degree of agreement between these independent reviewers was approximately 47%. Noting that each outside reviewer seemed to have a preferred column, the authors decided to present the classifications performed by Odbert. Rather than try to rationalize this decision, Allport and Odbert presented the results of their study as somewhat arbitrary and unfinished.[16]
Throughout the 1940s, researchers such as Raymond Cattell[5] and Donald Fiske[18] used factor analysis to explore the more general structure of the trait terms in Allport and Odbert's Column I. Rather than rely on the factors obtained by these researchers,[4] Warren Norman performed an independent analysis of Allport and Odbert's terms in 1963.[19] Despite finding a five-factor structure similar to Fiske's, Norman decided to use Allport and Odbert's original list to create a more precise and better-structured taxonomy of terms.[20] Using the 1961 edition of Webster's International Dictionary, Norman added relevant terms and removed those from Allport and Odbert's list that were no longer in use. This resulted in a source list of approximately 40,000 potential trait-descriptive terms. Using this list, Norman then removed terms that were deemed archaic or obsolete, solely evaluative, overly obscure, dialect-specific, loosely related to personality, and purely physical. By doing so, Norman reduced his original list to 2,797 unique trait-descriptive terms.[20] Norman's work would eventually serve as the basis for Dean Peabody and Lewis Goldberg's explorations of the "Big Five" personality traits.[21][22][23]
During the 1970s, Juri Apresjan, a founder of the Moscow Semantic School, developed the systemic, or systematic, method of lexicography which utilizes the concept of the language picture of the world. This concept is also termed the naive picture of the world in order to stress the non-scientific description of the world which is found in natural language.[24] In his book "Systematic Lexicography", which was published in English in 2000, J.D.Apresjan puts forward the idea of building dictionaries on the basis of "reconstructing the so-called naive picture of the world, or the "world-view", underlying the partly universal and partly language specific pattern of conceptualizations inherent in any natural language".[25] In his opinion, the general world-view can be fragmented into different more local pictures of reality, such as naive geometry, naive physics, naive psychology, and so forth. In particular, one chapter of the book Apresjan allots to the description of lexicographic reconstruction of the language picture of the human being in the Russian language.[26] Later, Apresjan's work was the basis for Sergey Golubkov's further attempts to build "the language personality theory"[27][28][29] which would be different from other lexically-based personality theories (e.g. by Allport, Cattell, Eysenck, etc.) due to its meronomic (partonomic) nature versus the taxonomic nature of the previously mentioned personality theories.[30]
In addition to research on personality, the psycholexical method has also been applied to the study of values in multiple languages,[31][32] providing a contrast with theory-driven approaches such as Schwartz's Theory of Basic Human Values.[33][34]
Concepts similar to the lexical hypothesis are basic to ordinary language philosophy.[35] Similar to the use of the lexical hypothesis to understand personality, ordinary language philosophers propose that philosophical problems can be solved or better understood by an examination of everyday language. In his essay "A Plea for Excuses," J. L. Austin cited three main justifications for this method: words are tools, words are not only facts or objects, and commonly used words "embod[y] all the distinctions men have found worth drawing...we are using a sharpened awareness of words to sharpen our perception of, though not as the final arbiter of, the phenomena".[36]: 182
Despite its widespread use for the study of personality, the lexical hypothesis has been challenged for a number of reasons. The following list describes some of the major critiques of the lexical hypothesis and personality models based on psycholexical studies.[8][6][35][37]