Louis Leon Thurstone (29 May 1887 – 29 September 1955) was an American pioneer in the fields of

psychometrics Psychometrics is a field of study within psychology concerned with the theory and technique of measurement. Psychometrics generally refers to specialized fields within psychology and education devoted to testing, measurement, assessment, and ...

and psychophysics. He conceived the approach to measurement known as the

law of comparative judgment The law of comparative judgment was conceived by L. L. Thurstone. In modern-day terminology, it is more aptly described as a model that is used to obtain measurements from any process of pairwise comparison. Examples of such processes are the compa ...

, and is well known for his contributions to

factor analysis Factor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved variables called factors. For example, it is possible that variations in six observed ...

. A ''

Review of General Psychology ''Review of General Psychology'' is the quarterly scientific journal of the American Psychological Association Division 1: The Society for General Psychology. The journal publishes cross-disciplinary psychological articles that are conceptual, the ...

'' survey, published in 2002, ranked Thurstone as the 88th most cited psychologist of the 20th century, tied with John Garcia,

James J. Gibson James Jerome Gibson (; January 27, 1904 – December 11, 1979) was an American psychologist and is considered to be one of the most important contributors to the field of visual perception. Gibson challenged the idea that the nervous system ...

David Rumelhart David Everett Rumelhart (June 12, 1942 – March 13, 2011) was an American psychologist who made many contributions to the formal analysis of human cognition, working primarily within the frameworks of mathematical psychology, symbolic artif ...

Margaret Floy Washburn Margaret Floy Washburn (July 25, 1871 – October 29, 1939), leading American psychologist in the early 20th century, was best known for her experimental work in animal behavior and motor theory development. She was the first woman to be grante ...

, and Robert S. Woodworth.

Background and history

Louis Leon Thurstone was born in

Chicago, Illinois (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

, to Swedish immigrant parents. Thurstone originally received a master's degree in

mechanical engineering Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, an ...

from

Cornell University Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to tea ...

in 1912. Thurstone was offered a brief assistantship in the laboratory of

Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventi ...

. In 1914, after two years as an instructor of geometry and drafting at the

University of Minnesota The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public land-grant research university in the Twin Cities of Minneapolis and Saint Paul, Minnesota, United States. ...

, he enrolled as a graduate student in psychology at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...

(PhD, 1917). He later returned to the University of Chicago (1924–1952) where he taught and conducted research; among his students was James Watson, who co-discovered the structure of DNA. 1952, he established the L. L. Thurstone Psychometric Laboratory at the

University of North Carolina The University of North Carolina is the multi-campus public university system for the state of North Carolina. Overseeing the state's 16 public universities and the NC School of Science and Mathematics, it is commonly referred to as the UNC Sy ...

Chapel Hill Chapel Hill or Chapelhill may refer to: Places Antarctica * Chapel Hill (Antarctica) Australia *Chapel Hill, Queensland, a suburb of Brisbane *Chapel Hill, South Australia, in the Mount Barker council area Canada * Chapel Hill, Ottawa, a neighbo ...

Factor analysis and work on intelligence

Thurstone was responsible for the standardized mean and standard deviation of IQ scores used today, as opposed to the

Intelligence Test An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term ''Intelligenzqu ...

system originally used by

Alfred Binet Alfred Binet (; 8 July 1857 – 18 October 1911), born Alfredo Binetti, was a French psychologist who invented the first practical IQ test, the Binet–Simon test. In 1904, the French Ministry of Education asked psychologist Alfred Binet to ...

. He is also known for the development of the

Thurstone scale Louis Leon Thurstone (29 May 1887 – 29 September 1955) was an American pioneer in the fields of psychometrics and psychophysics. He conceived the approach to measurement known as the law of comparative judgment, and is well known for his cont ...

. Thurstone's work in factor analysis led him to formulate a model of intelligence centered on "Primary Mental Abilities" (PMAs), which were independent group factors of intelligence that different individuals possessed in varying degrees. He opposed the notion of a singular

general intelligence The ''g'' factor (also known as general intelligence, general mental ability or general intelligence factor) is a construct developed in psychometric investigations of cognitive abilities and human intelligence. It is a variable that summarizes ...

that factored into the scores of all psychometric tests and was expressed as a mental age. In 1935 Thurstone, together with EL Thorndike and JP Guilford, founded the journal ''

Psychometrika ''Psychometrika'' is the official journal of the Psychometric Society, a professional body devoted to psychometrics and quantitative psychology. The journal covers quantitative methods for measurement and evaluation of human behavior, including ...

'' and also the Psychometric Society, going on to become the society's first president in 1936. Thurstone's contributions to methods of factor analysis have proved valuable in establishing and verifying later psychometric factor structures, and have influenced the hierarchical models of intelligence in use in intelligence tests such as WAIS and the modern Stanford-Binet IQ test. The seven primary mental abilities in Thurstone's model were ''verbal comprehension'', ''word fluency'', ''number facility'', ''spatial visualization'', ''associative memory'', ''perceptual speed'', and ''reasoning''.

Contributions to measurement

Despite his contributions to factor analysis, Thurstone (1959, p. 267) cautioned: "When a problem is so involved that no rational formulation is available, then some quantification is still possible by the coefficients of correlation of contingency and the like. But such statistical procedures constitute an acknowledgement of failure to rationalize the problem and to establish functions that underlie the data. We want to measure the separation between the two opinions on the attitude continuum and we want to test the validity of the assumed continuum by means of its internal consistency". Thurstone's approach to measurement was termed the

. He applied the approach in psychophysics, and later to the measurement of psychological values. The so-called 'Law', which can be regarded as a measurement model, involves subjects making a

comparison Comparison or comparing is the act of evaluating two or more things by determining the relevant, comparable characteristics of each thing, and then determining which characteristics of each are similar to the other, which are different, and t ...

between each of a number of pairs of stimuli with respect to magnitude of a property, attribute, or attitude. Methods based on the approach to measurement can be used to estimate such scale values. Thurstone's Law of comparative judgment has important links to modern approaches to social and psychological measurement. In particular, the approach bears a close conceptual relation to the

Rasch model The Rasch model, named after Georg Rasch, is a psychometric model for analyzing categorical data, such as answers to questions on a reading assessment or questionnaire responses, as a function of the trade-off between the respondent's abilities, ...

(Andrich, 1978), although Thurstone typically employed the

normal distribution In statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is : f(x) = \frac e^ The parameter \mu ...

in applications of the Law of comparative judgment whereas the Rasch model is a simple logistic function. Thurstone anticipated a key epistemological requirement of measurement later articulated by Rasch, which is that relative scale locations must 'transcend' the group measured; i.e. scale locations must be invariant to (or independent of) the particular group of persons instrumental to comparisons between the stimuli. Thurstone (1929) also articulated what he referred to as the ''additivity criterion'' for scale differences, a criterion which must be satisfied in order to obtain interval-level measurements.

Awards and honors

Thurstone received numerous awards, including: Best Article,

American Psychological Association The American Psychological Association (APA) is the largest scientific and professional organization of psychologists in the United States, with over 133,000 members, including scientists, educators, clinicians, consultants, and students. It ha ...

(1949); Centennial Award,

Northwestern University Northwestern University is a private research university in Evanston, Illinois. Founded in 1851, Northwestern is the oldest chartered university in Illinois and is ranked among the most prestigious academic institutions in the world. Charte ...

(1951); Honorary Doctorate,

University of Göteborg The University of Gothenburg ( sv, Göteborgs universitet) is a university in Sweden's second largest city, Gothenburg. Founded in 1891, the university is the third-oldest of the current Swedish universities and with 37,000 students and 6000 st ...

(1954). Thurstone was President of

(1933) and first President of the American Psychometric Society (1936). ''L.L. Thurstone'' (Human Intelligence)
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Selected works

* ''The Nature of Intelligence'' (London: Routledge. 1924) * ''The Effect of Motion Pictures on the Social Attitudes of High School Children'' Ruth C. Peterson & L.L. Thurstone, MacMillan, 1932 * ''Motion Pictures and the Social Attitudes of Children'' Ruth C. Peterson & L.L. Thurstone, MacMillan, 1933 *''The Vectors of Mind. Address of the president before the American Psychological Association, Chicago meeting, September, 1933'' ( Psychological Review, 41, 1–32. 1934) * ''

The Vectors of Mind ''The Vectors of Mind'' is a book published by American psychologist Louis Leon Thurstone in 1935 that summarized Thurstone's methodology for multiple factor analysis. Overview ''The Vectors of Mind'' presents Thurstone's methods for conductin ...

'' (Chicago, IL, US: University of Chicago Press 1935) *''Primary mental abilities'' (Chicago: University of Chicago Press. 1938) * ''Multiple-Factor Analysis'' (Chicago: University of Chicago Press. 1947) * ''The Fundamentals of Statistics'' (MacMillan: Norwood Press. 1925)

References

Sources

* * * * * * * * *

External links

The Vectors of Mind 1934

{{DEFAULTSORT:Thurstone, Louis Leon Cornell University College of Engineering alumni University of Chicago alumni Intelligence researchers Fellows of the American Statistical Association American people of Swedish descent 1887 births 1955 deaths Presidents of the American Psychological Association