Louis Leon Thurstone
Encyclopedia
Louis Leon Thurstone was a U.S.
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 contributions to factor analysis
.
from Cornell University
in 1912. Thurstone was offered a brief assistantship in the laboratory of Thomas Edison
. In 1914,
after two years as an instructor of geometry and drafting at the University of Minnesota
, he enrolled as a graduate student in psychology at the University of Chicago
(PhD. 1917). He later returned to the University of Chicago (1924–1952) where he taught and conducted research. In 1952, he established the L. L. Thurstone Psychometric Laboratory at the University of North Carolina
at Chapel Hill
.
of IQ scores used today, as opposed to the Intelligence Test system originally used by Alfred Binet
. He is also known for the development of the Thurstone scale
.
Thurstone's work in factor analysis led him to formulate a model of intelligence center around "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
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 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 invaluable in establishing and verifying later psychometric factor structures, and has 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.
. 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
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
(Andrich, 1978), although Thurstone typically employed the normal distribution 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.
(1949); Centennial Award, Northwestern University
(1951); Honorary Doctorate, University of Göteborg (1954). Thurstone was President of American Psychological Association
(1932) and first President of the American Psychometric Society (1936).
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
pioneer in the fields of psychometrics
Psychometrics
Psychometrics is the field of study concerned with the theory and technique of psychological measurement, which includes the measurement of knowledge, abilities, attitudes, personality traits, and educational measurement...
and psychophysics
Psychophysics
Psychophysics quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they effect. Psychophysics has been described as "the scientific study of the relation between stimulus and sensation" or, more completely, as "the analysis of perceptual...
. He conceived the approach to measurement known as the law of comparative judgment
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...
, and is well known for his contributions to factor analysis
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, uncorrelated variables called factors. In other words, it is possible, for example, that variations in three or four observed variables...
.
Background and history
Louis Leon Thurstone was born in Chicago, Illinois to Swedish immigrant parents. Thurstone originally received a masters in Mechanical EngineeringMechanical engineering
Mechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the...
from Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
in 1912. Thurstone was offered a brief assistantship in the laboratory of Thomas Edison
Thomas Edison
Thomas Alva Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. In addition, he created the world’s first industrial...
. In 1914,
after two years as an instructor of geometry and drafting at the University of Minnesota
University of Minnesota
The University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...
, he enrolled as a graduate student in psychology at the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
(PhD. 1917). He later returned to the University of Chicago (1924–1952) where he taught and conducted research. In 1952, he established the L. L. Thurstone Psychometric Laboratory at the University of North Carolina
University of North Carolina
Chartered in 1789, the University of North Carolina was one of the first public universities in the United States and the only one to graduate students in the eighteenth century...
at Chapel Hill
Chapel Hill
Chapel Hill may refer to:*Chapel Hill, North Carolina, a town in the United States, or**the University of North Carolina at Chapel Hill, a major university within the town*Chapel Hill, Alabama...
.
Factor analysis and work on intelligence
Thurstone was responsible for the standardized mean and standard deviationStandard deviation
Standard deviation is a widely used measure of variability or diversity used in statistics and probability theory. It shows how much variation or "dispersion" there is from the average...
of IQ scores used today, as opposed to the Intelligence Test system originally used by Alfred Binet
Alfred Binet
Alfred Binet was a French psychologist who was the inventor of the first usable intelligence test, known at that time as the Binet test and today referred to as the IQ test. His principal goal was to identify students who needed special help in coping with the school curriculum...
. He is also known for the development of the Thurstone scale
Thurstone scale
In psychology, the Thurstone scale was the first formal technique for measuring an attitude. It was developed by Louis Leon Thurstone in 1928, as a means of measuring attitudes towards religion. It is made up of statements about a particular issue, and each statement has a numerical value...
.
Thurstone's work in factor analysis led him to formulate a model of intelligence center around "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
General intelligence factor
The g factor, where g stands for general intelligence, is a statistic used in psychometrics to model the mental ability underlying results of various tests of cognitive ability...
that factored into the scores of all psychometric tests and was expressed as a mental age
Mental age
Mental age is a concept in relation to intelligence, expressed as the age at which a child is performing intellectually. The mental age of the child that is tested is the same as the average age at which normal children achieve a particular score....
. In 1935 Thurstone, together with EL Thorndike and JP Guilford founded the journal Psychometrika 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 invaluable in establishing and verifying later psychometric factor structures, and has influenced the hierarchical models of intelligence in use in intelligence tests such as WAIS
Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale intelligence quotient tests are the primary clinical instruments used to measure adult and adolescent intelligence. The original WAIS was published in February 1955 by David Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale...
and the modern Stanford-Binet IQ test
Stanford-Binet IQ test
The development of the Stanford–Binet Intelligence Scales initiated the modern field of intelligence testing and was one of the first examples of an adaptive test. The test originated in France, then was revised in the United States...
.
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 law of comparative judgmentLaw 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...
. He applied the approach in psychophysics
Psychophysics
Psychophysics quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they effect. Psychophysics has been described as "the scientific study of the relation between stimulus and sensation" or, more completely, as "the analysis of perceptual...
, and later to the measurement
Measurement
Measurement is the process or the result of determining the ratio of a physical quantity, such as a length, time, temperature etc., to a unit of measurement, such as the metre, second or degree Celsius...
of psychological values. The so-called 'Law', which can be regarded as a measurement model, involves subjects making a comparison
Comparison
Comparison may refer to:-Language:* Comparison , a feature of many languages* Degree of comparison, an English language grammatical feature* Mass comparison, a test for the relatedness of languages-Mathematics:...
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
Rasch model
Rasch models are used for analysing data from assessments to measure variables such as abilities, attitudes, and personality traits. For example, they may be used to estimate a student's reading ability from answers to questions on a reading assessment, or the extremity of a person's attitude to...
(Andrich, 1978), although Thurstone typically employed the normal distribution in applications of the Law of comparative judgment whereas the Rasch model is a simple logistic function
Logistic function
A logistic function or logistic curve is a common sigmoid curve, given its name in 1844 or 1845 by Pierre François Verhulst who studied it in relation to population growth. It can model the "S-shaped" curve of growth of some population P...
. 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
Dr. Thurstone received numerous awards, including: Best Article, American Psychological AssociationAmerican Psychological Association
The American Psychological Association is the largest scientific and professional organization of psychologists in the United States. It is the world's largest association of psychologists with around 154,000 members including scientists, educators, clinicians, consultants and students. The APA...
(1949); Centennial Award, Northwestern University
Northwestern University
Northwestern University is a private research university in Evanston and Chicago, Illinois, USA. Northwestern has eleven undergraduate, graduate, and professional schools offering 124 undergraduate degrees and 145 graduate and professional degrees....
(1951); Honorary Doctorate, University of Göteborg (1954). Thurstone was President of American Psychological Association
American Psychological Association
The American Psychological Association is the largest scientific and professional organization of psychologists in the United States. It is the world's largest association of psychologists with around 154,000 members including scientists, educators, clinicians, consultants and students. The APA...
(1932) and first President of the American Psychometric Society (1936).
Selected works
- The Nature of Intelligence (London: Routledge. 1924)
- The Vectors of the Mind. Address of the president before the American Psychological Association, Chicago meeting, September, 1933 ( Psychological Review, 41, 1-32. 1934)
- Primary mental abilities (Chicago: University of Chicago Press. 1938)
- Multiple-Factor Analysis (Chicago: University of Chicago Press. 1947)