Lloyd G. Humphreys (12 December 1913—7 September 2003) was a differential psychologist and methodologist who focused on assessing individual differences in human behavior. December 12 is the 346th day (347th in leap years) of the year in the Gregorian calendar. ... 1913 is a common year starting on Wednesday. ... September 7 is the 250th day of the year (251st in leap years). ... 2003 is a common year starting on Wednesday of the Gregorian calendar. ... Psychology (Classical Greek: psyche = soul or mind, logos = study of) is an academic and applied field involving the study of behaviour, mind and thought and, frequently, the application of such knowledge to various spheres of human activity, including problems of individuals daily lives and the treatment of mental illness. ...

Born in Lorane, Oregon, Humphreys earned his undergraduate degree at the University of Oregon in 1935, a master's from Indiana University in 1936, where he first learned about factor analysis, then received his doctorate at Stanford in 1938, studying under Ernest Hilgard. His dissertation on partial reinforcement effect (or the Humphreys effect), is considered a classic in the field. University of Oregon The University of Oregon (UO) is a Public University located in Eugene. ... 1935 was a common year starting on Tuesday (link will take you to calendar). ... Indiana University may refer to: the Indiana University system Indiana University of Pennsylvania This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... 1936 was a leap year starting on Wednesday (link will take you to calendar). ... Factor analysis is a statistical technique that originated in mathematical psychology. ... (The wind of freedom blows. ... 1938 was a common year starting on Saturday (link will take you to calendar). ...

His first position was at Northwestern University (1939–1945). He was a Carnegie Fellow in Anthropology (1941–1942, Columbia University) during that time, then taught at the University of Washington (1946–1948) and Stanford (1948–1952). He then took a post as Research Director, Personnel Laboratory, for the United States Air Force (1951–1957). He then spent the remainder of his career at the University of Illinois (1957–1984). The Arch, the main entrance to Northwesterns Evanston campus Northwestern University is a private university which has its main campus in Evanston, Illinois, on a 240-acre (970,000 m²) campus along the shore of Lake Michigan. ... Columbia University is a private university in New York City. ... The University of Washington, founded in 1861, is a major public research university in the Seattle metropolitan area. ... (The wind of freedom blows. ... Seal of the Air Force. ... The University of Illinois is the set of three public universities in Illinois. ...

Humphreys argued that much psychological research fails to replicate because of inadequate sample sizes, because correlations fluctuate when Ns are small. His own empirical research typically involved large-scale longitudinal studies such as Project TALENT (Flanagan et al., 1962). The power of a statistical test is the probability that the test will reject a false null hypothesis, or in other words that it will not make a Type II error. ...

In the 1970s, Humphreys chaired the American Psychological Association's Task Force on ability and achievement testing. He deemed a general intelligence test ‘‘the single most important test that can be administered for vocational guidance purposes’’ (Humphreys, 1985, p. 211). He also coined the concept "inadequate learning syndrome" (ILS) and argued it was a more important social problem than the AIDS epidemic (Humphreys, 1988). The American Psychological Association (APA) is a professional organization representing psychology in the US. It has around 150,000 members and an annual budget of around $70m. ...

Amid the controversy generated by publication of The Bell Curve in 1994, Humphreys wrote a target article (Humphreys, 1994), which stimulated a series of comments by a number of prominent scholars in the field. He generated further controversy by accepting money from the Pioneer Fund, a eugenics organization. The Bell Curve is a controversial book published in 1994 by Richard J. Herrnstein and Charles Murray exploring the role of intelligence in understanding social problems in America. ... 1994 was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ... The Pioneer Fund is a foundation that aims to advance the scientific study of heredity and human differences. ... Eugenics is the self-direction of human evolution: Logo from the Second International Congress of Eugenics, 1921, depicting it as a tree which unites a variety of different fields. ...

His work is among the most widely cited in intelligence research, and he received many prestigious awards in this field. Intelligence is usually said to involve mental capabilities such as the ability to reason, plan, solve problems, think abstractly, comprehend ideas and language, and learn. ...

References

Flanagan, J. C., Dailey, J. T., Shaycoft, M. F., Gorham, W. A., Orr, D. B., & Goldberg, I. (1962). Design for a study of American youth. Boston, MA: Houghton Mifflin.

Humphreys LG (1939). The effect of random alternation of reinforcement on the acquisition and extinction of conditioned eyelid reactions. Journal of Experimental Psychology, 25, 141–158.

Humphreys, L. G. (1985). General intelligence: An integration of factor, test, and simplex theory. In B. B. Wolman (Ed.), Handbook of intelligence ( pp. 201–224). New York: Wiley.

Humphreys, L. G. (1988). Trends in levels of academic achievement of blacks and other minorities. Intelligence, 12, 231–260.

Humphreys, L. G. (1994). Intelligence from the standpoint of a (pragmatic) behaviorist. Psychological Inquiry, 5, 179–192.

Lubinski D (2004). [www.vanderbilt.edu/Peabody/SMPY/HumphreysObit.pdf Lloyd G. Humphreys: Quintessential Scientist (1913–2003)]. (PDF Intelligence 32 (2004) 221–226. PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ...