Joseph M. Horn is an American psychology

Psychology

Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

 professor known for his work on adoption studies.

Horn received his Ph.D. from 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...

 and currently teaches at the University of Texas at Austin

University of Texas at Austin

The University of Texas at Austin is a state research university located in Austin, Texas, USA, and is the flagship institution of the The University of Texas System. Founded in 1883, its campus is located approximately from the Texas State Capitol in Austin...

. His research interests include intelligence and personality and their development, individual differences more generally, and vocational behavior. His research using behavior genetics is perhaps most influential.

Importantly, he initiated the Texas Adoption Project in 1972, recruiting over 500 adopted children, their biological mothers, and adoptive parents and sibs. This ongoing longitudinal study has led to numerous publications shedding light on human development and the roles of genes and environments in behavior

The key, surprising, findings are summarised in this quote:

The first phase of the study tested the personality and intelligence of adopted children between three and fourteen years-old; then the study re-tested them again as adolescents and young adults ten years later. Not only were the adoptees much more like their biological mothers than their adoptive mothers, but as they grew older, they became increasingly more similar to the biological parents they had not seen since shortly after their birth, and the less like the adopting parents who had raised them. By adolescence, the adoptees showed virtually no similarity to their adopting parents or the adoptive siblings with whom they had been raised. The study concluded that about fifty percent of the individual differences in IQ and personality were due to heredity and the remainder to [unshared] environmental influences.

In 1994 he was one of 52 signatories on "Mainstream Science on Intelligence

Mainstream Science on Intelligence

Mainstream Science on Intelligence was a public statement issued by a group of academic researchers in fields allied to intelligence testing that claimed to present those findings widely accepted in the expert community...

," an editorial written by Linda Gottfredson

Linda Gottfredson

Linda Susanne Gottfredson is a professor of educational psychology at the University of Delaware and co-director of the Delaware-Johns Hopkins Project for the Study of Intelligence and Society. Gottfredson's work has been influential in shaping U.S...

 and published in the Wall Street Journal, which declared the consensus of the signing scholars on issues related to race and intelligence

Race and intelligence

The connection between race and intelligence has been a subject of debate in both popular science and academic research since the inception of intelligence testing in the early 20th century...

 following the publication of the book The Bell Curve

The Bell Curve

The Bell Curve is a best-selling and controversial 1994 book by the Harvard psychologist Richard J. Herrnstein and political scientist Charles Murray...

.

Selected works

• Horn, J. M., Loehlin, J. C., & Willerman, L. (1979). Intellectual resemblance among adoptive and biological relatives. Behavior Genetics, 9, 177-207.
• Horn, J. M. (1983). The Texas Adoption Project: Adopted children and their intellectual resemblance to biological and adoptive parents. Child Development, 54, 268-275.
• Loehlin, J. C., Horn, J. M., & Willerman, L. (1990). Heredity, environment, and personality change: Evidence from the Texas Adoption Project. Journal of Personality, 58, 221-243.

External links

• Joseph Horn webpage at University of Texas at Austin
  University of Texas at Austin
  The University of Texas at Austin is a state research university located in Austin, Texas, USA, and is the flagship institution of the The University of Texas System. Founded in 1883, its campus is located approximately from the Texas State Capitol in Austin...
  
  
• Highlights of Pioneer Fund Research and Grantees