Sunday, January 31, 2010

Environment and Heredity in Adoption

Heredity and Environment in 300 Adoptive Families: The Texas Adoption Project (Hardcover)
~ Joseph Horn (Author), John Loehlin (Author)

Most likely Gladney, though it doesn't say so in the description.

Product Description
This book presents the results of a thirty-five-year research project involving 300 families, each of whom adopted at least one child at birth from a Texas home for unwed mothers during the period of 1962-1970.

The book weaves together information about the birth parents of the adopted children; information about the adoptive parents; and information about the children in these families. Children adopted at birth have two sets of parents. Birth parents provide their adopted-away child with a genetic
endowment, but do not participate in shaping the child's environment. Adoptive parents do not contribute genetically, but are otherwise in charge of directing the child's development.

If adopted children grow up to resemble birth parents they have never seen, the clear inference is that hereditary factors have had an influence. Environmental factors are implicated whenever children resemble their adoptive parents, but not the birth parents. The Texas Adoption Project was designed to investigate the impact of genetic and environmental factors. This unique and innovative longitudinal study is written for specialists and the educated public.

An introductory guide is provided for the non-specialist reader explaining the form and statistical content of the tables. Additional technical material for specialists is contained in appendices. This important contribution to the literature on adoption will also be of interest to those interested in the relative weight of genetics and environment in human development.


Joseph M. Horn is an American psychology professor known for his work on adoption studies.
Horn received his Ph.D. from the University of Minnesota and currently teaches at the University of Texas at Austin. Research interests include intellectual and personality development, behavior genetics, personality, individual differences, and vocational behavior.

Horn is a Pioneer Fund grantee. Of interest to the Pioneer Fund is Horn's Texas Adoption Project started in 1972, a longitudinal study of over 500 adopted children, their biological mothers, and adoptive parents and siblings. The controversial Pioneer Fund claims that Horn's work is evidence of a hereditarian influence:

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 environmental influences.

As for J. C. Loehlin, he has published substantial material on the
intelligence component of the nature/nurture studies.

The study abstract is here and here.

Thanks to Jo Ann Swanson for finding this yet unreleased book we will all be looking for.


legitimatebastard said...

For those of us who lived this, yes, it is painfully obvious that adoptees physically resemble the parents who conceived and gave birth to them, whether they are known as in reunion, or unknown to the adoptee. Intelligence and aptitudes, talents and disabilities are also inherited.

If an adoptee is given respect and encouragement by their adoptive parents to develop inborn talents and tendencies, the adoptee is free to express their innate abilities.

If adoptive parents see learning disabilities, for example, and the adoptee is given prompt remedial help, corrections can be made. Same as with medical issues, such as glasses or teeth braces or serious medical conditions.

If the adoptee is squashed by adoptive parents to be models and imitations of the adoptive parents, then the adoptee's natural abilities are not recognized nor encouraged.

The children of adoptees also inherit from their parents. They grow into adults who also pass on genetic traits, this is common sense. While the environment influences such aspects of life as food, clothing, shelter, economic opportunities, or poverty, or divorce, or wealth, if a person has no mathematical ability or no ability for mechanical or technical thinking, no amount of elementary schooling or higher education is going to "make" a difference. People have different wirings in their brains. This is natural.

If a child of an adoptee has innate abilities for artistic talent or musical talent, those tendencies will show up regardless of adoptive parent/adoptive grandparent influence of money, power, and educational opportunities.

My adult son physically resembles my natural mother who died when I was an infant. It helps that his father also has dark hair and eyes, but close examination of photographs and comparisons with other family members clearly shows my son’s resemblance to the grandmother he has never known. He is tall, while his father is short. He has inborn artistic talent that came from me, and I inherited that from both my deceased mother and my father.

My daughter physically resembles her father, actually, her father’s mother and father, more than she does me. However, she has recessive genes that can be clearly observed in both sets of grandparents. My daughter has her father’s talents and aptitudes, while she does not have any ability for fine arts at all. That’s okay. My son and I cannot sing, but she can sing.

Temperaments and personality types are also inherited. Introvert and extrovert, for example; natural leaders and followers, people who work alone and people who work with people…all inherited.

Please, people, please educate yourselves. Stop making adoptees and their children fit into boxes they are not meant to be stuffed into! Let us be free to be who we are!

RegNMINiles said...

I comment on this statement: "Most likely Gladney, though it doesn't say so in the description."

I agree with that statement. But A review of this book, by Thomas Jackson, was pub. in> American Renaissance, vol. 21, no. 6 (Jun. 2010). The magazine's advertisement says the study is about the Methodist Mission Home in San Antonio, Texas.

That may be true.

Reg Niles
Founder, Adoption Bibliography Center

RussiaToday Apr 29, 2010 on Russian Adoption Freeze

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RT: Russia-America TV Interview 3/10

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