Heredity and Environment in 300 Adoptive Families: The Texas Adoption Project

253 Pages·2010·4.07 MB·English

by  Joseph Horn

Heredity and Environment in 300 Adoptive Families
Heredity and Environment in 300
Adoptive Families
The Texas Adoption Project
Joseph M. Horn
and
John C. Loehlin
First published 2010 by Transaction Publishers
Published 2017 by Routledge
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Library of Congress Catalog Number: 2009023281
Library of Congress Cataloging-in-Publication Data
Horn, Joseph M.
Heredity and environment in 300 adoptive families: the Texas adoption
project / Joseph M. Horn and John C. Loehlin.
p. cm.
Includes bibliographical references and index.
ISBN 978-0-202-36345-5
1. Adoption--Texas--Case studies. 2. Parent and child--Texas--Case studies.
3. Parents--Texas--Case studies. I. Loehlin, John C. II. Title. III. Title:
Heredity and environment in three hundred adoptive families.
HV875.56.T4 H67 2010
362.73409764--dc22
2009023281
ISBN 13: 978-0-202-36345-5 (hbk)
Contents
Preface
1. A Brief History and Overview of the Project
1. Why Carry Out (or Read about) an Adoption Study?
2. Previous Adoption Studies
3. The Texas Adoption Project—Beginnings
4. Some Characteristics of the Sample
5. Studies in the Texas Adoption Project—Chronological
Sequence
6. Summary and Look Ahead
2. Intellectual Abilities in the Texas Adoption Project
1. About the Presentation of Results in this Book
2. Intelligence and Intelligence Tests
3. Evidence about Heredity and Environment from
Comparisons of Means
4. Evidence about Heredity and Environment from Family
Correlations
5. More Specialized Aspects of Intelligence
3. Personality in the Texas Adoption Project
1. Personality Measures Used in the TAP
2. The Rating Composites
3. The Cattell Scales
4. The CPI and the TTS in the Separate Mail Study
5. The MMPI
6. Personality Change
4. Achievement, Adjustment, Outcomes
1. Academic Achievement
2. Psychopathology and Problem Behavior
3. Occupation
4. Personal Relationships
5. Maturity and Happiness
6. Factors Related to Outcomes
5. Summary and Conclusions
1. The Story so Far
2. What We Learned in the TAP
3. Four Families
4. Some Limitations of Adoption Studies
5. Some Implications of the Texas Adoption Project
6. Final Comments
Appendices
A. Initial Letter to Families
B. Rating Scales
C. IQ Test Details
D. Details on Self-Ratings
E. Modeling of Selection
Glossary
References
Index
Preface
This book describes a thirty-five-year study of three hundred families who
adopted a child from a Texas home for unwed mothers during the years 1963 to
1971. (These children are thus now adults.) The study was initiated and directed
by Joseph M. Horn, at the time a fresh young University of Minnesota PhD on
the Psychology faculty of the University of Texas at Austin. He soon recruited
two of his colleagues, John Loehlin and the late Lee Willerman, to assist him in
the study. The rest, as they say, is history.
The present book sketches the history of the project and brings together its
many findings—currently scattered through various articles in professional
journals—plus a few hitherto unpublished results reported here for the first time.
We conclude with a discussion of the implications of these findings for two
groups of people: first, for those directly concerned in one way or another with
adoptions; and second, for those of us—surely most of us—who wonder from time
to time about the differences among the individuals around us. This is because an
adoption study lets us separate the two things that parents provide children: their
genes and their family environments. In adoptive families, one set of parents
provides the former and another set of parents provides the latter.
We have tried to write this book so as to make it accessible to general readers.
For this reason, we have minimized the number of direct citations in most parts
of the text—if present, they take the form of (author’s surname, date), which
should let you find them in the reference list at the back of the book if you wish.
Otherwise, notes at the beginnings of chapters provide sources for material
covered in that chapter. The book contains many numerical tables, but we have
tried to keep them simple, and have provided an introduction to them at the
beginning of Chapter 2. Finally, there is a glossary of technical terms at the back
of the book, preceding the references.
It remains in this preface to acknowledge the many people and institutions
who have contributed in one way or another to this particular scientific
enterprise.
First, and most critical, are the members of the three hundred adoptive families
that participated in the study. Although for reasons of confidentiality we cannot
name them, we want to assure each participating member of each one of the
families that we deeply value the time and effort that he or she contributed to the
project.
Next, we are grateful for the institutional support we have received. The
original study was financed by the National Institute of Mental Health, through
its grant MH2480. The separate mail study and the ten-year follow-up were
supported by the National Science Foundation, through grants BNS7902918 and
BNS8209882. Later phases of the project were supported by the Pioneer Fund. We
are grateful to its presidents Harry F. Weyher, Jr., and J. Philippe Rushton for
their help. Our institutional home, the Psychology Department of the University
of Texas at Austin, has supported us and continues to support us in many ways.
And finally, the Methodist Mission Home of San Antonio has played a central
and essential role in the research. We are grateful to its three successive
presidents, Spencer Stockwell, Harold Burkhardt, Jr., and Larry Watson for their
wholehearted support of the study. In particular, without Dr. Stockwell’s
foresight in gathering data on the birth mothers, this book would simply not
exist. We are also grateful to the Home’s consulting psychologist, Arthur G.
Bouton, who contributed in a major way to the testing; and to many members of
the Methodist Mission Home staff, including Lillian Smith, Bertha Cardwell, Bea
Pearce, Dorothy Johnson, Mona McDonald, Mildred Miller, and others, who
helped in contacting the adoptive families, providing data from the files, and in
other ways.
Many individuals at the University of Texas played important roles in the
project. Administrative Assistants Carol Weegar and Carol Shirley worked
successively to keep things moving; later, Jody Ernst took on that task in addition
to doing her dissertation work on the project and carrying out some of the home
interviews. Many graduate students in the Psychology Department were involved
in the project at one time or another; among those (in addition to Jody) were
Richard Arnold, Jeremy Beer, Richard Bouton, Ralph Carney, Marilyn Erickson,
Mary Green, Nancy Lawson, Ashleigh Merritt, Marsha Peterson, Gerald Turner,
and David Vaughan. Finally, a number of undergraduate research assistants
participated in various ways, including data entry, assistance with mailings, and
rating of interviews. Among these were Jennifer Clemens, Jessica Cundiff, Eliot