This outstanding volume describes the author's persistent efforts to overcome the roadblocks encountered at every step as she tried to uncover the details of the study. Segal adopts a sympathetic tone in describing the impact of the research on adopted twins who discover each other. At the same time, she pulls no punches in identifying the ethical issues that the researchers should have considered. This masterful book will appeal to readers interested in developmental psychology, research ethics, research methodology, personality, behavior genetics, and theories of psychology. Highly recommended. Lower- and upper-division undergraduates. Graduate students and faculty. General readers.
— Choice Reviews
In the 1930s a famous radical behaviorist had conjectured that given a dozen healthy infants he could take anyone at random and transform in any type of specialist, doctor, lawyer, and even beggar and thief, regardless of children’s tendencies or abilities. This was a thought experiment, which has never been carried out in practice, and the reasons are obvious. It would be antithetical and unimaginable. Generations of psychology students take knowledge and debate this thought experiment during their undergraduate courses. This was a thought experiment, which has never been carried out in practice, and the reasons are obvious. Now we find that unlike the radical behaviorist, who was strictly ethical, a group of psychoanalysts and psychiatrists conducted the experiment with twins, without parents’ knowledge, in the 1960s. Professor Nancy Segal, Director of the Twin Studies Center at California State University, Fullerton, wrote the book Deliberately Divided about this controversial study of twins and triplets adopted apart and observed until they turned twelve. Segal opened the archives of history and analyzed the information in-depth on the basis of her decades of experience working with twins. As a professor of psychology, I consider this an important book for the formation of students and I recommend its translation into Portuguese.
— Emma Otta, Instituto de Psicologia/Universidade de São Paulo
The documentary Three Identical Strangers captivated viewers with the story of identical triplets who were separated at birth, studied by psychiatrists, and kept unaware of one another’s existence. Deliberately Divided is the inside story of the history and science behind this disturbing event, told by a leading researcher and a gifted expositor.
— Steven Pinker, Johnstone Professor of Psychology, Harvard University, and author of “The Blank Slate” and “Rationality”
Before reading Deliberately Divided it never occurred to me that a book on the study of twins could be a gripping drama. Yet here, Nancy Segal, herself a professor of psychology (and a twin), writes so movingly about an unfortunate twin study that deliberately left many twins to grow up apart. Was this disruption of human lives worth the cost just to learn something about human nature? I was on the edge of my seat waiting to find out what happened when the long-separated twins found each other later in life. This is one of the most educational and entertaining books on psychology I’ve ever read.
— Elizabeth F. Loftus, distinguished professor, University of California, Irvine and former president, Association for Psychological Science
This is surely the last word on studies of twins raised apart, the most profound experiment nature has to offer on the relative contributions of genes and the environment to the makeup of the human personality. Nancy Segal has given us a career’s-worth of insight into the twin experience.
— Lawrence Wright, author of “Twins” and “The Plague Year"
A rich, moving, and comprehensive account of a human drama every living person can identify with. Being both a twin and a twin researcher with deep experience in the domain under discussion, Dr. Segal brings a unique perspective to bear on the moral and ethical issues this controversial study raises. She touches every base with clarity, compassion, intelligence and common sense.
— Thomas J. Bouchard, Jr., PhD, Professor Emeritus, Department of Psychology, University of Minnesota
Deliberately Divided is a superb read! Written by Nancy L. Segal, a top international expert on twin research, the book conveys the amazing stories of the twins, their families, and the investigators behind a controversial study of intentionally separated twins and triplets who were secretly studied in the 1960s–70s. Deliberately Divided is a must-read for anyone concerned with human studies, research ethics, and the welfare of children. You will be riveted from start to finish as I was.
— Nicholas G. Martin, PhD, editor, “Twin Research and Human Genetics”
Segal’s expertise on twins raised apart, primarily from her training and work on the Minnesota Study of Twins Reared Apart, makes her the ideal researcher to write this current book.... An incredible amount of detective work was needed to put together the very complicated minutiae of this story of how twins and triplets were separated and how they were studied. Segal does a strong job of describing her entire data collection process.... Researchers and others who became aware of this series of events from recent films, such as Three Identical Strangers, will find the details provided in Segal’s book to be illuminating....
— Behavior Genetics
Typical of all of her books, Deliberately Divided couples Segal’s research skills, worthy of those of a Pulitzer-class investigative journalist, with rigorous scientific interpretations and her own perceptive ideas and insights regarding what may or may not have actually happened and why. Her combination of fascinating accounts about the twins, their families, and the protagonists at LWS-CDC and her in-depth treatment of the scientific, legal, and ethical issues surrounding the controversial study will make the book appealing to readers from all walks of life. The whole book is the epitome of sound scholarship and makes fascinating reading
— ScienceDirect
Deliberately Divided [is] the most thorough account of this scandalous episode to date. Segal is an eminent behavioral geneticist who has spent her career wrestling with issues raised by the study of twins, and her new book is by turns moving, infuriating, and enraging. Everybody who thinks about human nature and scientific research should read it…. One of the strengths of Segal’s account is its dispassionate and thorough analysis of the ethical thorns and tangles of the LWS-CDC study. She clearly finds the study abhorrent…[b]ut she does not allow her outrage to overwhelm her prose or cloud her judgment.... Deliberately Divided is a well-researched and careful book about a shameful episode in the history of US science. Segal is scrupulously fair and has refused to fill her book with caricatured villains and blemishless heroes. Drs. Neubauer and Bernard are presented as three-dimensional humans who are likable, intelligent, and even admirable, but also severely flawed. It is to Segal’s credit that she allows the reader to see this while also unequivocally denouncing all involved for their behavior.
— Quillette
This book contains a subtly nuanced, and balanced discussion of these issues and a sympathetic study of the personalities and attitudes involved, and the scientific and moral climate at the time which led to this twin study. It can serve a lesson to researchers of how the allure of making significant findings can blind them to the ethics of what they are doing. There are few scholars more eminent in the field of twin studies than Nancy Segal with at least eight books and over 250 publications to her name. It is therefore unsurprising that she manages to draw together with ease, economy, and clarity the findings on twins relevant to this, her latest, book. When she was asked to write about this controversial area, she had misgivings, but in the end she agreed. This highly readable book is the result, in which she deftly steers a course between the science of twins, the ethics of research, the interests and feelings of those twins studied and the histories and personalities of the people involved….This book is full of rich detail, clearly described and placed in context… Segal’s grasp of detail and ability to order it clearly is most impressive.
— Human Ethology
[T]o call this book detailed is like calling Mount Everest an interesting pile of rocks – it just doesn’t quite capture its full nature and grandeur. The details, however, do not overpower what is a highly readable and informative book. Segal truly captures the totality of the stories of the individuals impacted by these events and a reader will experience a wide range of emotions throughout the book’s chapters…. An incredible story requires an incredible storyteller, and Segal completely delivers. She is uniquely suited to tell this story an informed manner as she can speak to the overall science and methodology of twin studies. Perhaps more importantly, she also possesses the experience and care to properly elucidate and contextualize the multitude of stories surrounding the LWS-CDC study – especially those of the twins and their families. This book is a must-read not only for those interested in the etiologies of the human condition, but also for any researcher or student of psychology and human development.
— Evolution & Human Behavior
Nancy Segal is an extraordinary expert who has been devoted to twin studies for most of her professional life. Thanks to this experience, her presentation encompasses much more than a single research project. She knows the detailed stories of hundreds of twins from the unique cohorts of twins who were reared apart or switched-at-birth (Segal, 2012). Her talent as a writer has presented readers with several books on these topics, and perhaps no one could better tell the story of the LWS-CDC study, which has shocked the viewers of the TV shows and films about the study. It is quite easy to take the side of the creator of the hottest news. But truth requires sensitivity, expertise in the field of the research object, and Socrates’ ability to catch and explain contradictions and change optics, to reveal the motivation of all participants in the described. In this book, Segal managed to accomplish those feats.
— Twin Research and Human Genetics
Segal’s ability to dramatically describe stories of twin separation, loss and reunion offers the reader an unforgettable experience of coming to know the twins and triplets involved in the study. The book is impressively researched and meticulously told.
— Twinless Twins Newsletter
Deliberately Divided uses its platform to demonstrate and restore respect for the many individuals (especially, but not only the twins and triplets) impacted by the study. It calls contemporary researchers to reflect on how such events could have transpired-and how we must hold ourselves and our colleagues to higher ethical standards to ensure that such disrespect for persons does not reoccur.
— Monash Bioethics Review