The time seems ripe for a modern statement of the division of knowledge we have called "behavior genetics." During the last two decades there have been chapter-length reviews of the area (Hall, 1951, Caspari, 1958), but no comprehensive treatment. This book is intended to fill the gap. It is not presented as a definitive work, because that would be impossible in a field of study which is in a dynamic stage of growth.
At present there are few courses labeled "behavior genetics" in American college and university curricula. Nevertheless, this book is written for a readership of advanced undergraduates and graduate students in biology and psychology. Teachers of courses in genetics and in experimental, physiological, or comparative psychology may find useful supplementary material here. We have also considered matters of concern to psychiatrists, clinical psychologists, educators, and others who must cope with individual differences among human beings. Even animal breeders may find material pertaining to their work, for selection for behavioral traits is often an important part of a breed-improvement program.
We have divided our book into three sections. Chapters I through 4 provide a general introduction to the viewpoints and techniques of behavior genetics. Chapters 5 through 9 are a survey of the literature of behavior genetics. In the final chapter, behavior genetics is successively considered as a division of population genetics and as a series of physiological-developmental problems. An attempt is made to present a theoretical framework which can serve as a guide to new areas for research.
We have had some difficulty in limiting the study of behavior genetics because of its wide range, which extends from biochemistry, through various branches of biology, to psychology, psychiatry, social science, and statistical methods. Since we could not hope to qualify as experts in all of these fields, we trust we have not erred seriously in relating our particular subject to other scientific disciplines.