This book is my attempt to develop a comprehensive picture of the origins and early development of industrial-organizational (I-O) psychology. The time period covered is from the late 1800s until the early 1930s, an interval that saw what was then called industrial psychology evolve from the initial efforts of a handful of individuals to an established professional field. Narrowing the focus to the early years allows me to offer a more fine-grained analysis than writing a history of I-O psychology from the beginning to the present day. I view this book as primarily a work of synthesis, using primary and secondary sources to create an overview of the origins and early years of I-O psychology with an appreciation for both context and those individuals important in its development. Much of the historical work in I-O psychology has been justly criticized as overly focusing on developments in the United States.Footnote ¹ I-O psychology developed in many countries; I have tried to reflect the global nature of its history. The United States does receive proportionally more coverage than other countries, however, because of its central role in the history of I-O psychology and because of my own limitations in accessing non-English relevant materials.

The structure of the book is neither strictly chronological nor strictly topical. I considered both approaches. The former proved too disjointed due to the uneven development of various content areas; the latter required excessive repetition and loss of narrative drive. I compromised with a hybrid approach: roughly chronological, combining coverage of topic areas with biographical sketches of important contributors that present the entire arc of their lives and careers. Psychology applied to employee selection was at the heart of early industrial psychology, and it receives attention appropriate to its importance in this narrative.

All narrative history tells a story. In shaping that story, I had to decide what is relevant from the large amount of information available. It is impossible to include everything. While all history is told from a particular perspective, one should consciously avoid an unfairly biased perspective. This is easier said than done, as I am enough of a psychologist to realize that we are not always aware of our biases and that it is very difficult to step outside one’s cultural and educational experiences. While my intention was to write an accurate, balanced account of the origins and early years of I-O psychology, it is critical to stress that this is a history, not the history. Other histories, with different perspectives, emphases, and information, are possible, inevitable, and welcome.

In writing this history of the beginning years of I-O psychology, I tried to find a balance between what are sometimes referred to as the “old” and “new” historiographical approaches to the history of psychology. External influences and context are important, but so are the actions and ideas of the participants, including biographical information relevant to their contributions. While this is a critical history in the sense that discontinuities and missteps are discussed, I believe that real progress occurred, and those accomplishments are noted. I used primary sources when possible and secondary sources when it was not or when those secondary sources added nuance or contributed to an understanding of the material. This was particularly true for non-English material. While I tried to write a history sensitive to how the historical actors would have experienced events at that time, I do at times draw connections between past and current research and practice, not to judge necessarily (although there is some of that) but to illustrate similarities and differences.

Deciding how much of a background in I-O psychology I could assume the reader possesses was a difficult question to answer. An earlier draft of this book was geared to a relatively naïve reader with little or no background in I-O psychology, statistics, measurement, or historiography. It even included a primer on I-O psychology, summarizing the content areas that comprise the field. Despite my efforts, reviewers noted that the book was, in fact, more suitable for a reader with some knowledge of I-O psychology, although not necessarily one who is familiar with historiography. While I did excise the primer, I have included explanatory footnotes explaining statistical and I-O psychology procedures and terms that may be unfamiliar, and included a section on historiography to introduce that topic to the reader who may be familiar with I-O psychology but not with historical research. It is my hope that the book can be read profitably by anyone with an interest in the history of I-O psychology.