When we are startled by the new, confronted with discrepancies, our knowing gives way to uncertainty—and changes. In the distinctive manner that has made him one of the most influential forces in developmental psychology, Jerome Kagan challenges scientific commonplaces about mental processes, pointing in particular to the significant but undervalued role of surprise and uncertainty in shaping behavior, emotion, and thought.

Drawing on research in both animal and human subjects, Kagan presents a strong case for making qualitative distinctions among four different types of mental representation—perceptual schemata, visceral schemata, sensorimotor structures, and semantic networks—and describes how each is susceptible to the experience of discrepancy and the feeling of surprise or uncertainty. The implications of these findings are far-reaching, challenging current ideas about the cognitive understandings of infants and revealing the bankruptcy of contemporary questionnaire-based personality theory. More broadly, Kagan’s daring, thoroughly informed, and keenly reasoned book demonstrates the risks of making generalizations about human behavior, in which culture, context, and past experience play such paramount and unpredictable roles.

Kagan’s reassessment of research on infants is the most important part of his new book. His arguments on the subject are controversial, of course, and should provoke a much-needed discussion. So the book will make a real contribution to the debate, and is definitely worth reading. -- Peter Bryant * Nature *
We have come to expect erudite, penetrating, expansive, and scholarly work from Jerome Kagan. Surprise, Uncertainty, and Mental Structures does not disappoint. Kagan, arguably more than any other developmental scientist, has helped to make the study of infancy an important scholarly enterprise. This volume further elucidates the significance of infancy for psychological science… Surprise, Uncertainty, and Mental Structures fills a void with extensions to later development and personality that has been lacking… No other book addresses this niche and no other book conveys the significance of infancy with comparable depth, rigor, and eloquence. -- Philip Roman Zelazo * Contemporary Psychology *
Kagan puts forth some intriguing ideas, among them that psychologists must move beyond process and discover the mechanisms or structures that underlie those processes… The discipline of psychology is well served by his broad-ranging study. -- M. W. York * Choice *

Jerome Kagan was Daniel and Amy Starch Research Professor of Psychology Emeritus at Harvard University.