Robert Boyd and Joan B. Silk bring their respective specialties to the groundbreaking Fourth Edition of How Humans Evolved. Using the broad perspective of behavioral ecology?how human behavior has been influenced by the evolutionary process?the authors offer a balanced discussion, drawing on updated coverage of the human fossil record. The well-structured pedagogical framework of the text, with its emphasis on overarching ideas, makes the material accessible to introductory students. New Science and Recent Discoveries The Fourth Edition integrates discussions of new science and recent discoveries into the narrative. Highlights of the Fourth Edition include: Updating of the fossil record to reflect the most current scholarship. Expanded coverage of gene regulation and cell differentiation during development. Discussion of life history theory linked with the evolution of primates? cognitive abilities. New data on the origin of primates, the New World primate radiation, and Miocene apes. New data on global paleoclimates; new research by McLarnon on Homo ergaster?s lack of speech. New discussion of recent works by Christopher Dean on rates of development in extinct hominins. New sections on the Herto fossils and what genetic sequence data can tell us about human evolution. Revised sections that provide a more integrated view of human diversity and contemporary human behavior. New examination of how evolution has shaped the psychology underlying decisions about mating and parenting and new analysis of human behavior toward mates and children. Excellent Art Program The art program in How Humans Evolved clearly demonstrates the relationships between fossils. All of the comparative drawings are pictured with the same orientation and consistent scale throughout the book. A Responsive Revision For the Fourth Edition, the authors have responded to feedback from the hundreds of instructors across the country already using How Humans Evolved and have streamlined the text into 17 chapters.