Early Man's Movements

In response to your report "How Man Began" ((SCIENCE, March 14)), I would note that the nearly 2 million-year age, reported as the key breakthrough in dating hominids in Java, used to be found in textbooks of the 1970s and early '80s. But later years of investigation by teams from Japan, the Netherlands and Indonesia reset the age of these hominids to little more than 1 million years. A true revolution in our thinking about a complex of multiple human lineages, each with a proper extinction, stays intact with either the older- or younger-date theory. Geographic expansion is a critical theme in prehistory, underlying the global scale of present human dilemmas. Its direct study is in a very young phase, poorly served by superficial portrayals.

Rick Potts, Director

Human Origins Program

National Museum of Natural History

Washington