SPECIAL ISSUE $4.95 MYSTERIES MIND OF THE NEW AND UPDATED EXPLORATIONS OF HOW WE THINK, HOW WE BEHAVE AND WHAT WE FEEL Mind-Body Connections Happiness Depression Dreams Consciousness Memory Violence Copyright 1997 Scientific American, Inc. FROM THE EDITORS ® The Persistent Mystery of Our Selves M aster detective Hercule Poirot, the hero of many an Agatha Christie novel, boasted repeatedly about the power of “the little gray cells” in his head to solve the toughest mysteries. For philosophers, writers and other thinkers, however, those little gray cells have been the greatest mystery of all. How do a couple of pounds of spongy, electrically active tissue give rise to a psychological essence? How do we emerge from the neural thicket? E mpirical scientists may be relative newcomers to this investigation (unlike the philosophers, they’ve been on the case for only a few hundred years), but they have taken long strides forward in that short time. In this special issue of Scientific American, some of the lead- To be conscious that we are perceiving or thinking is to be conscious of our own existence. —Aristotle Memory is the cabinet of imagination, the treasury of reason, the registry of conscience, and the council chamber of thought. —St. Basil Established 1845 Scientific American Mysteries of the Mind is published by the staff of Scientific American, with project management by: John Rennie, EDITOR IN CHIEF Michelle Press, MANAGING EDITOR David Pope, PROJECT EDITOR W. Wayt Gibbs, Kristin Leutwyler, STAFF WRITERS Art Edward Bell, ART DIRECTOR Lisa Burnett, PRODUCTION EDITOR Bridget Gerety, PHOTOGRAPHY EDITOR Copy Maria-Christina Keller, COPY CHIEF Molly K. Frances; Daniel C. Schlenoff; Terrance Dolan; Katherine Wong Administration Rob Gaines, EDITORIAL ADMINISTRATOR Sonja Rosenzweig Production Richard Sasso, ASSOCIATE PUBLISHER/ VICE PRESIDENT, PRODUCTION William Sherman, DIRECTOR, PRODUCTION Carol Albert, PRINT PRODUCTION MANAGER Janet Cermak, MANUFACTURING MANAGER Tanya DeSilva, PREPRESS MANAGER Silvia Di Placido, QUALITY CONTROL MANAGER Carol Hansen, COMPOSITION MANAGER Madelyn Keyes, SYSTEMS MANAGER Carl Cherebin, AD TRAFFIC; Norma Jones Circulation Lorraine Leib Terlecki, ASSOCIATE PUBLISHER/ CIRCULATION DIRECTOR The whole machinery of our intelligence, our general ideas and laws, fixed and external objects, principles, persons, and gods, are so many symbolic, algebraic expressions. —George Santayana Advertising Kate Dobson, ASSOCIATE PUBLISHER/ADVERTISING DIRECTOR OFFICES: NEW YORK: Meryle Lowenthal, NEW YORK ADVERTISING MANAGER Randy James; Thomas Potratz, Elizabeth Ryan; Timothy Whiting. CHICAGO: 333 N. Michigan Ave., Suite 912, Chicago, IL 60601; Patrick Bachler, CHICAGO MANAGER DETROIT: 3000 Town Center, Suite 1435, Southfield, MI 48075; Edward A. Bartley, DETROIT MANAGER WEST COAST: 1554 S. Sepulveda Blvd., Suite 212, Los Angeles, CA 90025; Lisa K. Carden, WEST COAST MANAGER; Tonia Wendt. 225 Bush St., Suite 1453, San Francisco, CA 94104; Debra Silver. CANADA: Fenn Company, Inc. DALLAS: Griffith Group Business Administration Joachim P. Rosler, PUBLISHER Marie M. Beaumonte, GENERAL MANAGER Alyson M. Lane, BUSINESS MANAGER Constance Holmes, MANAGER, ADVERTISING ACCOUNTING AND COORDINATION Chairman and Chief Executive Officer John J. Hanley Corporate Officers Robert L. Biewen, Frances Newburg, John J. Moeling, Jr., Joachim P. Rosler, VICE PRESIDENTS Anthony C. Degutis, CHIEF FINANCIAL OFFICER JOHN RENNIE, Editor in Chief [email protected] Program Development Linnéa C. Elliott, DIRECTOR Electronic Publishing Martin O. K. Pau