Navigation is Magic

	When I was a youngster my family always had one sort of boat or another. By the time I was learning the times table in school, my father was teaching me how to navigate in the coastal waters of Southern California. I fell in love with navigation. When I got to university I had the chance to begin sailing competitively on boats in the 25 – 55 foot range. Because I already knew how to read a chart and plot a course, I was often asked to do the navigation. This led me deeper into navigation, and into an interest in sailboat racing tactics. I even learned how to navigate by the stars. Every navigator who has ever crossed an ocean using celestial navigation, then predicted a landfall and seen it happen as predicted knows that navigation is more than a skill, it’s a magical art. The rise of inexpensive, extremely accurate, and easy to use global positioning systems has been a death knell for celestial navigation. I own a sextant that cost several hundred dollars in the mid-1970s. Using this and other tools, I could, under good conditions at sea, plot the boat’s position to an accuracy of about .5 nautical miles in about 30 minutes of work. A handheld GPS now costs less than one hundred dollars, provides a position accurate to a few meters, and does this hundreds of times each second. I am probably in the last generation of sailors to learn celestial navigation. GPS takes most of the work out of navigation, the magic now belongs to engineers, but the fun still belongs to the sailor.
	Micronesian Navigation When I began my postdoc in Cognitive Science at UCSD in 1978, many of my colleagues were reading Thomas Gladwin’s “East is a Big Bird” which describes the navigation accomplishments of the peoples of Micronesia. As a navigator in our own tradition, I was fascinated and mystified by the ability of a Micronesian navigators to sail hundreds of miles of open ocean with no tools other than their brains and bodies, and reliably make landfall on islands that are no more than tiny specks of land in a vast sea. I read everything I could find on this topic, and tried to work out a detailed account of how navigators could do such a thing. Some interesting clues came from the work of German Ethnographers who were in the Western Pacific in the end of the 19^th and beginning of the 20^th century. Later European and American researchers consistently tried to interpret the Micronesian system in terms of the unquestioned assumptions of our own tradition of navigation. One of the most interesting aspects of Micronesian navigation is that the navigators say that once they are out of sight of land they imagine the canoe to be stationary while the islands ahead of them move toward them, the islands off to the side slide by, and the islands aster fall further behind. This puzzling assumption that the islands move actually reduces the complexity of the problem of articulating the motion of canoe, islands, and the framework of the stars. Western navigators prefer to think in terms of absolute motion, but there are situations where a relative motion conception is superior. This is described in my paper with Geoffrey Hinton titled “Why the islands move” (Perception, vol. 13: 1984). I believe I succeeded in finding an adequate account of Micronesian navigation, but because I was not able to sail with these navigators, I cannot be sure. My efforts to work this out are reported in Hutchins (1980), Hinton and Hutchins (1984), and in chapter 2 of my 1995 book, Cognition in the Wild.
	Maneuvering Board In the early 1980s I went to work for the Navy Personnel Research and Development Center as a Personnel Research Psychologist (they did not know how to hire an anthropologist.) The Navy was having difficulty teaching radar navigation. The radar navigation courses at the Operations Specialist schools had failure rates near 30%. This matters because radar navigation techniques are used to do essential jobs like determining how to change course and speed to avoid a collision at sea. This, and more complex problems such as how to steam out from a task force for reconnaissance, and then to rejoin the task force later, are solved using radar navigation plotting techniques on a polar coordinate plotting sheet called the maneuvering board. What could be so difficult about simple plotting techniques? To find out, I entered a maneuvering board class. I attended lectures, worked through the assignments, and interviewed instructors and students. I thus began with an ethnographic study of a classroom. In the course of my work, it became clear to me that there was a single subtle conceptual misunderstanding underlying most of the difficulties encountered by the students. They all came to the classroom equipped with robust perceptual reasoning strategies that permit them to understand depictions of absolute motion. This is what we all understand as folk. If someone shows you a bird’s-eye-view animation of a ship moving on a chart, or a vehicle moving on a terrestrial surface, you know how to interpret the motion. If you see two vehicles in motion, you still know how to interpret the motion, although judging whether or not two vehicles will collide is not always easy. The conceptual problem was that the students were trying to apply the strategies that work well for absolute motion to the movement of targets on a radar screen. The motion of objects on a radar screen is relative to the motion of the vehicle on which the radar is mounted. It is thus relative motion, rather than absolute motion. Relative motion again! My work on Micronesian navigation led me to think hard about the relations among frames of motion in expressions of motion. James Hollan, Donald Norman, and I went on to design a computer-based training system for radar navigation that incorporated the insights of my ethnographic studies. The software system was originally written in UCSD Pascal and ran on the Terak microcomputer. It included a micro-world in which the student could explore the relationships between relative and absolute motion (upper image at left) and a tutorial facility that allowed the student to move step-by-step through radar navigation procedures. This system reduced the failure rate in radar navigation courses at the Operation Specialist school from 30% to about 3%. A reworked version of this program subsequently became standard refresher training for radar navigation aboard every ship in the US Navy.
	Bridge Navigation Field research on radar navigation and steam propulsion aboard ships kept me in dark interior spaces. As a navigator myself, I was interested in how navigation was conducted on the bridge of Navy ships. So, I went to sea on a series of ships studying bridge navigation. My work on this topic is reported in my book Cognition in the Wild.