It is the passage of the islands under the stars which is used for etak, the reckoning of distance traveled on a voyage. More specifically, one island is selected for each seaway and used throughout every voyage as a reference…. Ideally this island is fifty or so miles to one side of the line of travel and roughly opposite the midpoint of the seaway which stretches between the islands of origin and destination. The star bearings of the reference island from both the starting and ending points of the trip are known, since on another occasion the reference island may become a destination. In between there are other navigation star positions under which the reference island will pass as it “moves” backward. Its passage under each of these stars marks the end of one etak and the beginning of another. Thus the number of star positions which lie between the bearing of the reference island as seen from the island of origin and its bearing as seen from the island of destination determines the number of etak, which can here be called segments, into which the voyage is conceptually divided. When the navigator envisions in his mind’s eye that the reference island is passing under a particular star he notes that a certain number of segments have been completed and a certain proportion of the voyage has therefore been accomplished. (Gladwin, 1970, p. 184)

This mental structure integrates speed and distance:

In sum, the contribution of etak is not to generate new primary information, but to provide a framework into which the navigator’s knowledge of rate, time, geography, and astronomy can be integrated to provide a conveniently expressed and comprehended statement of distance traveled…. It is a useful and deliberate logical tool for bringing together raw information and converting it into the solution of an essential navigational question: “How far away is our destination?” (Gladwin, 1970, p. 186)

While we advocate the development and use of tools and technologies to support spatial thinking, the Puluwatan navigators illustrate the remarkable power of spatial thinking without modern technology. They show the way in which spatial thinking is woven into the culture of a group of people. They also show the remarkable ingenuity and inventiveness of those predecessors who “invented” the system. Although the regular use of the system does not generate new primary information, those sailors who developed the suite of strategies were indeed generators of new, primary knowledge.

support systems allow for the orderly and sequenced introduction of basic concepts and skills and for the guidance of the inquiry process.

Support systems cannot and should not substitute for thought. Therefore, a support system does not replace the human process of thinking, automating it by means of a “machine.” It cannot provide a substitute for an understanding of what to do, when, how, and why. Instead, a support system provides an interactive environment within which thinking can take place. It is supportive in a variety of ways: it performs tasks that would otherwise be time-consuming and demanding in terms of effort and attention; it offers guidance in terms of options and alternatives; it provides checks and feedback; and it manages the flow of work. It is enhancing in that it allows access to a range of problem-solving strategies (heuristics and algorithms) that might otherwise be inaccessible, it fosters collaborative work by externalizing otherwise “private” processes, and it generates a range of possible answers to a question.


A support system for thinking in any domain of knowledge performs some or all of five functions:

  1. Database construction and management: provides a capacity for data acquisition, entry, formatting, storage, and management (the functional equivalent of long-term memory)

  2. Data analysis: performs operations and functions for data manipulation, analysis, interpretation, representation, and evaluation

  3. Memory: provides working memory for tracking the flow of computations and the storage

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