Our data indicate that CSS instructions in the United States are currently written at a reading level that is too high. Experts in the arena of health literacy recommend that materials be targeted to the fifth- or sixth-grade reading level…. The average readability level of the instruction sets that we tested was 10th grade. Researchers … found that approximately two thirds of parents tested in an outpatient clinic could not read at more than a ninth-grade level…. Because parents would be expected to be the main target for CSS instruction sets, this lends additional evidence that the instruction sets may not be reaching the people most likely to benefit from the message. (Wegner and Girasek, 2003, p. 590)

On the face of it, the study confirms general beliefs about the failure of American education to produce verbally literate people who can read polysyllabic words; the authors used the SMOG (Simple Measure of Gobbledygook) statistic based on the number of three or more syllable words in text samples. They recommended that “manufacturers of CSS rewrite their instruction sets to a fifth-grade reading level. This could be accomplished by using shorter sentences and simpler words” (Wegner and Girasek, 2003, p. 591).

In the committee’s judgment, a second message can be drawn. Wegner and Girasek (2003, p. 590) noted that “[t]his study did not take into account some factors that tend to increase comprehensibility, such as the use of illustrations and empty space …” because “… [p]ictures and diagrams were not considered, neither were captions that stood apart from the rest of the instruction set and applied only to pictures” (Wegner and Girasek, 2003, p. 589).

That many car safety seats are improperly installed should come as no surprise to any adult American. The problem is not simply one of comprehension as a function of word complexity, sentence length, and therefore, verbal literacy. Comprehension is a function of another form of literacy, one that is equally essential but largely overlooked. Spatial literacy lies at the heart of spatial thinking. It was unfortunate that Wegner and Girasek chose not to include the pictures and diagrams because installation instructions are a complex combination of text and graphics.

For anyone who has attempted to assemble a child’s bicycle, a piece of furniture, a stereo system, or a ceiling fan (Figure 3.1), the challenge of language is only part of the problem. Instructions control actions. Words have referents, physical objects, and those referents must be correctly identified, aligned, and brought together. Directions such as up and down, front and back, on top of and behind, and left and right become crucial in establishing relations between parts. Parts must be linked into a working whole. Motions involving clockwise versus counterclockwise turns, through versus over versus under, and push versus pull must be distinguished. The coordination among text, schematic diagram, and required actions is critical to success in the assembly process.

Spatial thinking is so deeply embedded in the activities of daily life and thought that it is difficult to disentangle and appreciate its role. We may not even realize its role, but it is fundamental to many taken-for-granted activities, underpinning their successful performance and sometimes accounting for their spectacular failure. Imagine, therefore, a classic middle-class family with two parents and children of various ages. Imagine a typical day in the life of that family. Imagine solving the problems of everyday life.

A phone call in late August to a daughter on a study-abroad program in Europe requires, among other things, working out the right time to call. This requires an understanding of time zones and the use of daylight saving time. A trip to take a son to college involves packing things into boxes and packing boxes into a car trunk and back seat in the most efficient way such that space use is maximized, nothing gets crushed or broken, and things are easy to remove. Getting to the college town and apartment building involves using a web-based search engine to print a route map, and then following written and map directions. The exercise machine that was disassembled and packed has to be reassembled without, unfortunately, the instructions, which have been lost. The now-assembled bunk bed, desk, and shelves have to be fitted into the room without blocking heating vents, electrical outlets, telephone outlets, and the passage to the window, closet, and door in the

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