Metaphors for Teaching Paragraph Unity and Coherence

by Tina Blue
December 25, 2006

My college students hear a lot about beads.  In various configurations, beads serve as useful metaphors for the presence or absence of essential elements of composition, like unity and coherence in paragraph structure.


To enable them to visualize unity, I ask my students to imagine each paragraph as a box of colored beads, with each box containing beads of just one color. One paragraph is, let's say, full of blue beads; the next, full of red beads; the third, full of yellow beads--and so on. I warn them that to maintain paragraph unity, they need to keep the beads from leaking out of their proper box and getting mixed in with the beads in another box. The red beads from the second paragraph need to stay in the second paragraph. I shouldn't be finding red beads in the blue, green, or yellow paragraphs.

As a classroom exercise to illustrate this concept, I give them a sample essay with paragraphs that fail to maintain their integrity. We identify the main point of each paragraph and highlight each paragraph's topic sentence (if, that is, the writer has provided one). Each topic sentence gets its own color. Then we use that same color to highlight every sentence in the paragraph that deals with the main point of that paragraph.

After we have colored the sentences in all the paragraphs that stick to the topic of their paragraph, then we go through and color the sentences that don't stay on topic. We decide which of the other paragraph topics the stray sentences deal with and use the appropriate colors to highlight them. If, as sometimes happens, we find sentences that don't fit any of the paragraphs' topic sentences, then we use a not yet dedicated color--or more than one, if the maverick sentences deal with more than one topic not covered in the topic sentences of the essay's established paragraphs.

When we have finished highlighting our sentences in all different colors, we have a striking display of the essay's problems with unity, as well as an illustration of the aspects of incoherence that are related to a lapse in paragraph unity.

When a student sees an otherwise solid yellow paragraph marred by a red sentence, a blue sentence, and a pink sentence, then the paragraph's lack of unity is self-evident. Equally self-evident is the fact that those sentences belong with the paragraphs that are highlighted in those colors.

And if one or more sentences show up in colors that belong to no paragraph in the essay, then that reveals another type of problem with the paper. Either the writer has introduced random ideas that don't belong in the essay at all, or he has failed to write a paragraph that develops an idea that needs to be developed.


I also use beads to illustrate coherence. Let's assume that a paragraph has unity--i.e., all the beads are of one color. That by itself doesn't ensure that it has coherence. Each sentence in a paragraph has to derive logically from the one that precedes it and lead logically to the one that follows it. In other words, the sentences should be like links in a chain, not like beads on a string. When a paragraph's sentences are not arranged coherently, even if they are all one color, then I call that "bead-stringing." One way to test for bead-stringing is to move some of the sentences around. If they are logically linked, then changing their order will affect their meaning. But if they are just a bunch of sentences about a single topic, rather than a coherent, directed development of an idea, then they don't necessarily have to be in the order they are in. That is evidence of structural weakness in the paragraph.

Even worse than bead-stringing is a structural problem I call "bag o' beads."  When a paragraph suffers from the bag o' beads syndrome, its points are all jumbled together in such a random order that it can't even be called bead-stringing. In a truly bad case of bag o'beads, the beads in a paragraph might not even be all of the same color.

Having explained each of these concepts, I can then use them as a kind of shorthand to tell a student what has gone wrong with a paragraph. Sometimes the entire essay is bead-strung (or just a bag o' beads), but often the problems occur in just one or two paragraphs.

The bead imagery gives them something to visualize, and that helps them understand the otherwise abstract concepts of unity, direction, and coherence.  The images are also vivid enough (and humorous enough) for easy recall.
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