Most of us compare things all the time: You might compare two people you know well, two motorcycles you are considering buying for a cross-country tour, three Stephen King novels, four tomato plants being grown under different laboratory conditions, or two theories about the relationship between inflation and wages. But as soon as you begin to compare two things, you usually begin to contrast them as well, for rarely are two things alike in all respects. The contrasts, or differences, between the two motorcycles are likely to be more enlightening than the similarities, many of which may be so obvious as to need no analysis. Comparison, then, brings similar things together for examination, to see how they are alike. Contrast is a form of comparison that emphasizes differences. According to research on learning, we acquire new concepts most readily if we can see how they are similar to or different from concepts we already know.

Chances are that you will confront many test questions and essay assignments asking you to compare and contrast—two poems, three presidents, four procedures. This strategy is popular in all academic disciplines, for it is one of the best ways to challenge students intellectually. This chapter shows how you can organize a comparison/contrast, and it concludes with some sentence strategies you might use when comparing or contrasting.

Organizing Comparisons and Contrasts

There are two ways to organize comparison and contrast in writing: You can present the items being compared in chunks or in sequence. In chunking, each object of the comparison is presented separately; in sequencing, the items are compared point by point. For example, a chunked comparison of two motorcycles would first detail all pertinent features of the Harley-Davidson SuperLow 1200T, and then consider all features of the Kawazuki Z1000 ABS, whereas a sequenced comparison would analyze the Harley and the Kawazuki feature by feature. In a chunked comparison, the discussion is organized around the items being compared. In a sequenced comparison, it is organized around characteristics of the items being compared.

In the following example of chunked comparison, Jane Tompkins contrasts popular nineteenth-century sentimental novels with the Western novels that provided a reaction against them:

The female, domestic, “sentimental” religion of the best-selling women writers?— Harriet Beecher Stowe, Susan Warner, Maria Cummins, and dozens of others—whose novels spoke to the deepest beliefs and highest ideals of middle-class America, is the real antagonist of the Western.

You can see this simply by comparing the main features of the Western with the sentimental novel. In these books? . . . a woman is always the main character, usually a young orphan girl, with several other main characters being women too. Most of the action takes place in private spaces, at home, indoors, in kitchens, parlors, and upstairs chambers. And most of it concerns the interior struggles of the heroine to live up to an ideal of Christian virtue—usually involving uncomplaining submission to difficult and painful circumstances, learning to quell rebellious instincts, and dedicating her life to the service of God through serving others. In these struggles, women give one another a great deal of emotional and material support, and they have close relationships verging on what today we would identify as homosocial and homoerotic. There’s a great deal of Bible reading, praying, hymn singing, and drinking of tea. Emotions other than anger are expressed very freely and openly. Often there are long, drawn-out death scenes in which a saintly woman dies a natural death at home. . . .

The elements of the typical Western plot arrange themselves in stark opposition to this pattern, not just vaguely and generally but point for point. First of all, in Westerns (which are generally written by men), the main character is always a full-grown adult male, and almost all of the other characters are men. The action takes place either outdoors—on the prairie, on the main street—or in public places—the saloon, the sheriff’s office, the barber shop, the livery stable. The action concerns physical struggles between the hero and a rival or rivals, and culminates in a fight to the death with guns. In the course of these struggles the hero frequently forms a bond with another man—sometimes his rival, more often a comrade—a bond that is more important than any relation he has with a woman and is frequently tinged with homoeroticism. There is very little free expression of the emotions. The hero is a man of few words who expresses himself through physical action—usually fighting. And when death occurs it is never at home in bed but always sudden death, usually murder.

— JANE TOMPKINS,West of Everything: The Inner Life of Westerns

Schematically, a chunked comparison looks simple enough. As the preceding example shows, it is easy to block off such a discussion in a text and then provide a clean transition between the various parts. And yet it can in fact be more complicated for a writer to plan than a sequenced comparison. Sequenced comparison may be closer to the way people perceive and think about similarities or differences in things. For example, you may have realized all at once that two navy jackets are different, but you would identify the specific differences—buttons, tailoring, fabric—one at a time. A sequenced comparison would point to the differences in just this way, one at a time, whereas a chunked comparison would present all the features of one jacket and then do the same for the second. A writer using the chunked strategy, then, must organize all the points of comparison before starting to write and then be sure that the points of comparison are presented in the same order in the discussion of each item being compared. With sequencing, however, the writer can take up each point of comparison as it comes to mind.

In the next example, from a natural history of the earth, David Attenborough uses sequencing to contrast bird wings and airplane wings:

Bird wings have a much more complex job to do than the wings of an aeroplane, for in addition to supporting the bird they must act as its engine, rowing it through the air. Even so the wing outline of a bird conforms to the same aerodynamic principles as those eventually discovered by man when designing his aeroplanes, and if you know how different kinds of aircraft perform, you can predict the flight capabilities of similarly shaped birds.

Short stubby wings enable a tanager and other forest-living birds to swerve and dodge at speed through the undergrowth just as they helped the fighter planes of the Second World War to make tight turns and aerobatic manoeuvres in a dog-fight. More modern fighters achieve greater speeds by sweeping back their wings while in flight, just as peregrines do when they go into a 130 kph dive, stooping to a kill. Championship gliders have long thin wings so that, having gained height in a thermal up-current, they can soar gently down for hours and an albatross, the largest of flying birds, with a similar wing shape and a span of 3 metres, can patrol the ocean for hours in the same way without a single wing beat. Vultures and hawks circle at very slow speeds supported by a thermal and they have the broad rectangular wings that very slow flying aircraft have. Man has not been able to adapt wings to provide hovering flight. He has only achieved that with the whirling horizontal blades of a helicopter or the downward-pointing engines of a vertical landing jet. Hummingbirds have paralleled even this. They tilt their bodies so that they are almost upright and then beat their wings as fast as 80 times a second producing a similar down-draught of air. So the hummingbird can hover and even fly backwards.

—DAVID ATTENBOROUGH, Life on Earth

Attenborough finds a valid—and fascinating—basis for comparison between birds and airplanes and develops it in a way that both informs and entertains his readers. A successful comparison always has these qualities: a valid basis for comparison, a limited focus, and information that will catch a reader’s attention.