Reading for Results - Online Practice
Drawing Logical Inferences

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Directions: Choose the main idea implied by each paragraph. When you do, remember the following:

  1. The implied main idea must be backed up by most of the statements in the paragraph. It shouldn’t rely on just one or two sentences.
  2. Nothing in the paragraph should contradict the implied main idea.
  3. The main idea you choose should rely more heavily on what the author actually says rather than what you think about the topic.
  4. The main idea you infer should function just like an author’s topic sentence: It should sum up all or most of the sentences in a paragraph.

1. Is there any truth to the claim that drinking red wine prevents heart disease? One study of twelve healthy volunteers (eight men and four women) attempted to find out. The subjects in the study drank 250 ml of either regular red wine or de-alcoholized red wine over a ten-minute period. Thirty minutes later, researchers measured the subjects’ blood flow and dilation, or expansion, of their arteries. They found that, for all of the subjects, the diameter of the brachial artery*, blood flow, and heart rate increased significantly. Because those who drank the de-alcoholized beverage exhibited even more pronounced effects, researchers determined that alcohol did not cause the changes. They theorized that the antioxidants present in grape skins, one of the ingredients in red wine, were responsible. Other studies, however, suggest that it’s not just the grape skins in red wine that help the heart. These studies found that alcohol increases the levels of a protective cholesterol, which prevents blood platelets from clumping together and triggering a heart attack. Still other studies have found that tannins from the oak wood containers used to store red wine also seem to inhibit platelet clumping and thereby reduce heart attacks.
*The brachial artery is the major blood vessel located in the upper arm.
Implied Main Idea
a. Wine is good for your health.

b. Studies suggest that certain ingredients in red wine help prevent heart disease.
c. Research shows that it’s the grape skins in red wine that provide benefits for the heart.

2. Every year troops of researchers journey to the world’s rain forests. Although they spend some of their time on the forest floor, they spend more of it rummaging through the canopy, or the tops of rain forest trees. Some of those researchers come in pursuit of flowers with scents that might become the basis for a new perfume. Others are flown to the rain forest by food companies desperate for a new taste sensation that will help them corner the world’s markets. Medical researchers come to hunt for plants that might help cure diseases. As Kelsey Downum, a biologist at Florida International University, says about the rain forest: "About 60 percent of all our medicines originally come from plants; there is much more to be found." Aware of the riches that can be found in the rain forest’s canopy, researchers of all kinds worry about the future. The rain forest is disappearing as the trees are cut down for wood and the jungle cleared for farming. (Quotation from Marlise Simons, "Eau de Rain Forest," The New York Times Magazine, May 2, 1999, p. 61.)
Implied Main Idea
a. Researchers of all kinds explore the rain forest’s canopy in search of nature’s riches and are fearful of what may be lost should the rain forest disappear.

b. Were the rain forest to disappear, modern medicine would make no new advances in cures for deadly diseases.
c. The rain forest attracts many different kinds of researchers, but it’s the medical researchers who are the most important.

3. Electronic cigarettes, or e-cigarettes, are battery-powered electronic gadgets that are supposed to provide a safe alternative to smoking cancer-causing cigarettes. Packing nicotine but no tobacco, they are advertised as a way for smokers to get their nicotine without smoking tobacco-filled cigarettes, which produce something like 60 different carcinogens, or cancer-causing agents. However, a 2014 study published in the May issue of Nicotine and Tobacco Research concluded that when heated at high temperatures, the ingredients in e-cigarettes, or e-cigs, produce formaldehyde, which is a known carcinogen. Makers of e-cigarettes insist that e-cigarettes are safe. But a second study, also set to appear in the same journal, has come to the same conclusion as the first. Maciej L. Goniewicz, lead researcher on the study published in May, insists that e-cigarettes can only be considered safe if testing is done not just on the ingredients in them but also on the vapor produced once they are heated.
Implied Main Idea
a. Some research suggests that smoking e-cigarettes might also pose potential cancer risks.

b. Studies have conclusively proved that e-cigarettes are as dangerous to our health as tobacco-filled cigarettes.
c. Makers of e-cigarettes have consistently underplayed their product’s health hazards.

4. Mules don’t get much respect. On the contrary, it’s commonly assumed that they are both stubborn and stupid. Yet mules are very smart. That’s one of the reasons they are considered stubborn when they are anything but. What they are is cautious. Faced with a dangerous climb, they will move slowly and carefully no matter what the rider or pack leader wants. That attitude shows common sense, not stupidity. Bred from the mating of a female horse with a male donkey, mules generally inherit the donkey’s strength and the horse’s athleticism (if not its speed). In the early 20th century, mules were widely used in military transport units. Unlike horses, they functioned well amid the noise and confusion of war. They were not easily spooked and would continue on with their task even when bullets flew over their heads.
Implied Main Idea
a. Mules are much smarter than horses.

b. Mules don’t deserve their generally bad reputation.
c. Mules are among the smartest members of the animal kingdom.

5. "Follow your instincts," "Listen to your inner voice," and "Trust your gut" are common expressions that all suggest the same thing: We can rely on ourselves to successfully chart the course of our lives—it’s the voices of others that get us into trouble. Or is it? According to psychologists Daniel Gilbert and Timothy Wilson, it might be a good idea to put a little less faith in our own self-knowledge. This is especially true when we consider our future satisfaction. The research of Gilbert and Wilson suggests that our valuation of future happiness depends a lot on our current feelings, and those feelings can change with time. When Gilbert and Wilson asked a group of professors what would guarantee their happiness, the subjects generally agreed that tenure would do the trick. But when the researchers went back and talked to those same professors—some had received tenure and some had not—they made an interesting discovery. Those who hadn’t gotten tenure were just as happy as those who had. Other researchers have had similar findings about predictions concerning what counts as a soul-shattering event. People who thought, for instance, that they would be destroyed by the onset of a crippling disease turned out to be much tougher than they thought. While the disease changed their lives, they still retained the capacity for enjoyment, even joy. Psychologists Piercarlo Valdesolo and David DeSteno made similar discoveries about self-knowledge when they asked subjects about their willingness to cheat on a coin-flipping test that could earn or spare them an unpleasant task to complete. All the researcher’s subjects insisted they would play fair. But, in fact, they did not. Ninety percent of the participants found a way to make the coin flip turn out the way they wanted—for example, continuously flipping until they got the right result—so they could avoid the unpleasant task. Then they insisted they had played fair because they had good reasons for not following the instructions they had been given.
Implied Main Idea
a. People cannot accurately predict what will make them happy.

b. Not many people in this world are willing to play fair when playing fair means they could lose.
c. In general, people may not possess the accurate self-knowledge that they think they do.

Last change made to this page: 05/09/14

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