3.5: Inferences

Inferences vs. Guessing

What is an inference? What's the difference between an inference and a guess? And what does any of this have to do with college-level reading and writing?

An inference is a conclusion you reach by applying logic to the evidence you are given. Making inferences while reading is a strategy that will help you learn, remember, and apply what you have read. When you make inferences, you are "reading between the lines". This tactic is similar to what Sherlock Holmes does when he sees that Dr. Watson has a tan and makes a conclusion about where Watson has recently traveled.

You already make inferences all of the time. For example, if you go over to a friend's house and they point at the sofa and say, "Don't sit there; Candy came over with her baby again," what could you logically conclude? First, you know there must be a reason not to sit where your friend is pointing. Further, you know that the reason to not sit there is related to the fact that Cindy just visited with her baby. You don't know what exactly happened, but you can infer enough and don't need to ask any more questions to know that you do not want to sit there.

Figure: Image from Pixabay

Other examples of inferences are when a doctor makes a diagnosis about why you are sick or when a mechanic figures out what is wrong with your car. What can you infer from the image above? Try making some inferences yourself. Imagine you witness each of the following – what can you infer about each situation?

1. You see a woman pushing a baby stroller down the street.
2. You are at a corner and see two cars stopped at an intersection. The rear car starts honking its horn.
3. You are walking down the street, and all of a sudden a dog comes running out of an opened door with its tail between its legs.

For the first example, you probably came up with something simple, such as that there was a baby in the stroller. For the second, you could infer that the first car should have started moving or was waiting too long at the corner and holding up the second car. For the third, you could reasonably guess that the dog had done something wrong and was afraid of being punished. You do not know for certain that these inferences are true.

Just like Sherlock Holmes, you would have to test your theories. If you checked 100 strollers, 99 times you would find a baby, but maybe one time you would find something else, like groceries or a small dog.

Exercise \(\PageIndex{1}\)

Write a conclusion you could infer from the following:

1. You see a man running and frantically waving at a bus that is pulling away from a bus stop.
2. You are giving a speech in front of an audience and notice several people laughing and pointing at something on your pants.
3. Your sister comes home from spending the evening with her friends, slams the front door and runs to her room while crying.

Making Inferences from Reading Material

To make inferences from reading material, take two or more details from the reading and see if you can draw a conclusion. Remember, making an inference is not just making a guess even though the answer is not stated in the reading passage. You need to make a judgment that can be supported, just as you could reasonably infer there is a baby in a stroller, because even though you do not know for certain, it is the most likely possibility. For example, at the end of the story "The Five Orange Pips," you are not told what exactly happened to the Lone Star, but you can infer that it was wrecked in a storm based on the other details provided:

• There was a storm.
• The ship did not arrive at its next destination.
• Wreckage with the initials L.S. were seen by other sailors.

You could claim that the ship was taken by pirates, was sunk by a whale, or even that it landed on a deserted island; however, the only reasonable explanation from the facts is the same one implied by Dr. Watson: the ship was destroyed by the storm.

When you are asked to make an inference, go back over the reading and look for hints within the text, such as words that are directly related to the question. Also check for tone: are there words or phrases that indicate whether something is positive or negative? For example, if someone is referred to as being, sharp, friendly, and loyal, you would know that those are positive attributes, whereas if they were referred to as being slovenly, dull, and selfish, those are negative attributes.

In order to make reasonable inferences that help you better comprehend what you read, remember to do the following:

Understand the stated information. You don’t necessarily have to identify the main ideas to make a reasonable inference. However, you do need to understand the important vocabulary and facts in the text. So ask yourself, “What do these details seem to show? Is there enough evidence to support my inference?” "Are there any other possible ways to interpret this?"

Use your prior knowledge of the situation and your common sense. However, do not ignore the facts in favor of your own personal opinions.

Consider the alternatives so you don’t “jump to conclusions.” Inferences tend to be “reasonable” when they are the result of “reasoned” thinking, not emotional reactions. When you go to a doctor for advice, he or she will think of different possible diagnoses before settling on the one that is most likely, given your symptoms. If the doctor jumped too quickly to one conclusion, he might give you the wrong treatment. If, as a reader, you jump too quickly to one interpretation of the text, you may not understand what the writer intended to convey.

Example: Imagine that it is a sunny day and you decide to go see a movie. After the movie is over, you step back outside and see that the sky is now cloudy and the streets and sidewalks are all wet. What can we reasonably infer happened?

If you said that it rained while you were in the theater, you’re right! But what if you said that everything is wet because a water truck driving down the street was hit by a piano falling from an upper story window, causing the water truck to burst open and spill water all? This is a very unlikely scenario.

Questioning/responding (after you read): After you read a text, or part of a book, you will often be asked to respond to questions about the text. Just as you did when you annotated, you will often be asked to write down main ideas from the text as well as your own personal reactions to the text. Hint: Read these questions BEFORE you read the text as a pre-reading exercise. This will help you build more SCHEMA (representation of a theory in the form of an outline) about the text.

Exercise \(\PageIndex{2}\)

Read the following passage, and then determine what you can infer from the passage.

Hybrid cars are good for the environment, but they may not perform as well as cars that run only on gasoline. The Toyota Prius gets great gas mileage and has low emissions, making it a good "green" option. However, many people think that it is unattractive. The Prius also cannot accelerate as quickly as other models and cannot hold as many passengers as larger gas-fueled SUVs. Although they save money on fuel, hybrid cars cost more up front than gas-fueled cars. A new hybrid car can cost almost $3,500 more than the same car configured to run just on gasoline.

Which of the following can you infer from the passage?

1. Hybrid cars are more dangerous than other options.
2. Toyota is making a lot of money from the Prius.
3. Cars that use gasoline are going to destroy the environment.
4. Hybrid cars may not be the best choice for everyone.

Answer

You will notice right away that there is nothing about car safety in the passage at all, so you can eliminate choice A. Choice B could be the answer, since the passage mentions that hybrids cost more to purchase. But is it the most reasonable conclusion?

To be sure, you need to go through all of the answers – don't just stop when you find one that looks okay. You may think that choice C is true; after all, many people want hybrid cars because emissions are harmful to the environment. Although this choice seems accurate, it does not follow from anything in the passage. Choice D could be inferred from the text. If a person had a large family, was short on money or needed a car that could accelerate quickly, then a hybrid might not be the best choice for them.

Now compare choice D with the other possible answer, choice B. Choice B might not be as good an answer because you don't know how much it costs Toyota to make the cars, and you don't know how many they sell, so you can't reasonably infer that they are making a lot of money. Choice D is the correct answer.

Exercise \(\PageIndex{3}\)

Read the following passage, and then determine what you can infer from the passage.

Redwood trees are rare. They are found only on the coastal slopes of Northern California and Oregon, and in China. Redwoods were thought to be extinct in China, but they were rediscovered by a Chinese forester in 1948. These trees can grow hundreds of feet high and live to be thousands of years old. They are endangered due to logging, pollution, and global warming, which is reducing the amount of fog on the coast. Redwoods get their water from the fog.

Which of the following can you infer from the passage:

1. The Chinese logged the Redwoods almost into extinction.
2. Redwood trees will continue to grow taller throughout their whole lives.
3. Using non-recyclable products will kill Redwood trees.
4. Redwoods can only grow in places that get a lot of fog.

Paragraph 2:

Shannelle is a very good baker. Whenever there is a bake sale to raise money for a cause, Shannelle is always asked to make cupcakes or a pie. People say that they only come to the bake sales if they know that Shannelle is making something. She always agreed to bake things because she hated to say no to anyone. One week, her oven broke and she could not bake, so she decided to go for a hike instead. Shannelle enjoyed it so much that she realized she needed to learn to make time for herself, and not just donate all of her free time to charity.

Which of the following can you infer from the passage:

1. Shannelle is a generous person.
2. Shannelle's mother did a good job teaching her how to bake.
3. The people in the community were taking advantage of Shannelle.
4. Shannelle's brother broke her oven so she would get a day off.

Building on Your Knowledge of Inferences

Previously, we covered the basics of inferences and reasonable conclusions. Now we are going to look at another strategy to help you make valid inferences: the if-then statement. To use an if-then statement, look at the information presented in the reading and see if you could rephrase it into a statement using the words "if" and "then", which establish a cause-and-effect relationship.

For example:

In the 1800s in England, laws were applied differently depending on the gender of the accused. Women could not own land or vote. Women were barred from receiving a death sentence for crimes that a man could be executed for because people thought it would be too shocking to see a woman hanged publicly. In some places, men could be fined for certain behaviors done in the presence of a woman, such as swearing or spitting, but not if those same behaviors were done only in the presence of men.

What if-then statements could we make based on the paragraph above? Let's go through sentence-by-sentence.

1. If we were back in England in the 1800s, then the laws would be applied differently for men and women.
2. If we were back in England in the 1800s, then women could not own land or vote.
3. If a woman committed a capital crime ("capital" meaning one that could earn a death sentence), then she would not be executed.
4. If a woman were hung, then the public would be shocked.
5. If a man swore in the presence of a woman, then he could be fined.

Broken down like this you can see how much easier it is to make logical inferences. Suppose you were asked if a woman who murdered her husband would be executed.

If-then statement #3 would tell you that the answer is "no," even though that information is not directly mentioned in the text. If you were asked if women were involved in government, you would say "no" because you know that they could not vote (#2). If you were asked if men could own real estate, you would say "yes" because #2 indicates that the fact that women could NOT own real estate was different from what men could do.

Exercise \(\PageIndex{4}\)

Now do the same thing with the next paragraph. Write your if-then statements first, then your inferences, and then check your work below.

Many people don't realize that our sun is actually a star. Our sun seems very large because it is so close to us; however, some stars are actually much larger than our sun. Betelguese (pronounced beetle-juice), a star located in the constellation Orion, is much larger than our own sun. In fact, if it were located where our sun is located, its surface would engulf both Earth and Mars. Because other stars are so distant, they appear to be fainter, which is why we cannot see them in the daytime. Betelguese is the 8th brightest star in the night sky. To find Betelguese, first locate the constellation Orion. This star forms his left shoulder.

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Answer

These are just examples, but your answers should be similar to them.

If something is far away, then it will appear smaller. If something looks smaller, then it may not be smaller if it is far away.

From here, there are dozens of conclusions you could infer. For example, if you were asked why Star A appears smaller than Star B, you would know it might be because it is actually smaller. Then again, it might also appear smaller because it is farther away. The if-then statement is a useful strategy that can help you make inferences and increase your reading comprehension.

• If a star is much larger than the sun, then it could be Betelguese.
• If a star is fainter than the sun, then it cannot be seen during the day.
• If a star is the 8th brightest in the night sky, then it is Betelguese.
• If you know which constellation a star is in, then it is easier to find.

Exercise \(\PageIndex{5}\)

Write an if-then statement for each sentence in the following paragraphs.

1) Nicaragua is the largest country in Central America. The population in Nicaragua, hovering at approximately 6 million, is multiethnic. Segments of the population include indigenous native tribes from the Mosquito Coast, Europeans, Africans, Asians, and people of Middle East origin. The main language is Spanish although native tribes on the eastern coast speak their native languages, such as Miskito, Sumo, and Rama, as well as English Creole. The mixture of cultural traditions has generated substantial diversity in art, cuisine, literature, and music.

2) Childhood obesity is a condition where excess body fat negatively affects a child's health or well-being. Since methods to directly determine the amount of body fat are difficult, the diagnosis of obesity is often based on the Body Mass Index (BMI). Due to the rising prevalence of obesity in children and its many adverse health effects, obesity is being recognized as a serious public health concern. The term "overweight" is often used instead of "obese" for children because it is less stigmatizing.

Contributors and Attributions

• Adapted from Making Inferences. Provided by: Saylor Academy. CC-BY: Attribution Unported.
• Adapted from Writing for Success. Provided by: The Saylor Foundation. CC-NC-SA 3.0

This page most recently updated on June 6, 2020.