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Match principles | Video lesson

Watch a demonstration of one way to approach a question that asks you to identify a statement that reflects a principle from the passage on the Logical Reasoning section of the LSAT.

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  • blobby green style avatar for user Chesterfeedme
    How does choice C match the principle? Why are we to assume that noxious fumes impair the judgement or ability of the workers? Could the fumes not simply be dangerous, and not necessarily impair the judgement of the worker?
    (5 votes)
    Default Khan Academy avatar avatar for user
    • mr pink red style avatar for user Alex Wong
      I think the instructor inferred that the thing affecting people (sleep deprivation, noxious fumes, etc.) was causing them not to realize how that thing was affecting them, but I don't believe this is a relationship we can infer. I'd state the principle more generally: "people are not always the best judges of how things are affecting them."
      (2 votes)

Video transcript

- [Instructor] To identify the question let's look at what it asks. Each of the following illustrates the principle that the passage illustrates except. This is a match the principles question. The twist here is that it's also an except question, which means that the four wrong choices will be situations that share a principle with the passage and that the answer will be a situation that doesn't share a principle with the passage. A principle is a sort of general rule or generalization that governs a specific situation. One example of a common everyday principle that you might be familiar with is absence makes the heart grow fonder. So a situation that conforms to that principle might be something like, Alexandra stayed angry at her friends until she moved away and then she could only remember the good things about their friendship. And then a situation with a matching principle might be something like, David never got along with his brother until they lived in separate houses and didn't see each other very much then they became very close. See how we have two specific situations that contain the same principle. That's what we're looking for when we match the principles. So pause your video now if you wanna try this question on your own otherwise we will move to the explanation. All right, let's read this passage together and we'll pay attention to what kind of principle might be at play. The passage reads, when drivers are deprived of sleep there are definite behavioral changes, such as slower responses to stimuli and a reduced ability to concentrate, but people's self-awareness of these changes is poor. Most drivers think they can tell when they are about to fall asleep, but they cannot. So here we have a situation. There's no argument, there's no strong opinion, we just have some information about drivers. It seems like a key point here is the discrepancy between what driver's think is happening and what's really happening, in this specific instance of when drivers are deprived of sleep. So, drivers don't have enough sleep. And then they experience behavioral changes but don't realize that they're experiencing those changes. So they believe they'll be able to tell when they're about to fall asleep but they actually can't. And then the reason they can't is because they're sleep deprived. You see the issue here. They're so sleep deprived that they aren't equipped to tell if they're going to fall asleep. So if we were to phrase a general statement that illustrates what's being described here, it might be something like, sometimes people's physical conditions cause them to not be able to make good decisions. It doesn't have to be precise. And in fact principles are usually very general. Now remember that we're working with an except question. That means that four of the choices will have the same principle and one won't. So let's evaluate each choice to see which one gives us a situation that doesn't illustrate the principle we just saw. A, people who have been drinking alcohol are not good judges of whether they are too drunk to drive. This illustrates the same principle we just saw in the passage. People have been drinking alcohol and that alcohol is actually the precise reason they can't tell if they're too drunk to drive. That's a match, so we can eliminate this choice. B, elementary school students who dislike arithmetic are not good judges of whether multiplication tables should be included in the school's curriculum. So this doesn't match the principle that we saw in the passage. There's no physical condition that's preventing the students from being able to do something. It's just that these students are biased by their dislike of something. So they're too biased to be considered good, reasonable judges of what should be in the school's curriculum. Since this situations principle doesn't match the passages principle and we're working with an except question, that means that this is our answer. We could select it and move on, on test day if we feel confident, and we would save ourselves a lot of trouble and time. Let's look at the remaining choices now in case you have questions on them. C, industrial workers who have just been exposed to noxious fumes are not good judges of whether they should keep working. This is a beautiful match for the passages situation. We have a physical condition, and that's being exposed to noxious fumes. And then that physical condition is exactly what's causing the workers to not be good judges of whether they should keep working. The fumes are impairing the workers decision making abilities. D, people who have just donated blood and have become faint are not good judges of whether they are ready to walk out of the facility. This choice also has a matching principle. The physical condition is of being faint from donating blood, and their good decision is about whether they're ready to walk out of the facility. And the physical condition is stopping them from being able to make a good decision. E, people who are being treated for schizophrenia are not good judges of whether they should continue their medical treatments. And this is our final matching principle. The physical condition is schizophrenia. And it's physically preventing people from being able to make a good decision about whether they should continue their medical treatments. So to recap, for match the principle questions it's a good idea to determine what principle governs the passage. And then you should be able to identify the choice that illustrates that same principle. Or in this case, since we had an except question, eliminate the choices that illustrate that same principle. The stronger your notion of a principle is the easier it usually is to find the situation that has that same principle.