PrepTest 154

Incorrect. This could be true, but it also could be false according to the stimulus. Nothing there gives us any indication there were any other responses observed. Something that could be true or could be false is always incorrect for a must be true question.

Incorrect. Again, this is tempting because it sounds like it's probably true in the real world. We can't have a whole brain part JUST for sensing fear, can we? But the objective is to find what this stimulus most strongly supports, not what we could most easily prove on Google. The premises given don't tell us about any other function for the amygdala, so this could be false.

Incorrect. This is just wildly out of scope. We're talking about fear in people who've had their amygdalas destroyed by one disease. Nothing in the premises supports any inferences about other diseases.

Incorrect. Even if this was true, how would it be relevant to the premises we've been given? A conclusion must be supported by at least one premise, and none of those given in the stimulus directly supports this answer choice.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
The amygdala is one part of the brain involved in fear. People with a certain condition that destroys the amygdala are mostly fearless, but if they are given a breath high in carbon dioxide, they experience the same extreme fear that people with typical amygdalae do. This sounds like a pretty sadistic experiment (and how do you "give" someone a breath?) but that's just what we're dealing with here.

Answer Anticipation:
Sounds like there's something going on with fear responses besides a reaction from the amygdala, doesn't it? "Destroys" is a very strong word to use, so the amygdala is probably not intact enough in these people to be responsible for their fear when exposed to carbon dioxide. This is a "most strongly supported" must be true, so we'd like to find something that suggests the amygdala isn't alone in triggering fear, but nothing so strong that it can't be supported by these premises alone.

Answer Explanation:
Here we go. If people with a destroyed amygdala can experience fear, it must be not only the amygdala that produces a fear response. Notice the weak language: "not the only" and "can" both make this a very tepid conclusion, perfect for a "most strongly supported" prompt.

Key Takeaway:
It's easier to do Must Be True questions when you keep in mind that you're drawing a conclusion from the stimulus, and that conclusions are only valid if they follow directly from the premise(s). This rule will help you stay away from tempting incorrect answers that are most likely true in reality, but not proven by the stimulus.