Logical ReasoningDifficulty: Medium

PT105 S2 Q12 Explanation

It is probably not true that colic

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsWeaken

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Stimulus

It is probably not true that colic in infants is caused by the inability of those infants to tolerate certain antibodies found in cow’s milk, since it is often the case that symptoms that are fed breast milk exclusively.

What this question is testing

Weaken

Your task

Find the choice that makes the argument's conclusion less likely to be true.

Common trap

Answers that look negative but attack a claim the argument never relied on.

Winning move

Find the assumption the argument depends on, then pick the choice that undermines it.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
12.

Which one of the following, if true, most seriously weakens

Answer choices

  1. Strengthens, If Anything1% picked this

    A study involving 500 sets of twins has found that if one infant has colic, its twin will

    This makes it sound like colic is genetically based (if your twin also has it). It doesn't give us a way to say that it's caused by cow's milk antibodies.

  2. Strengthens6% picked this

    Symptoms of colic generally disappear as infants grow older, whether the infants have been fed breast milk exclusively or have been fed

    This makes it sound like breast milk vs. cow's milk makes no real difference on colic disappearing, which helps the author argue that colic was never about the type of milk in the first place. An answer that said, "When they stopped cow's milk, the colic went away" would make it sound like cow's milk was the cause of the colic. But since this is saying, "When they stop breast or cow's milk, the colic eventually goes away" doesn't allow us to blame the cow.

  3. Strengthens6% picked this

    In a study of 5,000 infants who were fed only infant formula containing cow’s milk, over 4,000 of the infants never

    Over 4/5 of the infants didn't get colic, even though they were drinking cow's milk. That strengthens the idea that cow's milk isn't causing colic.

  4. Correct76% picked this

    When mothers of infants that are fed only breast milk eliminate cow’s milk and all products made from cow’s milk from their own diets,

    Why this is right

    This allows us to argue that "cow's milk causes colic". We were trying to solve the mystery of how exclusively breast-fed babies still got colic, and it sounds like the cow's milk that the Mama drinks can get into the breastmilk. After all, once Mama ditched all cow's milk, those breastfed babies saw their colic disappear.

    Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

  5. No Impact11% picked this

    Infants that are fed breast milk develop mature digestive systems at an earlier age than do those that are fed infant formulas, and infants

    If breast milk leads to digestive maturity, and digestive maturity helps you tolerate antibodies in cow's milk, then kids who drink breast milk would be less likely to get colic (if colic is actually caused by antibodies in cow's milk). But we don't know if colic is caused by cow's milk antibodies, and this answer choice isn't giving us any information that helps us assess what colic is caused by (in fact, this answer doesn't mention colic at all).

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