LSAT 117 | Section 4 | Logical Reasoning: Q14

LR Question 14 Explanation

QUESTION TEXT: Scientists hypothesize that a particular type of fat …

QUESTION TYPE: Strengthen

CONCLUSION: P-fat is required for the development of eyesight.

REASONING:

• Babies fed formulas low in P-fat tend to have worse eyesight than babies fed mother’s milk, which is high in P-fat.
• Premature babies also tend to have worse eyesight.

ANALYSIS: The first observation is pretty straightforward: Less P-fat → worse eyesight.

The second observation about premature babies is pretty weak. It just says premature babies tend to have worse eyesight than full-term babies.

If we want that evidence to help the hypothesis, we need to connect prematurity and lower exposure to P-fat.

If premature babies miss out on receiving P-fat that full-term babies normally get, then both pieces of evidence point to the same conclusion:

1. Babies receiving little P-fat through formula have worse eyesight.
2. Premature babies also receive less P-fat and have worse eyesight.

Now the two observations reinforce each other and both support the conclusion that P-fat is required for the development of eyesight.

___________

1. This concerns adults, not the development of eyesight in babies. P-fat may be necessary during development but not for maintaining eyesight in adulthood.
2. CORRECT. If fetuses receive high levels of P-fat only during the last four weeks of pregnancy, then babies born five to six weeks early miss out on that P-fat. So premature babies → less P-fat → worse eyesight. Now both of the observations support the conclusion.
3. This rules out an alternative explanation (genetics). But that doesn’t necessarily help strengthen the P-fat hypothesis. It could be something other than P-fat and genetics.
4. Babies’ taste preferences have nothing to do with whether P-fat is necessary for eyesight development.
5. This tells us when eyesight develops, but it says nothing about whether P-fat is involved in that development. In fact, if eyesight development is largely completed before birth, then the scientists’ observation that babies fed low-P-fat formula have worse eyesight becomes harder to explain, because those postnatal differences in P-fat intake may be irrelevant to eyesight development altogether.