LSAT Explanation PT 33, S1, Q1: Marmosets are the only primates other
LSAT Question Stem
Which one of the following, if true, most supports the researchers' hypothesis?
Logical Reasoning Question Type
This is a Strengthen question.
Correct Answer
The correct answer to this question is E.
LSAT Question Complete Explanation
First, let's analyze the argument in the passage. The passage states that marmosets are the only primates, other than humans, that display a preference for using one hand over the other. It also mentions that more marmosets are left-handed than right-handed. Researchers hypothesize that infant marmosets learn which hand to use through imitation, so offspring with left-handed parents generally share their parents' handedness. The structure of the argument is as follows:
Premise 1: Marmosets are the only primates other than humans known to display a preference for using one hand rather than the other.
Premise 2: Significantly more marmosets are left-handed than are right-handed.
Premise 3: Infant marmosets engage in much imitative behavior.
Conclusion: It is by imitation that infant marmosets learn which hand to use, so offspring reared by left-handed parents generally share their parents' handedness.
An "Evaluate" question for this argument could be: "Do marmosets raised by right-handed parents also tend to share their parents' handedness?"
Now let's discuss the question type and the answer choices. The question type is Strengthen, and it asks us to find the answer choice that most supports the researchers' hypothesis.
Answer choice (A): This answer choice states that many adult marmosets are right-handed. This doesn't support the researchers' hypothesis, as the question is why the majority are left-handed.
Answer choice (B): This answer choice suggests that right-handed marmosets have at least one left-handed sibling. While this could indicate that factors other than genetics play a role in determining handedness, it doesn't clearly support the hypothesis that imitative behavior is the cause.
Answer choice (C): This answer choice states that 33 percent of marmosets are ambidextrous. This doesn't help explain the preferences of the other 67 percent and has no effect on the causal relationship in the argument.
Answer choice (D): This answer choice discusses humans, not marmosets. It has no effect on the conclusion of the argument.
Answer choice (E): This is the correct answer choice. It states that marmosets raised in captivity with right-handed adult marmosets, to whom they are not related, are more likely to be right-handed than left-handed. Since the infant marmosets are not related to the right-handed adult marmosets, they couldn't have inherited their preference for using their right hand. This eliminates the most plausible alternate cause for marmosets' propensity to share their parents' handedness: whether related or not, the infants generally share the behavior of the adults.