Logical ReasoningDifficulty: Hard

PT158 S2 Q15 ExplanationPsychologist: We measured the

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

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Stimulus

Psychologist: We measured the "cognitive plasticity," or the willingness to accept new ideas, of a group of people of both genders and of all ages. The first-born children in the study consistently exhibited less cognitive plasticity than did their siblings. It is reasonable to think that those who are open to new first-born children will tend to be more adventurous than will the first-borns.

What this question is testing

Strengthen

Conclusion

Later-born siblings are the adventurous ones in the family — more likely to take risks and explore than their cautious, tradition-bound older siblings.

Evidence

The study found that first-borns are less willing to accept new ideas than their younger siblings. The psychologist then takes a leap: being open to new ideas probably means being adventurous in general.

Assumption

The psychologist measured one thing (willingness to consider new ideas) and predicted another (adventurous behavior). That is like measuring how much someone likes trying new restaurants and concluding they would probably go skydiving. It is "reasonable to think" the two go together, but reasonable speculation is not evidence. The argument needs something to nail down that connection.

Goal

Find the answer that provides actual evidence — not just wishful thinking — that people who are open to new ideas also tend to be adventurous in their actions.

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The question
15.

Which one of the following, if true, most strengthens the

Answer choices, explained

  1. Weakens, If Anything1% picked this

    Some of the great creative geniuses in history were

    The existence of creative first-born geniuses, if anything, undermines the argument's conclusion rather than supporting it. The argument claims first-borns are less cognitively plastic and therefore less adventurous. Examples of highly creative first-borns suggest that the cognitive plasticity findings may not generalize as broadly as the psychologist claims, or that cognitive plasticity and creative genius are not as tightly linked as assumed. Moreover, "some great creative geniuses" is anecdotal evidence that does not establish a general pattern. It provides isolated counterexamples to the study's findings without supporting the bridge between cognitive plasticity and adventurousness. This pushes against the argument rather than strengthening it.

  2. Weakens16% picked this

    In most cases, the more younger siblings one has, the greater

    This answer actually undermines the argument. If having more younger siblings increases cognitive plasticity, then the study's results could be confounded by family size rather than birth order per se. A first-born in a family of two might have only slightly less cognitive plasticity than their one sibling, while a first-born in a family of six would appear dramatically less plastic compared to siblings who benefit from having many younger peers. This suggests the relationship between birth order and cognitive plasticity is more nuanced than the psychologist presents, and the clean first-born-versus-sibling distinction may be an artifact of family size. Rather than strengthening the bridge to adventurousness, this answer complicates the underlying evidence.

  3. Correct65% picked this

    Other studies have shown a correlation between cognitive plasticity and the willingness

    Why this is right

    The argument's weakest link is the bridge from cognitive plasticity (willingness to accept new ideas) to adventurousness (willingness to take risks in behavior). The psychologist stated this connection as merely "reasonable to think" — an assertion without evidence. This answer provides exactly that missing evidence. If other studies have independently demonstrated a correlation between cognitive plasticity and willingness to take risks, the bridge is no longer speculation; it is empirically supported. The strengthening works in two steps: first, the study shows siblings have more cognitive plasticity than first-borns; second, this answer confirms that cognitive plasticity correlates with risk-taking (a form of adventurousness). Together, these make the conclusion — that siblings tend to be more adventurous — substantially more credible. This is the only answer that directly supports the inferential gap between the measured trait and the predicted behavior.

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

  4. Too Weak15% picked this

    A study of business executives shows that several industry leaders have

    A study of business executives showing that "several" industry leaders have older siblings is too limited and too narrow to meaningfully strengthen the argument. First, "several" is a vague, small number that does not establish a pattern. Second, business executives are a specific subset of the population, and leadership in business may not reflect adventurousness generally. Third, having older siblings makes someone a non-first-born, but the observation that some non-first-borns became leaders does not establish the cognitive plasticity-to-adventurousness link the argument needs. The evidence is anecdotal, narrowly drawn, and does not directly support the bridge between measured openness and predicted behavior. A few data points from one industry cannot carry the weight of a general behavioral conclusion.

  5. No Impact3% picked this

    Most of the participants in the study had characterized themselves as more adaptable

    How participants characterized themselves before the study began is irrelevant to whether cognitive plasticity actually correlates with adventurousness. Self-assessment of adaptability is not the same as measured cognitive plasticity, and people's beliefs about their own traits do not validate the bridge between openness-to-ideas and adventurous behavior. Moreover, the fact that most participants thought they were more adaptable than their siblings is a universal self-flattery bias that tells us nothing about actual behavior. The argument needs objective evidence linking cognitive plasticity to adventurousness; subjective self-assessments from participants provide neither the objectivity nor the specificity required.

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