Logical reasoning PrepTest 134 · Section 2 · Question 20

Incorrect. The scope of the conclusion is limited to the influence of the amygdala and cortex on each other, so influence over other parts of the brain is out of scope.

Incorrect. Similar to (A), the scope of the conclusion is limited to the influence of the amygdala and cortex on each other, so influence over other parts of the brain is out of scope.

Incorrect. First, this answer doesn't establish that the level of development is related to the influence, just that the two are correlated in one situation. Therefore, since this answer doesn't establish that the region in question is the amygdala, we can't extrapolate about the influence the amygdala has based on this connection. Second, even if the amygdala is this region, that doesn't tell us anything about the level of influence the cortex has on the amygdala, thus this answer can't justify the comparison in the conclusion.

Incorrect. While this answer might show that other areas of the brain have influence over the cortex, that's out of scope of an argument comparing the influence of two areas of the brain over each other. Similar to (A) and (B), answers about other areas of the brain are out of scope.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
Cortex→Amygdala neural connections are less developed than Amygdala→Cortex connections. Therefore, the amygdala influences the cortex more than the reverse.

Answer Anticipation:
Don't get lost in those definitions of what the two areas of the brain do! This question isn't about science; it's about logic.

As in most Strengthen with Sufficient Premise questions, there's a new concept in the conclusion that doesn't show up in the premises—influence. When there's a new term, it needs to be connected to something from the premises.

Here, the argument concludes that the amygdala has more influence over the cortex. Why does it feel it can draw this comparison? Because the neural connections that go from the amygdala to the cortex are more developed than those that go in the other direction.

That comparison connects the premise to the conclusion, so we need to connect these concepts that are a part of the mirrored comparisons: more developed neural connections allow for a larger influence to be exerted.

Answer Explanation:
This answer establishes that the premise about neural connection development can support a conclusion about influence. Since the argument treats greater development as determining influence, this answer which establishes the former is directly proportional to the latter allows the conclusion here to be drawn. This is therefore the correct answer.

Key Takeaway:
Look for new concepts in the conclusion of Strengthen with Sufficient Premise questions—the correct answer will connect an idea from the premise to that new concept. Arguments must establish something in the premises about all key terms that show up in the conclusion—otherwise, there's no justification for that conclusion.