Logical reasoning PrepTest 145 · Section 2 · Question 4

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
1980 Ð The northern cardinal is rare in Nova Scotia (outside the northern range)
2000 Ð The northern cardinal is common in Nova Scotia
1980-2000 Ð Winter temperatures rose slightly
Therefore Ð The warmer winter temps probably cause the northern cardinal to move to Nova Scotia

Answer Anticipation:
A Weaken question with a causal conclusion? Yes, please! These generally feature correlation/causation flaws, and we have set answer choices that we can look for when that's the case.

Here, the conclusion is based on a correlation—birds moved to an area and "over that period" the average winter temperature increased.

Since this Weaken question features a correlation/causation flaw, we should look for an answer that:

(1) Identifies an alternative cause
(2) Raises a counterexample (cause without effect; effect without cause)
(3) Suggests reverse causality (unlikely here, as birds moving to Nova Scotia probably didn't increase the temperature)

Answer Explanation:
This answer identifies an alternative cause. Bird feeders/an easy source of food could have attracted the birds, not the warm winter climate. In identifying an alternative cause, this answer weakens the argument.

Key Takeaway:
Weaken questions frequently feature correlation/causation flaws, and when they do, we have common answer patterns that we should look out for. Knowing these patterns can really cut down on our time and increase our accuracy on these questions.

Incorrect. If anything, this suggests that observations in 1980 and 2000 were probably pretty accurate since the birds are hard to miss seeing.

Incorrect. Assuming this answer means "in Nova Scotia" (which is a pretty big thing to forget to state, suggesting it's a wrong answer), this answer doesn't address why they moved there, so it doesn't weaken an argument about why the northern cardinals moved there.

Incorrect. The northern cardinal is a nonmigratory bird, so their population fluctuated more during this period than migratory birds. But that doesn't affect the argument. Fluctuating "more" could still be a relatively low level of fluctuation—if migratory bird populations fluctuated .5%, the nonmigratory bird populations could have fluctuated .7%. And it still doesn't address why they moved to Nova Scotia, so it doesn't weaken an argument that answers that question.

Incorrect. If anything, this suggests that the northern cardinal population must have increased even more than the population would suggest since more are ending up prey to the higher level of predators.