Logical reasoning PrepTest 152 · Section 2 · Question 23

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Researchers in masks kidnapped crows and then released them. Years later, the crows were still afraid of masks. Therefore, crows can recognize threats and warn other crows.

Answer Anticipation:
There are two big flaws in this argument—both related to the way the experiment was run.

First, the conclusion here is causal, but it's based on a correlation (the crows shrieked at people/attacked them, and those people were wearing masks). That correlation/causation jump has the normal issues associated with it, but, in particular, this experiment lends itself to another explanation—crows shriek at and attack anyone near them. There's no control here—showing that when the cause is absent, so is the effect.

Second, there's a sampling flaw—but a different one than you might expect. The argument concludes that crows can both recognize threatening people and communicate that to others. In order to prove that conclusion, the sample of crows here years later must include both some original crows (to establish they recognize people) and new crows (to establish the original crows can communicate this threat).

The argument requires both of these issues to be addressed, so either individually is a necessary premise we can look for in the answers.

Answer Explanation:
This answer deals with the sampling issue that we spotted. If all of the crows that were spotted years later were the same crows, there's no evidence of communication between the crows and thus that part of the conclusion falls apart.

Key Takeaway:
Studies tend to conclude causality, and thus they generally have correlation/causation flaws. They also always have a sample of some type, so they lend themselves to sampling flaws, as well. Really digging in during review to see how studies on the LSAT end up leading to flawed conclusions can help you quickly spot issues—and when there are multiple issues—on questions featuring studies, of which there are many.

Incorrect. This answer is too strong. The argument doesn't require crows that perceive someone as threatening to always shriek and dive-bomb them—it just requires that they in some way respond to them to demonstrate they view them as threatening. The argument relies on shrieking and dive-bombing being a response to threatening people, but not the only one.

Incorrect. The argument is about crows, so an answer about "most birds of any species" isn't necessary to make it work.

Incorrect. This answer deals with the correlation/causation flaw we spotted. However, it weakens the argument by pointing out that the crows didn't recognize these people from years before and communicated that fear, but rather that they always respond to masked individuals by shrieking and attacking.

Incorrect. The argument does rely on the crows being able to recognize those in caveman masks as different and threatening, but it doesn't require them to lack the ability to recognize individual human faces. That's out of scope, so not necessary.