PrepTest 129

Incorrect. As long as these bees have larger brains than the ones that tend to the baby bees, the argument still works just fine. The stimulus isn't that foraging continually leads to brain growth, but that foraging leads to increased brain size—it might cause the brain to grow a bit and then stop.

Incorrect. Without knowing if these other responsibilities can maintain a larger brain size, or that brain size even can shrink, this answer doesn't have an effect on the argument.

Incorrect. The stimulus doesn't suggest nor does it rely on distance traveled being related to brain size, just whether a bee forages or not, so this answer is out of scope.

Incorrect. Marginally larger is still larger, and "some species" of bee isn't enough to undermine a probabilistic argument ("usually", "tend to").

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Older bees—Foragers, bigger brains
Younger bees—Babysitters, smaller brains
Foraging requires more smarts than babysitting
Therefore: Foraging caused brains to grow

Answer Anticipation:
Weaken questions frequently—if not usually—feature correlation/causation jumps. Here, the conclusion is certainly causal ("leads to"), so we should check the premises to see if they're correlations.

And they are! Older bees "usually" forage and "tend to" have larger brains. Those aren't causal statements, they're correlations. So this argument is jumping from correlation to causation. As such, our common correlation/causation answers in Weaken questions are in play: ID an alternative cause; counterexamples (cause without effect/effect without cause); reversed causality (brain growth leads to foraging behavior, which isn't outlandish). In particular, the argument itself brings up a potential alternative cause—age! Maybe bee brains just get bigger over time.

Note that there is a premise that connects foraging to cognitive ability. However, first, there's no indication that brain size is related to cognitive ability, or that bigger brains can handle a larger cognitive load—maybe bigger brains are inefficient! It also only establishes that a greater cognitive ability is needed for foraging compared to babysitting—but that leaves open the possibility that all bees have the ability to forage, but that not all of them use their full cognitive abilities.

Answer Explanation:
This answer choice brings up a counterexample—bees that have the effect (bigger brains) without the supposed cause (foraging), thus suggesting an alternative cause—in this case, bee brains get older as they age, not as they engage in any particular activity!

Key Takeaway:
By far, the most common flaw in Weaken questions is a jump from correlation to causation. Be on the lookout for it, both by reading premises with an eye for correlation phrases and by reading the conclusion with an eye for causal language.