Logical Reasoning

PT117 · S2 · Q20 Scientist: My research indicates that

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Scientist: My research indicates that children who engage in impulsive behavior similar to adult thrill-seeking behavior are twice as likely as other children to have a gene variant that increases sensitivity to dopamine.

Conclusion (I conclude that)

There is a causal relationship between this gene variant and an inclination toward thrill-seeking behavior.

Evidence

Children who engage in impulsive behavior (similar to adult thrill-seeking behavior) are twice as likely as other children to have a gene variant that increases sensitivity to dopamine.

Evaluate

The author presents a Correlation, , and then assumes a specific causal relationship. This looks like the ol' Explain a Curious Fact template.

Curious Fact ... why are impulsive children twice as likely to have variant X? Author's Explanation .... variant X causes the inclination toward thrill-seeking behavior.

The author actually just says "there is a causal relationship between the two", so technically she might think that being inclined toward thrill-seeking behavior causes this gene variant, but it's so beyond the realm of common sense to think that behavior would cause genetics that it feels natural to interpret this as "genetics causes the behavioral inclination".

The author's causal story also suggests that the variant makes someone more sensitive to dopamine, and that because these people feel so much from a release in dopamine, they get more out of thrill-seeking impulsivity (which presumably triggers a dopamine release).

Goal

Since this is Weaken, we'd be thinking we want either of these things:

1. to suggest an Alternate Explanation for the correlation between impulsive behavior and variant X

2. to undermine the plausibility of the author's explanation, which is that having this gene variant causes a bigger inclination to impulsive / thrill-seeking behavior.

20.

Which one of the following, if true, most calls into question the scientist's argument?

  1. Many impulsive adults are not

    Weak Impact

    This somewhat helps our case. This is sort of an Effect w/o Cause weakener. These people have impulsivity (which we're kind of equating with thrill-seeking) but don't have the unusual sensitivity to dopamine that people with the gene variant would have. However, the impact is very weak since "many" basically means "at least 5", so we're not learning about a ton of data points. And the author wasn't saying that "only people with this gene variant will be impulsive", just that having this gene variant increases your propensity towards impulsivity.

    15% picked this

  2. Correct

    It is not possible to

    Why this is right

    This weakens in a very unusual way -- it basically just suggests that the data upon which this argument is built is crappy data. If it's impossible to reliably distinguish impulsive behavior from other behavior, then the correlation this scientist thinks she found is basically junk data. She can tell whether or not each child has the gene variant, but there's no way to map that to whether or not the child engages in impulsive behavior, if there's no reliable way to distinguish impulsive behavior from other behavior. There are only a handful of problems ever in LR that weaken this way (attacking the premise as bad data), but it can happen. Here's another example if you want to see one.

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

    52% picked this

  3. Children are often described by

    No Impact

    This seems pretty consistent with the argument, which is saying that impulsive behavior in children is similar to adult thrill-seeking behavior. This answer isn't saying it's wrong to make that connection. It's just saying that adults often make use of that connection, describing an impulsively behaving child as one who is engaged in thrill-seeking behavior.

    10% picked this

  4. Many people exhibit behavioral tendencies

    Unclear Impact

    This is just so weak that we have no idea if it has any bearing on this conversation. At least five people have some behavioral tendency as an adult that they didn't have as a child? Okay. I can think of at least five adults who eat olives, now that they're adults, even though they didn't eat olives as children. Is that all this answer is talking about? This could only weaken the argument if we thought that the author was assuming, "If a behavior exists in adulthood, then that behavior existed in childhood", and we can't pin that assumption on this author.

    14% picked this

  5. The gene variant studied by

    Unclear Impact

    A gene variant could lead to several different inclinations or behaviors. A variant might make someone sweat more and make someone blink more often than most people. So what? If someone was pinpointing that gene variant as the cause of a person's frequent blinking, would it weaken to say, "No ... that gene variant also causes excess sweating?" This answer might have felt like a Third Factor answer. We have a correlation between this gene variant and impulsive/thrill-seeking behavior. Maybe the gene variant doesn't directly cause the impulsive behavior but instead causes some other behavior that then leads to impulsive behavior? However, that storyline isn't really going against the conclusion. The conclusion just says that there is a causal relationship between the gene variant and the impulsive behavior. The author doesn't specify whether it's a direct relationship or an indirect relationship, so if we used this answer to tell a story about an indirect relationship, we're still technically agreeing with the author's conclusion.

    11% picked this

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