#12 - Poor nutrition is at the root of the violent behavior

[Administrator]

Complete Question Explanation

Strengthen—CE. The correct answer choice is (E)

Here the author presents a causal argument regarding a link between violence and nutrition, based on the results of a single experiment. Most violent offenders showed a preference for low-nutrient food, and the group that was given a high-nutrient diet instead showed a decrease in violence. The author concludes that this experiment confirms the link—this is a rather bold claim.

• Cause Effect
  
  better nutrition less violence

To strengthen this causal claim, we should seek the answer choice which confirms the link, or which rules out alternative explanations for the results of the referenced experiment.

Answer choice (E) is the correct answer choice, as it provides more reason to believe the author’s causal argument. We know from the stimulus that those who increased their nutrients decreased their violence. From this the author concludes that the nutrition was the cause. This answer choice provides that when the posited cause (better nutrition) was absent, the effect (lower violence) was absent as well. This strengthens the causal claim from the stimulus.

Answer choice (A) is irrelevant—“some” is quite vague, and regardless, we already knew that the subjects were violent.

Answer choice (B) is also completely irrelevant: the cost and ease of implementation have nothing to do with the validity of the author’s causal argument.

Answer choice (C) is also unhelpful—“a low-nutrient food” is very vague, the stimulus already provided that most subjects tended to choose low-nutrient foods when given the choice, and the stimulus discusses high- versus low-nutrient diets, not single food items.

Answer choice (D) provides that many youths who chose a high nutrition diet were non-violent. As far as the author's causal argument goes, this doesn't have much effect—that group has not become less violent, nor switched to higher nutrition (the study in the stimulus, on the other hand, dealt with violent offenders, who switched to higher nutrition, and then became less violent). Correct answer choice E deals with a group more relevant on many counts: they were violent inmates who continued with a low nutrition diet--basically the control group in the original study, which remained violent).

[tomoko]

Thank you so much for the answer!

[abajaj]

Hello,

I was part of the online live lecture course and I have a question regarding a Causality and Strengthen question in Lesson 4, Page 4-15, question #2. The topic of the question is regarding poor nutrition vs. violent behavior.

I am unable to understand why D is incorrect. I looked in the explanations online already and D isn't explained in there. I understand why E is correct, but I feel like D could strengthen the argument just as much. Is it because the stimulus talks about "violent behavior" and answer choice D talks about "nonviolent"?

Thank you!

[Dave Killoran]

Hi Aba,

The big problem with (D) is the shell game being played with the terms here, the one that you referred to in your comments about violent vs nonviolent. The stimulus refers to "the violent inmates among them [young offenders]" whereas this answer choice references the entire group of "young offenders." So, whereas the stimulus talks about violent going to nonviolent, we don't know that that result is what occurs in answer choice (D), and that difference opens a big hole in this answer. There's a further issue that could be raised about the fact that the offenders selected that diet on their own (self-selecting samples are a problem), but the first issue mentioned here is enough to kill (D) for us.

Please let me know if that helps. Thanks!

[netherlands]

Hi there PS,

I'm still can't seem to understand why answer choice D was better than E on this question. I see the causality - Poor Nutrition Violent Offenders

But both D and E seem to be super similar to me. Both seem to show Lack of Cause and Lack of Effect:

D) Chose High Nutrient Diet - Were nonviolent Offenders
E) Were not placed on high nutrient diet - Remained Violent Offenders

Am I attacking the wrong portion of the stimulus. I'm looking back and seeing that maybe since the conclusion focused on the results of the test - this it is irrelevant to choose an answer choice that refers to another study when answer choice "E" shows the lack of cause and lack of effect within the same study

Could you explain this further?

Thanks!

[Nikki Siclunov]

Netherlands,

The biggest problem in the study, as it is described in the stimulus, is the lack of a control group: we simply don't know if the behavior of those violent inmates who were not placed on a high-nutrient diet would have changed over time. Answer choice (E) fixes this problem by indicating that a control group would not have experienced the same reduction in violence as the test group.

As far as (D) is concerned, we don't know if the inmates in question were violent in the first place: they are described as "young offenders," and all we know is that those who chose high-nutrient diet were non-violent. Maybe they were never violent to begin with? What if those convicted of insider trading - the Martha Stewart type - are the ones choosing the high-nutrient diet? The fact that they chose the diet themselves in another issue: what if being a non-violent offender makes you more likely to choose better food? To strengthen the causal argument between nutrition and violence, we need to show some change in behavior that correlates with changes in one's diet, meanwhile eliminating (or reducing) the potential of other causes that might contribute to the same effect.

Does that make sense? Let me know.

Thanks!

[Blueballoon5%]

Hi! Could you elaborate on why answer choice C is wrong?

I think that, maybe, answer choice C is wrong because the argument in the stimulus is about behavioral improvement, while answer choice C only focuses on a single incident that could be linked to some types of food. Please let me know if this line of thinking is correct!

Also, I am unsure about the explanation above that "'a low-nutrient food' is very vague." Wouldn't the stimulus reference to high and low nutrient diets also be considered vague?

Thanks!!

[Claire Horan]

Hi BlueBalloon,

Thanks for the question. The original explanation in this thread is correct. Answer choice (C) is incorrect because knowing some of the offenders consumed a single low-nutrient food item does not strengthen the conclusion that the results of a study involving high- and low-nutrient diets confirm the link between poor nutrition and violent behavior. What the Administrator meant by vague is that it's unclear how it relates to the language in the stimulus. It's unclear how consuming "a low-nutrient food" relates to the person's diet. If that one food is all a person ate, that would be his diet. If the individual ate the low-nutrient food and several high-nutrient foods, she might have a high-nutrient diet overall. Labeling a diet "high-nutrient" or "low-nutrient" does not include much detail, but it is not vague in the same sense that it was being used in the Administrator's question explanation.

Now to address your idea about an alternative way to eliminate (C). It doesn't work and here is why. If you changed the "low-nutrient food" to "low-nutrient diet," then many of the offenders had a low-nutrient diet leading up to committing their crime. This would corroborate the results of the study that there is a link between poor nutrition and violent crime. So (C) would strengthen the conclusion if it referred to diet rather than single food items.

[martinbeslu]

Netherlands,

The biggest problem in the study, as it is described in the stimulus, is the lack of a control group: we simply don't know if the behavior of those violent inmates who were not placed on a high-nutrient diet would have changed over time. Answer choice (E) fixes this problem by indicating that a control group would not have experienced the same reduction in violence as the test group.

As far as (D) is concerned, we don't know if the inmates in question were violent in the first place: they are described as "young offenders," and all we know is that those who chose high-nutrient diet were non-violent. Maybe they were never violent to begin with? What if those convicted of insider trading - the Martha Stewart type - are the ones choosing the high-nutrient diet? The fact that they chose the diet themselves in another issue: what if being a non-violent offender makes you more likely to choose better food? To strengthen the causal argument between nutrition and violence, we need to show some change in behavior that correlates with changes in one's diet, meanwhile eliminating (or reducing) the potential of other causes that might contribute to the same effect.

Does that make sense? Let me know.

Thanks!

Hi Nikki,

I'm just joining this conversion but I had a question about your explanation for answer choice D. You said that we don't know if the inmates in question were violent in the first place. However, I thought the stimulus was saying that researchers observed violent inmates among the young offenders.

[Shannon Parker]

Netherlands,

The biggest problem in the study, as it is described in the stimulus, is the lack of a control group: we simply don't know if the behavior of those violent inmates who were not placed on a high-nutrient diet would have changed over time. Answer choice (E) fixes this problem by indicating that a control group would not have experienced the same reduction in violence as the test group.

As far as (D) is concerned, we don't know if the inmates in question were violent in the first place: they are described as "young offenders," and all we know is that those who chose high-nutrient diet were non-violent. Maybe they were never violent to begin with? What if those convicted of insider trading - the Martha Stewart type - are the ones choosing the high-nutrient diet? The fact that they chose the diet themselves in another issue: what if being a non-violent offender makes you more likely to choose better food? To strengthen the causal argument between nutrition and violence, we need to show some change in behavior that correlates with changes in one's diet, meanwhile eliminating (or reducing) the potential of other causes that might contribute to the same effect.

Does that make sense? Let me know.

Thanks!

Hi Nikki,

I'm just joining this conversion but I had a question about your explanation for answer choice D. You said that we don't know if the inmates in question were violent in the first place. However, I thought the stimulus was saying that researchers observed violent inmates among the young offenders.

Hi,

I believe that Nikki was referring specifically to the "young offenders" mentioned in answer choice D. Because we do not know if they were violent or not, there choice of a high-nutrient diet does not help to illustrate causation. Actually, the fact that you recognize that the stimulus is talking about violent offenders is a good tip for eliminating answer choice D. Because the stimulus talks about young violent offenders, and the answer choice just talks about young offenders, it is most likely a false equivalency.

Hope this clears it up.