Politician: A major social problem is children hurting other children. The results of a recent experiment by psychologists establish that watching violent films is at least partly responsible for this aggressive behavior. The psychologists conducted an experiment in which one group of children watched a film of people punching Bobo the Clown dolls. A second group of children was not shown the film. Afterward, both groups of children played together in a room containing a Bobo doll. Most of the children who had seen the film punched the Bobo doll, while most of the other children did not.
Summarize Argument: Phenomenon-Hypothesis
The politician hypothesizes that watching violent films contributes to the problem of children hurting other children. He supports this by citing a study where most children who saw a film of people punching a Bobo the Clown doll later punched the doll themselves, while those who didn't watch the film didn't punch it.
Notable Assumptions
The politician assumes that punching the Bobo doll is an accurate indicator of a child's tendency to hurt other children.
He also assumes that the study is representative and that its findings can be generalized to all children.
He also assumes that watching the film is the primary or sole cause of the children's behavior, ignoring other potential factors that could contribute to their behavior.
A
Some of the children who did not punch the Bobo doll, including some who had been shown the film, chastised those who did punch the doll.
Whether some of the children in each group chastised children who punched the doll doesn’t weaken the politician’s argument, which relies on the observation that most of the children who watched the film did punch the doll.
B
The child who punched the Bobo doll the hardest and the most frequently had not been shown the film.
Even if a child who didn't watch the film punched the doll the hardest, the fact remains that most children who watched the film did punch the doll, while most who didn't watch it did not. So (B) doesn’t weaken the politician's argument.
C
The children who had been shown the film were found to be no more likely than the children who had not been shown the film to punch other children.
The politician aims to address children hurting other children. For his conclusion to hold, he must assume that children who punch the doll will also hurt other children. But if children who watch the film are no more likely to punch other children, his argument falls apart.
D
Some children who had not been shown the film imitated the behavior of those who had been shown the film and who punched the doll.
Like (B), it doesn’t matter that some of the children who didn’t watch the film later punched the doll, because the politician’s argument relies on the fact that most children who watched the film did punch the doll, while most who didn't watch it did not.
E
Many of the children who participated in the experiment had never seen a Bobo doll before the experiment.
Whether the children had seen a Bobo doll before doesn’t change how the groups reacted to the doll after watching the film or not watching film.
Editorial: In order to encourage personal responsibility in adults, society should not restrict the performance of any of the actions of adults or interfere with the likely results except to prevent negative effects on others.
Summary
If a restriction on the action of adults is not implemented for the purpose of preventing negative effects on others, then a society should not implement that restriction.
Notable Valid Inferences
We are looking for something that is inconsistent with the principle. So we want an answer that involves society restricting the action of adults even though that restriction is implemented for a purpose besides preventing effects on others.
A
We should not prevent the students from wasting the classroom time set aside for homework. But this does not mean that they may spend the time any way they wish. Activities disruptive to others should not be tolerated.
Could be true. (A) recommends restricting activities disruptive to others. But that’s consistent with the principle, because it’s about preventing activities disruptive to others.
B
The scientist who invented this technology is not the only one who should be allowed to profit from it. After all, there is no evidence that allowing others to profit from this technology will reduce the scientist’s own profits.
Could be true. (B) doesn’t involve a restriction on someone’s actions. There’s no indication we’re stopping the scientist from performing an action. So the situation doesn’t contradict the principle.
C
Even though public smoking may lead to indirect harm to others, it should not be banned. There are several other ways to eliminate this harm that do not restrict the conduct of smokers and hence are preferable to a complete ban on public smoking.
Could be true. (C) recommends not banning public smoking. So this doesn’t involve an attempt to restrict actions; it allows actions. That means it can’t contradict the principle.
D
Highway speed limits are a justified restriction of freedom. For drivers who speed do not risk only their own lives; such drivers often injure or kill other people. Moreover, speed limits have been shown to significantly reduce highway accident and fatality rates.
Could be true. (D) recommends restricting actions because those actions can hurt others. To contradict the principle, we want a restriction that is NOT for the purpose of preventing harm to others.
E
It is not enough that consumable products containing harmful substances have warning labels. Many adults simply ignore such warnings and continue to consume these substances in spite of the harm it may cause them. This is why consuming such substances should be illegal.
Must be false. (E) recommends restricting actions (the consumption of the substances), even though the purpose of the restriction is to prevent harm to the person performing the action. In order to be acceptable, the restriction needs to be about preventing harm to OTHERS.
The goblin fern, which requires a thick layer of leaf litter on the forest floor, is disappearing from North American forests. In spots where it has recently vanished, the leaf litter is unusually thin and, unlike those places where this fern still thrives, is teeming with the European earthworm Lumbricus rubellus, which eats leaf litter. L. rubellus is thus probably responsible for the fern’s disappearance.
Summary
The author concludes that the L. rubellus worm is probably the cause of the goblin fern’s disappearance.
Why?
Because in spots where the fern has recently vanished, the leaf litter is unusually thin and teeming with L. rubellus worms. In places where the fern is still thriving, there aren’t as many L. Rubellus worms. L. Rubellus eats leaf litter.
Notable Assumptions
The premises establish a correlation between the fern’s disappearance and greater presence of L. Rubellus. The author assumes that the reason for this correlation is that L. Rubellus causes the fern to disappear. But that’s not the only explanation. Maybe the fern first disappears, and L. Rubellus is attracted in greater numbers to places where the fern has disappeared? Or maybe there’s some other cause that leads to both the fern’s disappearance and attracts the worm? The author assumes that these other explanations are not true.
A
Wherever there is a thick layer of leaf litter in North American forests, goblin ferns can be found.
The stimulus tells us that the fern requires a thick layer of leaf litter. But that doesn’t imply that anywhere there’s a thick layer of leaf litter, the fern will exist. Even if the fern sometimes doesn’t exist when there’s a thick layer, that doesn’t undermine the author’s reasoning.
B
None of the earthworms that are native to North America eat leaf litter.
Not necessary, because other earthworms can eat leaf litter. What matters is that we’ve seen a correlation between fern disappearance and the L. Rubellus. The author does have to assume that there isn’t a similar correlation observed with other worms; but that doesn’t mean the author thinks no other worms eat leaf litter.
C
Dead leaves from goblin ferns make up the greater part of the layer of leaf litter on the forest floors where the goblin fern has recently vanished.
Not necessary, because even if dead leaves from the ferns are less than half of the leaf litter layer, that doesn’t undermine the author’s reasoning. Perhaps there are many other plants in the area that also make leaf litter, and that’s why the leaf litter could be mostly other plants, not the fern.
D
There are no spots in the forests of North America where both goblin ferns and earthworms of the species L. rubellus can be found.
Not necessary, because the fern could be in the process of disappearing in some places. If it turns out that there are some spots where we find both the ferns and the worms, it could just mean that the worms are in the process of eating leaf litter and the ferns will die soon. This is completely consistent with the author’s reasoning.
E
L. rubellus does not favor habitats where the leaf litter layer is considerably thinner than what is required by goblin ferns.
Necessary, because if it were not true — if the worm DOES favor habitats where the leaf litter is considerably thinner than that required by goblin ferns — that could be the true explanation for the presence of the worm in areas where the fern has disappeared. It’s not that the worm eats the leaf litter, which then causes the ferns to die — it could be that the leaf litter is already thin, which causes the ferns to die, and the worms show up after the leaf litter is thin.