#22 - No one knows what purposes, if any, dreams serve

[Administrator]

Complete Question Explanation

Must Be True. The correct answer choice is (C)

The hypothesis itself has two steps: (1) parasitic connections "would otherwise clog up our memories" and (2) dreaming is how your brain gets rid of parasitic connections. So, if you do not dream, you do not get rid of parasitic connections, and those connections clog up our memories.

Pay close attention to the question stem here: it asks what is most strongly supported by the hypothesis, not the entire stimulus. The correct answer choice, then, will depend directly on the hypothesis.

Answer choice (A) does not follow from the hypothesis, because we are concerned with time spent dreaming, not sleeping – it is possible that small animals spend less time sleeping, but more of that time dreaming. Or, maybe they do not get many parasitic connections that need to be cleared out.

Answer choice (B) assumes that dreaming clears away nearly all parasitic connections. But, the hypothesis only assumes that some are cleared away.

Answer Choice (C), the correct answer, addresses this directly: mammals that are prevented from dreaming have clogged up memories. Students often reply with "But, what about the spiny anteater – it does not dream at all." However, the answer choice is limited to mammals "that would normally dream" – it specifically excludes the anteater.

Answer choice (D) is tricky: it is likely to be correct, but does not necessarily follow from the hypothesis. Remember what the question stem is looking for.

Answer choice (E), like (D), might be correct, but does not necessarily follow from the hypothesis. In addition, it goes a little too far: we think the only mammal that does not dream is the spiny anteater. But, the stimulus says nothing about lizards or other non-mammals.

[MBG13]

I initially wanted to write a reply to this because while I understood why choice (C) was correct, I couldn't understand why choice (B) was wrong and the explanation for why B was wrong did not seem right to me.

But in formulating my question, I had an AHA moment

I believe (B) is wrong because it assumes that when "a person awakens from normal sleep," the individual dreamt which is the necessary for erasing parasitic connections.

I initially wrote the facts like logical chain:

~Dream --> ~Erase PC --> Clog Memory

In the end, even with my logical chain, I failed to see that "functioning of its memory will be impaired" is the same as "clog up our memories"

[Adam Tyson]

Hey MBG, I think you've raised a good point that our explanation did not take into account. B talks about "normal sleep", and assumes without any justification that normal sleep requires dreaming and therefore erasing of those parasitic connections. The stimulus doesn't tell us about normal sleep, just about dreaming, so I think you're correct and you have found yet another reason to reject answer B. Still, our explanation also covers it - there's no proof that dreaming erases ALL of the connections, or even most of them, just some of them.

Take a look at the stimulus again, and notice the bit about having an effective memory - to have that you have to either dream (and erase connections that clog memory) or else have a larger brain like the anteater. That should be enough to make the short leap from "clogged memory" to "impaired functioning". Maybe even that isn't required - a "clog" already has a negative connotation and means blocking or impairing something, right?

Good work! I love to see new approaches that supplement ours!

[co659]

Hello ! I'm still confused by the above explanation as to why answer choice (B) is not correct. Maybe I am mis-reading the stimulus but I cannot find the line that distinguishes that only "some" parasitic connections are erased. I see the following:

According to one hypothesis, dreams are produced when the brain is erasing "parasitic connections" (meaningless, -accidental associations between ideas), which accumulate during the day and which would otherwise clog up our memories.

[Jonathan Evans]

Hi, Co659.

Good question! Let's return to the question stem to assess our task here:

• The parasitic-connection hypothesis, if true, most strongly supports which one of the following?

We can observe a couple points here:

1. Accept that the parasitic-connection hypothesis is true.
2. This hypothesis and the other information in the stimulus most strongly supports which answer?

To wit, we need to know which among the answer choices has the most support. Given that:

1. According to the parasitic-connection hypothesis, unaddressed "parasitic connections" would "clog up our memories" AND
2. Dreaming erases "parasitic connections"

It follows that without dreaming, parasitic connections would remain, and these connections in turn would clog up (impair) memory.

Thus we have direct, strong support for Answer Choice (C). Now let's consider Answer Choice (B). While we would still know that

• According to the parasitic-connection hypothesis, dreaming erases "parasitic connections,"

We do not have evidence to suggest that dreaming erases ALL "parasitic connections." It is possible that dreaming erases all parasitic connections. It is also possible that dreaming has erased not all parasitic connections. Either scenario is possible given the information in the stimulus. Thus, Answer Choice (B) presents a scenario that could be true, but remember on Must Be True questions we must either prefer an answer with incontrovertible evidence or pick the answer that is most strongly supported. In this case, Answer Choice (C) has stronger support than has Answer Choice (B).

I hope this helps!

[martinbeslu]

Answer D seems like it has to be the answer most strongly supported by the parasitic-connection hypothesis. The hypothesis states that dreams are produced when the brain is erasing meaningless accidental associations between ideas. Therefore, if a person describes a dream that has meaningful associations, then it cannot be an accurate description. This seems like a rock solid statement based directly on the exact wording of the hypothesis.

[Jonathan Evans]

Hi, Martinbeslu,

Good question. In fact, based on the statements in the stimulus, the "parasitic-connection hypothesis" suggests that dreams occur when the brain is erasing "meaningless, accidental associations between ideas." This statement need not lead to the inference that dreams consist entirely of "meaningless, accidental associations;" it is consistent with this statement to suggest that dreams may consist in part of "meaningless, accidental associations" and in part of "meaningful associations." In fact, there is no statement in the stimulus at all that suggests that "meaningless, accidental associations" need be present at all within dreams. This is certainly a plausible statement but is not directly addressed within the stimulus.

Thus, there is actually not support for the statement that descriptions of dreams involving meaningful associations of ideas need be inaccurate.

I hope this helps!

[nlittle]

I chose correctly as it was the least bad answer, however, I don't feel like we can justify using the word impaired as it seems like a relative term. You're memory may not be impaired when compared to when you had fallen asleep, but instead be just the same..

[James Finch]

Hi N,

This question is presupposing the hypothesis about the connection between dreams and memory is true. According to the hypothesis, dreaming is required for memory to function well (not be clogged up), so if an animal is dream-deprived, then its memory wouldn't work well, ie it would be impaired.

Hope this helps!

[martinbeslu]

Wow, that was a tricky one. This is all starting to make more sense. Thanks Jonathan