PrepTest 143, Section 1, Question 20
Researchers compared the brains of recently deceased people(70 more words not shown)
Which one of the following(9 more words not shown)
- ARoughly 35 percent(10 more words not shown)
- BA promising treatment(18 more words not shown)
- CSome people developed(13 more words not shown)
- DSchizophrenia is determined(3 more words not shown)
- EThere may be(7 more words not shown)
Reading the argument
The damage happened before birth. That makes the timing worth paying attention to.
First, keep the two groups straight. Subplate damage appeared in 35 percent of the examined brains from people who had schizophrenia, and in none from those who didn't. That gives us an association. By itself, it doesn't tell us whether the damage caused schizophrenia or whether some other factor contributed to both.
Now add the timing: the damage must have occurred before the second fetal trimester. So at least one feature associated with schizophrenia was already present during development before birth. That suggests a possible early cause worth investigating. It doesn't establish exactly what that cause is.
What we’re looking for
The question asks what is most strongly supported. I'd look for a cautious conclusion about a possible influence before birth, rather than a definite claim that this damage or a particular gene causes the condition.
Working the answers
- A
The 35 percent goes the other way. It describes how many people in the schizophrenia group had subplate damage. It doesn't tell us what percentage of all people with abnormal subplates will develop schizophrenia. Changing which group supplies the starting population changes the statistic.
- B
We have no evidence about repairing the damage or about the effects of doing so. Even if an early injury contributed to later problems, that wouldn't by itself establish that repairing connections later would be a promising treatment. B adds an intervention the study never examined.
- C
The timing is wrong: the described damage occurred before the second fetal trimester, while C says after. C also claims that the damage caused schizophrenia, which the association doesn't establish. A different factor could have contributed to both the damage and the condition.
- D
Before birth doesn't mean genetic. Something affecting development could be environmental rather than inherited. The study doesn't identify genes as the cause, so D states a particular explanation we haven't established.
- ECorrect
There may be a cause that predates birth. The prenatal timing of damage associated with schizophrenia supports investigating that possibility. Notice the modest wording: “may be.” E doesn't settle whether the damage itself is causal or whether another early factor helps explain both findings. It stays within what the evidence suggests.
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