Reading Comprehension

PT132 · S1 · P3 · Q21 Dental Caries

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Passage A Because dental caries (decay) is strongly linked to consumption of the sticky, carbohydrate-rich staples of agricultural diets, prehistoric human teeth can provide clues about when a population made the transition from a hunter-gatherer diet to an agricultural one.

Topic

The relationship between dental caries (cavities) and carbohydrate consumption — used as a clue to the transition from hunter-gatherer to agricultural diets.

Framework

Dual Passage. Both passages discuss the caries-agriculture link. Passage A presents the prevailing view (more agriculture = more caries) plus exceptions; Passage B applies that view to a specific archaeological site (Ban Chiang, Thailand) and finds an unexpected result.

Main Point

The prevailing view is that increased agricultural (carbohydrate-rich) diets cause more caries — but Passage B's Ban Chiang study found caries decreasing as agriculture increased, likely because the diet remained varied and shifted toward less cariogenic carbohydrates.

Passage A: The prevailing view, with exceptions

Caries strongly linked to sticky carbohydrates of agricultural diets. Leigh's North American study: meat-eating Sioux had almost no caries; maize-dependent Zuni had 75% caries — and But there are exceptions: nonagricultural populations eating processed acorn flour or wild plants high in cariogenic potential (Hopi pinyon nuts, wild tubers).

Passage B: Ban Chiang's anomaly

Ban Chiang, Thailand, transitioned from hunter-gatherer-cultivator to increasing agriculture over 2,000 years. Research generally says agricultural intensification declines health, including dental health. Caries is uncommon in pre-agricultural populations; tooth-wear (which removes fissures and reduces caries) is also a factor. Ban Chiang's diet included rice and yams from the start. Yet caries was slightly greater in the Early Group than the Late Group — opposite the expected pattern. Tooth-wear didn't explain it. Likely explanations: the late-period diet remained varied (no single food dominated), and there may have been a shift from yams (sweeter, more cariogenic) to rice (less cariogenic).

21.

The evidence from Ban Chiang discussed in passage B relates to the generalization reported in the last sentence of the second paragraph of passage A in which one of the following ways?

The evidence confirms the generalization.
Opposite: confirms
The evidence of Ban Chiang does not conform to the generalization, since as they went from Early to Late, they became increasingly dependent on agriculture but their rate of caries formation decreased slightly.
4% picked this
The evidence tends to support
Opposite: supports
The evidence of Ban Chiang does not conform to the generalization, since as they went from Early to Late, they became increasingly dependent on agriculture but their rate of caries formation decreased slightly.
19% picked this
The evidence is irrelevant to
Opposite: irrelevant
The evidence of Ban Chiang is relevant, since it includes information about dependence on agriculture and rates of caries formation, which is what the generalization was all about.
1% picked this
Correct
The evidence does not conform
Why this is right
Haha, okay this ended up being exactly like our prediction. That was an accident. But yes, we can sign off on this. The generalization is that "as dependence on agriculture goes up, rates of caries formation do too". And when it came to Ban Chiang, as dependence on agriculture went up, rates of caries formation actually fell slightly.
Skill tested: Application · how this choice captures the passage's function is the move to repeat next time.
70% picked this
The evidence disproves the generalization.
Too Strong: generalization
Generalizations aren't the same as universals. A universal is a specific type of general claim that allows for no exceptions. But a generalization is just saying that something is "generally" true. It's generally colder on Christmas than it is on Easter, in the Northern Hemisphere. But that doesn't have to be true all the time. If there's one year where Christmas is warmer than Easter, that doesn't disprove that Christmas is generally colder than Easter. Another way to know this answer must be wrong is that if it were right, then (D) would also be right. If the evidence disproved a generalization, then it clearly failed to conform to the generalization. We can never pick an answer that would also imply another answer. Ban Chiang's evidence does not fit the general connection between dependence on agriculture and higher rates of caries, but it doesn't disprove that generalization. Similarly, the existence of an NBA player that's only 5'10" doesn't disprove the generalization that "in general, NBA players are taller than 6 feet".
6% picked this

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