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- Joined: Feb 02, 2011
- Fri Jan 21, 2011 12:00 am
#36310
Complete Passage Discussion
Passage A
The passage argues that since carbohydrate consumption causes dental caries (decay), prehistoric
human teeth can provide clues about when a population made the transition from a hunter-gatherer
diet to a carbohydrate-rich agricultural one.
Paragraph 1 Overview
This paragraph introduces several factors that can affect the formation of dental caries (decay)—
tooth structure, bacteria in the mouth, and diet. Of these factors, diet is especially important to the
author’s argument. Carbohydrate-rich foods are common staples in agricultural diets. Because the
formation of dental caries is strongly linked to the consumption of carbohydrates, the author believes
that prehistoric human teeth can provide evidence about when a population made the transition from
a hunter-gatherer diet to an agricultural one.
Paragraph 2 Overview
The second paragraph brings in additional evidence to support the correlation between a population’s
dependence on agriculture and its rate of caries formation. In particular, the author describes a
study by Leigh comparing indigenous populations in North America that primarily consumed meat
(low rate of caries formation) to those heavily dependent on cultivated maize (high rate of caries
formation). Other researchers have also confirmed this correlation.
Paragraph 3 Overview
In the final paragraph, the author concedes that some nonagricultural populations, such as those
in western North America as well as the Hopi, may also exhibit high caries rates due to their
consumption of foods with high cariogenic potential (as an aside, do not be put off by the word
“cariogenic”; it simply means “decay causing”). Although this information does not disprove the
correlation cited in the second paragraph, it shows that the correlation is not perfect.
Summary
Overall, the author believes that a population’s dependence on agriculture tends to increase its rate
of caries formation, due to our consumption of cariogenic carbohydrate-rich foods. This hypothesis
is not without limitations, as some nonagricultural populations can also exhibit high caries rates.
Nevertheless, the author is confident that prehistoric human teeth can be used as evidence to
determine when a population transitioned from a hunter-gatherer diet to an agricultural one.
As a whole, the passage is not overly complex, especially if you recognized the causal reasoning
framework inherent in the author’s logic. Although we study causal reasoning primarily in the
context of Logical Reasoning questions, causality in Reading Comprehension is often used to
explain why certain events occurred, and is not typically viewed as flawed reasoning.
Passage B
The second passage focuses on the archeological findings at the Ban Chiang site in Thailand.
Although the site’s early inhabitants appear to have had a hunter-gatherer-cultivator economy, the
population gradually became dependent on agriculture. Surprisingly, the rate of caries formation
decreased over time, suggesting that increased reliance on agriculture does not necessarily lead to an
increase in caries frequency.
Paragraph 1 Overview
The first paragraph opens with a description of the passage’s central focus: the inhabitants of the
prehistoric Ban Chiang site in Thailand, who transitioned from a hunter-gatherer-cultivator diet to an
agricultural one.
Paragraph 2 Overview
For the most part, the research findings described in the second paragraph agree with those in
Passage A—agricultural intensification can lead to increased caries frequency. Note, however, that
consumption of carbohydrate-rich foods is not the only way to explain this relationship; alterations in
tooth wear can also play a role. Since agricultural diets reduce our intake of fiber, they can diminish
tooth wear and promote caries formation. Interestingly, too much tooth wear may also result in
caries.
Paragraph 3 Overview
Here the author describes the diet of Ban Chiang’s inhabitants in greater detail. Since they consumed
a varied diet that initially included some carbohydrate-rich foods, the author alleges that increased
reliance on such foods should theoretically result in increased caries frequency. Note the speculative
language in the last sentence, suggesting that agricultural intensification did not actually result in
increased caries frequency, as shown in the next paragraph.
Paragraph 4 Overview
The fourth paragraph compares caries frequency in the Early and Late Ban Chiang Groups.
Surprisingly, the rate of caries formation among the Ban Chiang’s inhabitants did not increase as
they transitioned into a predominantly agricultural diet; on the contrary—caries frequency was
slightly greater in the Early Group than in the Late Group. Since no alterations in tooth wear were
observed, the author proposes two ways to explain the unexpected results:
Overall, the author does not dispute the prevailing view that agricultural intensification can result
in declining dental health. However, the counterexample of the Ban Chiang population presents a scenario in which the cause occurs without the effect, suggesting that agricultural diets do not always
result in increased caries frequency. The passage is slightly more difficult than Passage A, but you
can still rely on your understanding of causal reasoning to break it down.
Passage Similarities:
There is considerable agreement on the relationship between carbohydrate consumption and
caries formation between the two authors. Both believe that the consumption of carbohydrate-rich
foods can increase the incidence of dental caries, a view both passages support by observing that
dental caries is uncommon in nonagricultural populations. The two authors also agree that some
carbohydrate-rich foods have a higher cariogenic potential than others. Both passages examine the
prevailing view that agricultural intensification tends to increase the incidence of caries formation in
a population, and both express reservations suggesting that the correlation is not perfect.
Passage Differences:
While the topics of the passages are similar, the first author exhibits a slightly higher degree of
confidence in the prevailing view that increased dependence on agriculture leads to higher rates
of caries formation. Unlike the second passage, Passage A cites specific studies confirming this
correlation, and only briefly describes any exceptions in the last paragraph.
By contrast, the main focus of Passage B is the counterexample of the Ban Chiang inhabitants,
suggesting that a population’s dependence on agriculture may actually decrease its rates of caries
formation. Interestingly, Passage A presents a counterexample in which the effect occurs without the
cause, whereas Passage B describes a scenario in which the cause occurs without the effect. Passage
B also offers a more elaborate view of the causal relationship between agricultural diets and caries
formation, suggesting that carbohydrate consumption and alterations in tooth wear can each play a
role in caries formation.
Passage A
The passage argues that since carbohydrate consumption causes dental caries (decay), prehistoric
human teeth can provide clues about when a population made the transition from a hunter-gatherer
diet to a carbohydrate-rich agricultural one.
Paragraph 1 Overview
This paragraph introduces several factors that can affect the formation of dental caries (decay)—
tooth structure, bacteria in the mouth, and diet. Of these factors, diet is especially important to the
author’s argument. Carbohydrate-rich foods are common staples in agricultural diets. Because the
formation of dental caries is strongly linked to the consumption of carbohydrates, the author believes
that prehistoric human teeth can provide evidence about when a population made the transition from
a hunter-gatherer diet to an agricultural one.
Paragraph 2 Overview
The second paragraph brings in additional evidence to support the correlation between a population’s
dependence on agriculture and its rate of caries formation. In particular, the author describes a
study by Leigh comparing indigenous populations in North America that primarily consumed meat
(low rate of caries formation) to those heavily dependent on cultivated maize (high rate of caries
formation). Other researchers have also confirmed this correlation.
Paragraph 3 Overview
In the final paragraph, the author concedes that some nonagricultural populations, such as those
in western North America as well as the Hopi, may also exhibit high caries rates due to their
consumption of foods with high cariogenic potential (as an aside, do not be put off by the word
“cariogenic”; it simply means “decay causing”). Although this information does not disprove the
correlation cited in the second paragraph, it shows that the correlation is not perfect.
Summary
Overall, the author believes that a population’s dependence on agriculture tends to increase its rate
of caries formation, due to our consumption of cariogenic carbohydrate-rich foods. This hypothesis
is not without limitations, as some nonagricultural populations can also exhibit high caries rates.
Nevertheless, the author is confident that prehistoric human teeth can be used as evidence to
determine when a population transitioned from a hunter-gatherer diet to an agricultural one.
As a whole, the passage is not overly complex, especially if you recognized the causal reasoning
framework inherent in the author’s logic. Although we study causal reasoning primarily in the
context of Logical Reasoning questions, causality in Reading Comprehension is often used to
explain why certain events occurred, and is not typically viewed as flawed reasoning.
Passage B
The second passage focuses on the archeological findings at the Ban Chiang site in Thailand.
Although the site’s early inhabitants appear to have had a hunter-gatherer-cultivator economy, the
population gradually became dependent on agriculture. Surprisingly, the rate of caries formation
decreased over time, suggesting that increased reliance on agriculture does not necessarily lead to an
increase in caries frequency.
Paragraph 1 Overview
The first paragraph opens with a description of the passage’s central focus: the inhabitants of the
prehistoric Ban Chiang site in Thailand, who transitioned from a hunter-gatherer-cultivator diet to an
agricultural one.
Paragraph 2 Overview
For the most part, the research findings described in the second paragraph agree with those in
Passage A—agricultural intensification can lead to increased caries frequency. Note, however, that
consumption of carbohydrate-rich foods is not the only way to explain this relationship; alterations in
tooth wear can also play a role. Since agricultural diets reduce our intake of fiber, they can diminish
tooth wear and promote caries formation. Interestingly, too much tooth wear may also result in
caries.
Paragraph 3 Overview
Here the author describes the diet of Ban Chiang’s inhabitants in greater detail. Since they consumed
a varied diet that initially included some carbohydrate-rich foods, the author alleges that increased
reliance on such foods should theoretically result in increased caries frequency. Note the speculative
language in the last sentence, suggesting that agricultural intensification did not actually result in
increased caries frequency, as shown in the next paragraph.
Paragraph 4 Overview
The fourth paragraph compares caries frequency in the Early and Late Ban Chiang Groups.
Surprisingly, the rate of caries formation among the Ban Chiang’s inhabitants did not increase as
they transitioned into a predominantly agricultural diet; on the contrary—caries frequency was
slightly greater in the Early Group than in the Late Group. Since no alterations in tooth wear were
observed, the author proposes two ways to explain the unexpected results:
- 1. The diet in the Late period remained varied enough that no single food dominated;
2. There may have been a shift from sweeter carbohydrates (yams) toward rice, a less cariogenic
carbohydrate.
Overall, the author does not dispute the prevailing view that agricultural intensification can result
in declining dental health. However, the counterexample of the Ban Chiang population presents a scenario in which the cause occurs without the effect, suggesting that agricultural diets do not always
result in increased caries frequency. The passage is slightly more difficult than Passage A, but you
can still rely on your understanding of causal reasoning to break it down.
Passage Similarities:
There is considerable agreement on the relationship between carbohydrate consumption and
caries formation between the two authors. Both believe that the consumption of carbohydrate-rich
foods can increase the incidence of dental caries, a view both passages support by observing that
dental caries is uncommon in nonagricultural populations. The two authors also agree that some
carbohydrate-rich foods have a higher cariogenic potential than others. Both passages examine the
prevailing view that agricultural intensification tends to increase the incidence of caries formation in
a population, and both express reservations suggesting that the correlation is not perfect.
Passage Differences:
While the topics of the passages are similar, the first author exhibits a slightly higher degree of
confidence in the prevailing view that increased dependence on agriculture leads to higher rates
of caries formation. Unlike the second passage, Passage A cites specific studies confirming this
correlation, and only briefly describes any exceptions in the last paragraph.
By contrast, the main focus of Passage B is the counterexample of the Ban Chiang inhabitants,
suggesting that a population’s dependence on agriculture may actually decrease its rates of caries
formation. Interestingly, Passage A presents a counterexample in which the effect occurs without the
cause, whereas Passage B describes a scenario in which the cause occurs without the effect. Passage
B also offers a more elaborate view of the causal relationship between agricultural diets and caries
formation, suggesting that carbohydrate consumption and alterations in tooth wear can each play a
role in caries formation.