Let us now examine the problem mentioned at the beginning of this chapter: the difficulty that some students have comprehending textbooks containing sentences with relative clauses. Here is a paragraph from the Encyclopedia Americana.
Infectious diseases are the only ones that can be transmitted. They may be spread by infected animals, infected people, or contaminated substances, such as food and water. Infectious diseases that can be transmitted to humans from infected animals are known as zoonoses. Zoonoses may be transmitted by carriers, such as insects; by the bite of an infected animal; by direct contact with an infected animals [sic] or its excretions; or by eating animal products.
College freshman were asked to read this paragraph and then answer the following questions.
Zoonoses are:College students with weak reading skills often pick alternative b. When asked why they picked b, some reply that zoonoses sounds like zoo and animals are kept in zoos, so they figured zoonoses are animals. This explanation reflects the thinking style of nonanalytical readers. They base their conclusions on superficial associations among bits of information rather than on careful step-by-step interpretations of chunks of information and gradual reconstruction of total meaning.
a. insects that carry diseases.
b. infected animals that transmit infectious diseases to humans.
c. infectious diseases that man gets from animals.
d. carriers that transmit infectious diseases.
Other students who chose b explained that they got this answer from the last six words of the third sentence: infected animals are known as zoonoses. This, too, reflects the thinking style of weak readers. They read a little bit here, a little bit there, and then jump to a conclusion.
The correct answer is based on the third sentence, which reads:
Infectious diseases that can be transmitted to humans from infected animals are known as zoonoses.
This sentence contains the following relative clause:
that can be transmitted to humans from infected animals
Good readers work step-by-step through the sentence in obtaining its correct meaning. They begin with the subject: infectious diseases. Then they go on to the relative clause, an essential relative clause that indicates the type of infectious diseases being considered; those that animals can transmit to humans. Finally, they come to the predicate: are known as zoonoses. Therefore, in answering the question they pick alternative c.
Research studies have found that students with weak analytical skills can understand only simple sentences, just as they can solve only one-step math problems. They have difficulty understanding complicated sentences, just as they have difficulty solving multi-step math problems. In other words, they can handle just small chucks of information because they have not developed skill in working step-by-step through complicated information. They can understand sentences such as this:
Some infectious diseases are known as zoonoses.
But they cannot understand Sentence 3 in the paragraph.
Other research studies (reviewed in Why Johnny can't Write: How to Improve Writing Skills) have found that having students construct complex sentences from simple ones improves their scores on standardized reading tests. these studies have not explored whether having students add relative clauses to sentences improves their ability to comprehend specifically sentences with relative clauses. They have only found that constructing various types of complicated sentences from simpler ones (using the types of exercises shown in this book) improves overall reading comprehension ability, with the weakest readers making the greatest gains. As the P-C Approach* is used more widely in our schools,** we can expect the average reading comprehension ability of the nation to improve. And as this improvement becomes evident, researchers may conduct additional studies to determine exactly how and why having students manipulate, construct, and write sentences improves their reading skills.
Teaching and Learning Grammar: The Prototype-Construction Approach
** I'm not holding my breath