In view of the inherent properties of the main verbs in the above sentences, Berent (1983) explained deaf college students' abilities to interpret the logical subjects of infinitives in English on the basis of the predictability of the choice for logical subject. It just so happens that, with the vast majority of English verbs that can be followed by an infinitive clause, it is the noun phrase that is closest to the infinitive that is interpreted as the logical subject of the infinitive. In other words, most verbs that can be followed by an infinitive behave like the verb tell, as in the sentence below.
John told Mary to close the door.
In all of the sentences in the first cluster above, the main verbs are active and the logical subject is either the closer of two noun phrases or else it is the only noun phrase that precedes the infinitive. In the latter case, as the only noun phrase, it is by definition the closest to the infinitive, even if it is not the object of the main verb, as in:
Bill chose to stay at home.
In this sense, the choice of a logical subject in all of the sentences in the first cluster is predictable as the closest noun phrase to the infinitive. Therefore, the deaf students in the study were quite successful in interpreting the logical subjects of the infinitives in those sentences. Those sentences reflect the default "closeness principle," so students would be expected to interpret them correctly.
The second cluster of sentences, repeated below, contains structures in which the interpretation of logical subjects is arguably unpredictable with respect to the closeness principle.
Mike was reminded by George to study the lesson. (78%)
Bill promised George to wash the dishes. (65%)
Alice explained what to do. (59%)
Jim was told whom to visit. (57%)
John said to come at 7:30. (49%)
Tom asked Bill what to buy. (25%)
Larry was asked where to sit. (20%)
As discussed in the Grammatical Summary section, when a main verb is passive, the choice of logical subject is the reverse of what it is in a corresponding active sentence. This is seen by comparing one of the sentences from the first cluster with the first sentence of the second cluster:
Tom reminded George to do the homework.
Mike was reminded by George to study the lesson.
Accordingly, students' performance was worse on the passive sentence than on the active one. In the passive sentence, the logical subject is unpredictable, in terms of the closeness principle, in that it is the further, rather than the closer, noun phrase to the infinitive. However, with this particular pair of sentences, performance differed only by 10%. There are probably two reasons for this.
First, the explicit by-phrase in the passive sentence facilitates students' comprehension relative to passive sentences that do not contain a by-phrase. Note that none of the other passive sentences in the second cluster contains a by-phrase. Secondly, performance on the active sentence was probably lower than expected for "pragmatic" reasons. Even though 88% of the deaf students provided the target response to "Who did the homework?", some may have reasonably surmised that both Tom and George had the same homework assignment and therefore chose Tom as one acceptable answer to the question. None of the other sentences on the test has this pragmatic flaw.
With respect to the other sentences in the second cluster, two are unpredictable in terms of the closeness principle on the basis of the inherent properties that stipulate that the logical subject of the infinitive is the subject of the main verb. One sentence contains the exceptional verb promise and the other contains ask in its meaning of "request information" when it is followed by an infinitive clause that begins with a WH-word:
Bill promised George to wash the dishes.
Tom asked Bill what to buy.
Three of the sentences have logical subjects that are not contained within the sentence but are inferred from context.
Alice explained what to do.
John said to come at 7:30.
Larry was asked where to sit.
The interpretation of the logical subject is unpredictable in all of these sentences because the closest noun phrase--in these cases, the subject of the main verb--cannot serve as the logical subject of the infinitive.
Finally, the status of one of the sentences in the second cluster is interesting. On the following sentence, the deaf students were only 57% correct even though the sentence seems to conform to the closeness principle. Jim appears to be the only noun phrase preceding the infinitive and therefore the closest noun phrase.
Jim was told whom to visit.
However, the infinitive clause in this sentence begins with the WH-word whom, which refers to a person (in contrast to what and where in some of the other sentences). In addition to referring to a person, whom is in fact a noun phrase (both nouns and pronouns serve as noun phrases). Therefore, whom is the closest noun phrase to the infinitive, and so the interpretation of the logical subject indeed violates the closeness principle in this sentence. On the test that the students were given, the two choices for this sentence were Jim and another person. Thus, if a student perceived the sentence incorrectly as something like "Jim was told who visited," it is easy to see how another person would be a reasonable choice for logical subject.
Performance by Proficiency Level
The results discussed above were based on the overall performance of the 51 deaf college students in the Berent (1983) study. The deaf students actually represented three English proficiency levels: Low, Mid, and High. The students' performance by group illustrates how the distinction between predictable and unpredictable sentences helps to explain deaf students' knowledge about the logical subjects of infinitives.
On the predictable sentences, the three groups performed as follows, in terms of percentages correct:
These percentages demonstrate that the three groups of students performed almost perfectly and equally well on the predictable sentences. On the other hand, the performance pattern on the unpredictable sentences demonstrates that deaf college students' knowledge of the logical subjects of infinitives is much lower on these sentences but that it improves as overall English proficiency level increases.