Un contexto cada vez más polarizado

As was already discussed in section 3.1.2, the parallelism constraint was originally defined as a condition of parallelism of grammatical roles, subject goes to subject and object goes to object. A subject of an utterance is configurationally defined and refers to a syntactic position [Spec, IP] and an object in an utterance, such as the ones tested in this experiment, is a DP complement of a verb. A DP in the subject position of an active sentence is most likely to carry the thematic role of an agent and a DP in an object position is most likely to be the patient of the action expressed by the verb in question. Like any other DP in the syntactic structure, both subject and object DPs trigger the creation of individual file cards in discourse representation. The file card instantiated by the subject DP is marked as agent and an object DP instantiates an individual file card specified as carrying a patient thematic role.

The parallelism constraint can now be reformulated as the parallelism of thematic roles applying at the syntax-discourse interface. The information about the thematic role of a particular DP is mapped onto a file card created in discourse as agent or patient. In the case of the experimental sentences such as (21), the pronoun file card is marked as

agent and referentially deficient, i.e. it lacks a heading. Therefore, it will

establish a discourse dependency through a cut & paste operation with a file card that matches the thematic information of being agent. The same applies to sentences such as (22); the pronoun file card is marked as

patient; it will be connected with a file card marked as patient too in order

In the experimental sentences, in both conjuncts, the first DP encountered is the subject and agent and the second DP is the object and

patient. The thematic roles thus coincide with syntactic position. If the

second conjunct is transformed into a passive sentence such as in (23), the pronoun he is in the subject position. However, it is not agent but

patient. The second argument Susan found in the by-phrase is the agent in

the passive construction. The thematic role of the subject DP of the first clause does not match the thematic role of the subject pronoun of the second conjunct. In (23) the subject pronoun does not refer to the subject but to the object of the preceding clause and parallelism of thematic roles is obeyed. In (24) the first conjunct is a passive sentence and the agent is the second argument; Bill in the by-phrase. The subject pronoun he of the second conjunct carrying the thematic role of an agent refers to the second argument and not the subject DP John of the first conjunct.

(23) First John poked Bill and then he was poked by Susan. (he=Bill)

agent patient patient agent

(24) First John was poked by Bill and then he poked Susan. (he=Bill)

patient agent agent patient

Solan (1983) tested healthy adults and children in order to find out whether they rely on the parallelism of grammatical or thematic roles. He tested sentences similar to the ones in (23) and (24) creating conditions where the thematic roles were the same in the first and the second conjunct but the grammatical roles were not; the first conjunct was a passive sentence and the second one an active sentence and vice versa. In the base line conditions both first and second conjuncts were either active or passive sentences. He found that adults vacillate between the use of thematic and grammatical roles. In (23) they allow both subject and object DPs to serve as antecedents for the subject pronoun in the second conjunct. In (24) they allow both the subject DP and the second argument DP in the by-phrase to serve as antecedents for the subject pronoun in the second conjunct. Children, on the other hand, rely heavily on the information about thematic roles. For them the subject

pronoun in the second conjunct in (23), which is also the patient, refers to the patient DP of the first conjunct regardless of the fact that the two are not parallel in terms of grammatical roles. The same applies to the example in (24): the subject pronoun, which is the agent, refers to the grammatically non-parallel agent of the first conjunct.

It seems that what is parallel in the interpretation of pronouns in sentences such as the ones I tested are not only the grammatical roles but also the thematic roles. I will describe now how the parallelism constraint should work at the level of discourse representation and be applied to the experimental sentences repeated in (25) and (26).

(25) Eerst heeft het meisje de vrouw geknepen en daarna heeft zij de man geknepen.

First the girl pinched the woman en then she pinched the man. (26) Eerst heeft het meisje de vrouw geknepen en daarna heeft de man

haar geknepen.

First the girl pinched the woman en then the man pinched her. The agent of the second conjunct in (25) is a DP zij, which in discourse triggers the creation of an individual file card marked as agent. Because this file card lacks a heading, it will establish a discourse dependency through a cut & paste operation with a matching file card that is also marked as agent. In the case of (25) it is the individual file card instantiated by the agent DP het meisje of the first conjunct. The information from this file card will be cut and pasted onto the pronoun file card in order to provide it with referential content (heading). Similarly, the file card associated with the patient DP haar in the second conjunct in (26) will establish a dependency with the file card that is marked as patient in the first conjunct. This is the file card associated with the patient DP de vrouw in the first conjunct.

So, in order to correctly interpret such coordinated sentences three different kinds of information need to be consulted. First, the syntactic structure must be computed and become available for the patients in order to assign the grammatical roles to the DPs, in the first conjunct first and then in the second conjunct. Secondly, the lexical-semantic knowledge of thematic roles has to be supplied by the verbs in relation to the syntactic structure in both conjuncts. Thirdly, the discourse knowledge of parallelism must be applied, according to which the relationship between entities must first be established in the first conjunct and then applied in parallel in the second conjunct. Finally, all

this information must be retained in short-term memory for both conjuncts in order to apply parallelism.

As I put forth in the previous chapter, the brain damage in Broca’s aphasic patients results in protracted syntactic structure building which, in turn, allows other linguistic levels, such as discourse, to provide the source of reference although it should not. Following the same reasoning, I assume that the syntactic structure building in the sentences tested in the present experiment is also protracted. In addition to the timely availability of syntactic information in these sentences, the semantic information must also become available on time and the discourse constraint on parallelism, dependent on both syntactic and semantic information, also needs to be computed on time. The timely availability of both structural and semantic information is disturbed in agrammatic patients; this information is also not retained in memory long enough for it to be used while computing parallelism. They therefore fail to apply parallelism but their errors are not random. There is another rule, an escape hatch provided by discourse which takes over as a kind of a default rule when their system runs into trouble with these types of sentences. This rule is the topic preference also at play in healthy adults who use it as an escape route when there is ambiguity in the form of a number of different antecedent candidates for the pronoun. In the following section I will discuss topic preference.