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Artigo publicado em Recherches Linguistiques de Vincennes nº 26, p.151-172, França, 1997.1

The processing of object anaphorain Brazilian Portuguese*

Marcus MaiaFederal University of Rio de Janeiro - Brasil

[email protected]

1. Introduction

The comprehension of anaphoric relations is an essential feature of

human sentence processing. The basic processing issues concerning

coreference assignment revolve around the questions of if, when and

how the correct coreferential relationships are established among

elements in a sentence. Typically the focus of the research has centered

on the ability of referentially-dependent elements such as overt

pronouns and empty categories to facilitate the comprehension of a

previously mentioned noun phrase (NP), or antecedent. A number of

recent studies in Psycholinguistics have shown the processing

relevance of empty categories and pronouns in English. That is to say,

these elements have been shown to be psychologically real in the sense

that they trigger a reactivation1 of their antecedents.

Chang (1980) conducted experiments that demonstrated that

recognition responses for a person's name were significantly faster

* This article is based on research I conducted for my doctoral dissertation (Maia, 1994) at thePsycholinguistics lab in the department of linguistics of the University of Southern California -USC. I am indebted to Maryellen MacDonald, Joseph Aoun, Mark Seidenberg and MariaLuiza Zubizarreta for helpful comments and suggestions. The material in section 3 of the articlewas presented during the 6th Annual CUNY Sentence Processing Conference at the Universityof Massachusetts (Amherst) in1993. I am grateful to that audience for many insightfulquestions. I would also like to thank Zlatka Guentcheva for having encouraged me to submit afirst draft of the paper to RLV and the two RLV anonymous reviewers who have madeimportant suggestions concerning the form and the content of the article. Of course, I am thesole responsible for any remaining mistakes.

1 According to Fodor (1989) "reactivation" may be a matter of excitation of the relevant entryin the mental lexicon or of the relevant concept in the semantic representation beingconstructed for the sentence.


when a final clause contained a pronoun referring to the person than

when it did not. Cowart and Cairns (1987) showed that the initial

assignment of an antecedent to a pronoun obeys structural constraints,

but not constraints on semantic or pragmatic well-formedness. Their

experiments suggests that a pronoun triggers all and only those prior

referents that are structurally appropriate as the antecedent. They

argue that there is a device that computes coreference, and that this

device has access to structural information, but not to what is often

considered to be "higher level" information, such as semantics and

pragmatics.

Several studies have also been conducted in order to assess whether

similar effects could be established for antecedents of different types of

empty categories. For example, Bever & McElree (1988) have found

evidence that gaps access their antecedents during comprehension in

the same way as overt pronouns and that gaps produced through

movement access their antecedents more strongly than the null

pronominal PRO. MacDonald (1989) conducted a study in which NP-

traces are shown to unequivocally prime their antecedents in passive

constructions in English. Gap and non-gap conditions differed by only

one word, ruling out the possibility that differences in reaction times

could be attributed to differences in the processing loads.

Besides answering the question concerning the perceptual reality of

coreference assignment, the research on the processing of gaps has also

been particularly informative with respect to the questions of decision

principles and constraints on information use in the comprehension of


sentences. As a matter of fact much of the recent research on sentence

understanding has focused on identifying the types of information

available to the sentence processor or parser during comprehension.

Two views about the type of information accessed during

comprehension have dominated the literature. According to one

position, the parser rapidly builds a syntactic skeleton by making use of

phrase structure rules and simple decision principles such as the

minimal attachment principle, by means of which "incoming material

is attached into the phrase marker being constructed using the fewest

nodes consistent with the well-formedness rules of the language"

(Frazier, 1979, p.76). As in such a system syntactic category

information is the primary input and other sources of information are

basically ignored, many mistakes usually arise in the form of the so-

called "garden-path" phenomenon. On this view, combinatory lexical

information such as subcategorization information can only be used in

reanalysis after the parser's original analysis fails (Ferreira & Clifton,

1986). According to Frazier et al. (1983), for example, subcategorization

information is not available to the parser in the initial stages of

syntactic processing. In keeping with the idea of a parsing system in

which syntactic category information constitutes the primary source of

information, Clifton & Frazier (1989) also proposed the "active filler

hypothesis", according to which a gap would be postulated on the

basis of antecedent information well before the verb subcategorization

could be accessed. Clifton & Frazier propose that as long as it has an

unassigned filler in a nonargument position, the parser prefers to posit

a gap for the filler rather than take into consideration the lexical

properties of the head of the phrase. If subcategorization information


about the verb is inconsistent with the postulation of the gap, the

hypothesized gap is deleted.

Another view proposes that the comprehension system rapidly and

optimally integrates lexical, syntactic and contextual information in

some form of mental representation. In such a system, the immediate

access to argument and control structure information would allow the

parser to project structure and avoid indeterminacy (Crain &

Steedman, 1985). Thus, the question whether lexical information can be

accessed in the initial stages of the parsing process is far from settled,

since several types of on-line processing evidence have made a strong

case that combinatory lexical information is immediately used in

parsing (e.g. Stowe, 1989; Tannenhaus, Stowe & Carlson, 1985;

Tannenhaus & Carlson, 1989.) In sum, several studies of filler-gap

sentences provide evidence that the language processor has rapid

access to both argument structure and control information. Such results

complement an increasing body of research demonstrating that lexical

information may play an immediate role in guiding parsing decisions.

In this article, we present evidence in favor of the processing relevance

of gaps which refer to topics (A'-bound gaps) in Brazilian Portuguese

(BP). As it will be argued in section 3, our data also seem to confirm

that subcategorization information is indeed accessed by the parser at

early stages of comprehension.

The psycholinguistic experiment which is reported in section 3 has also

an important bearing on the issue of topic availability or identification


which has been investigated in the framework of functional grammar.

Within this area of linguistic study clauses have traditionally been

thought of as made up by two distinct components: the comment or

"rheme" which carries the new information and the topic or "theme"

which is usually identified with the old information. Additionally,

authors have also investigated the degree of difficulty that

speakers/hearers may experience in identifying a topic, that is, in filing

it appropriately in their internal register, so that the new information

transmitted about the topic would in turn be addressed adequately. In

Givón (1983) several studies are reported which have attempted to

establish a scale in the coding of topic accessibility. By analyzing texts

in different languages, authors have endeavored to assess the

grammatical devices used by the speaker to code various topics in the

discourse. According to Givón, a scale of crosslinguistic coding devices

may be used to indicate topic continuity in discourse. These studies

have been couched in terms of the speaker-hearer neutral notion of

discourse continuity, rather than in terms of the more psychologically

oriented notion of accessibility. The assumptions underlying these

studies, however, have a psychological import: what is continuing is

more predictable; what is predictable is easier to process. However, as

these measurements were performed on texts rather than on speakers

or hearers, they could not tap into the issue of topic identifiability in a

direct way, since they could not reveal the ease or difficulty hearers

experience in processing and filing topics in discourse. Therefore, these

studies lacked empirical psychological justification. In this respect,

Givón (1983) states :


"Hopefully, once stable, strong and cross-linguistically viablecorrelations are established (...), one may proceed to the obvious nextstep, that of correlating the grammatical and discourse-distributiondata with psycholinguistic experimentation and measurement." (Givón,1983, p. 13).

In this article, we provide psycholinguistic evidence which takes the

research on topic accessibility to the "obvious next step" proposed by

Givón. One of the findings of the experiment reported in the next

section is that the zero-anaphora in object position exhibit a stronger

psychological reactivation of topics than the overt lexical pronoun in

the same position. These results are entirely in line with the cross-

linguistic text measurements performed by Givón et alii (1983), and

provide partial psychological justification for Givón's scale of topic

accessibility.

This article is organized as follows. In section 2, a general overview on

the relevant aspects of the grammar of BP is provided. In section 3, we

present experiment 1 which compares the reactivation properties of

gaps and overt pronouns in a probe recognition task, and discuss the

relevance of the BP facts for the architecture of the human parser. In

section 4, we discuss our experimental results in the light of the

Overt Pronoun Constraint proposed by Montalbetti (1984) and

present experiment 2, which compares the strict/sloppy interpretation

of overt and nonovert objects in a speeded grammaticality judgment

task. Finally, in section 5, we summarize the general conclusions of the

paper.

2. BP : an overview


Brazilian Portuguese is a pro-drop language with an SVO basic word

order. It has a rich verbal inflection system which indicates person,

number, tense and mood by means of suffixes. As other Romance

languages such as Italian, Spanish, and Catalan, it allows missing

subjects. Unlike Italian and like Chinese or Japanese ( cf. Huang, 1984;

Hasegawa, 1985) , it allows missing objects, even though there is no

object morphological agreement. Although BP also has a paradigm of

object pronouns or clitics which is similar to the system generally

found in the Romance languages, it is a well known fact that clitics

are disappearing in oral BP and even in informal written BP. Tarallo

(1984) analyzed 45 hours of recorded data in which no third person

clitics were observed whatsoever and the only third person pronouns

in object position were the full lexical pronouns. Similarly, Duarte

(1989) has also shown in her sociolinguistic study on the use of the

accusative clitic, the lexical pronoun and the null object in colloquial

BP, that the null object occurs in 62.6% of the utterances in her 40 hour

corpus, whereas the clitic appears in only 4.9 % of the sentences, the

full nominative pronoun in 15.4 % and anaphoric NPs in 17.1% of

the cases. Therefore, although BP has a system of object clitics which

is still productive in formal registers, BP speakers generally prefer to

resort either to the gap or to the nominative lexical pronoun, as

exemplified in (2) and (3), avoiding clitic constructions such as (4):

(1) Você viu o João i ? "Did you see João ? "

(2) - Vi [e]i ontem no clube.saw [e]i yesterday in the club

"I saw (him) yesterday in the club."


(3) - Vi ele i ontem no clube.saw he i yesterday in the club

"I saw him yesterday in the club."

(4) - Vi-oi ontem no clube.saw him i yesterday in the club

"I saw him yesterday in the club."

This ability to drop objects, which approaches BP from so called "cool"

languages2 such as Chinese, is not shared to the same extent by any

other Romance language, including European Portuguese (EP). In EP

null objects are not so frequent and alternate only with the clitic.

Sentences such as (3) above, as Galves (1989) points out, would be

absolutely ungrammatical in EP, what suggests that the underlying

structure of (2) is different in the two dialects of Portuguese.

Another important feature of BP which is directly relevant for the

purposes of this paper concerns the distribution of topic constructions.

Topic structures are so frequent in BP that Pontes (1987) proposed that

BP must be classified as either a topic prominent type of language or at

least as a language in which both the notions of subject and topic are

equally prominent. Additionally, in her important study on topics in

BP, Pontes (1987) shows that topic structures in which the comment

clause does not contain an element which is anaphorically related to

2 Following Ross (1982), Huang (1984) suggests that languages may be classified as hot,medium or cool, on the basis of the degree of explicitness with which they express certainanaphoric elements. English would be a "hot" language because pronouns cannot in general beomitted from grammatical sentences. Spanish would be a "medium" type of languagebecause it allows the deletion of subject pronouns but not of object clitics. Chinese as well asBrazilian Portuguese would be examples of "cool" languages since pronouns are usuallyomissible from grammatical sentences.


the element to the left of S are very common in BP. This is what Chafe

(1976) calls "Chinese style" topic structure. Typical examples are (5)

and (6):

(5) Aquele fogo, ainda bem que o corpo de bombeiro chegou.“That fire-i, fortunately the fire brigade arrived.”

(6) Peixe, Dourado é o melhor para mim.“Fish, Red snapper is the best for me.”

As we will show in section 3, topic-comment constructions in BP are

not only frequent, but they also seem to be processed as readily as the

subject-predicate type. We also present experimental data which

seem to suggest that there may be structural and processing constraints

underlying the preference for the empty category in object position in

BP topic constructions. Our data seem to confirm findings by Teixeira

(1985), Pontes (1987) and Callou et al (93) which indicate that

resumptive pronouns in object position are not productive in BP. We

show that these elements do not exhibit the same reactivation

properties as topic-bound gaps and a parsing explanation is suggested:

in languages which have the option between overt and empty

elements, a default strategy is operative so that overt elements check

for their possible antecedents within the sentence as a first resort,

whereas gaps can establish coreference with elements outside S more

directly.

3. Experiment 1: priming effects of gaps and overt pronouns in

object position in BP


This experiment compared the processing of overt pronouns and

empty categories in object position in Brazilian Portuguese in structures

in which these anaphors are A-bound by a subject and in structures in

which they are A-bar-bound by an antecedent in topic position.

3.1. Method

In this section we describe the participants, the materials and design as

well as the testing procedures used in the experiment.

3.1.1. Subjects

Forty-eight (48) USC, UCLA and UC Berkeley brazilian

undergraduate and graduate students participated in this experiment.

All were native speakers of brazilian portuguese with normal or

corrected vision and normal hearing.

3.1.2. Materials and Design

The stimuli were 12 sets of 60 sentences (see appendix 1 for the

complete lists). Each subject was presented one of these experimental

sets embedded in an extra set of 60 filler sentences. Each experimental

set was made up of 6 experimental conditions and 6 control conditions

with five sentences per condition in a 3x2x2 type of design. There were

two levels of matrix (topic/subject), three levels of subordinate clauses(

gapless, overt pronoun, empty category), and two levels of probe

(antecedent, other). Table 1 provides an example of each of the

experimental conditions tested in the experiment. The control

conditions were the same as the experimental conditions except that a

probe other than the antecedent of the overt pronoun or gap was


presented. This other probe was the subject of the matrix clause in the

case of the topic sentences and the subject of the embedded clause in

the case of the subject sentences. Notice that although sentences were

very similar, differing only in terms of the tested variables, they were

distributed between subjects, so that each subject saw only one version

of each sentence type. The distribution of sentence types in 12 sets

allowed all sentences of a type to be compared. To provide a

counterbalance for the extra NP required in the topic sentences, all

subject sentences had an extra PP in the matrix clause in order to try to

rule out the possibility that differences in reaction times could be

caused by different processing loads rather than by the experimental

factors .

Table 1

(7) Subject-bound null object

A moradorai disse agora mesmo na entrevista à televisão que os

bombeiros já estão ajudando [e] i.

"The resident said right now in the interview to the television that the

firemen are already helping"

(8) Subject-bound overt pronoun

A moradorai disse agora mesmo na entrevista à televisão que os

bombeiros já estão ajudando elai.


firemen are already helping her"

(9) Gapless subject structure


A moradora disse agora mesmo na entrevista à televisão que os

bombeiros já estão chegando.


firemen are already arriving."

(10) Topic-bound null object

Os desabrigadosi, a moradora disse agora mesmo na entrevista que os

bombeiros já estão ajudando [e] i.

"The homeless, the resident said right now in the interview that the

firemen are already helping ."

(11) Topic-bound pronoun

Os desabrigadosi, a moradora disse agora mesmo na entrevista que os

bombeiros já estão ajudando eles i


firemen are already helping them."

(12) Gapless topic structure

Os desabrigados, a moradora disse agora mesmo na entrevista que os

bombeiros já estão chegando.


firemen are already arriving ."

3.1.3. Procedure

The study used a cross-modal priming technique. Subjects were

given a probe recognition task in which target sentences were orally

presented and reaction times to visual probes corresponding to the


antecedent of the overt pronoun and of the gap were measured in the

case of the experimental sentences. For the control sentences, we

measured reaction times to visual probes corresponding to the subject

of the matrix clause in the case of the topic sentences and to the subject

of the embedded clause in the case of the subject sentences.

Subjects indicated whether or not the probe word had occurred

anywhere in the sentence by pressing a yes or a no key in a button box.

This response removed the probe and presented a comprehension

question on the screen which should also be answered by pressing a

yes or a no key in the button box. Following three practice trials,

experimental, control and filler sentences were presented in a different

random order to each participant. Subjects were tested individually in

sessions of approximately 25 to 30 minutes and generally reported in

post-session interviews that the task was at least moderately easy.

3.2. Results

The logic of the experiment was as follows. A consistent finding of

recent studies on coreference processing is that reference-dependent

sentential elements seem to trigger reactivation of the antecedent NP's

to which they refer. This reactivation or "priming effect" of overt and

implicit anaphoric elements has been found both in studies which

checked for on-line probe recognition and in studies which use end-of-

sentence probes as it is the case in our experiment. By recording and

comparing reaction times to the experimental and control sentences

across the 6 conditions we expected to assess whether pronouns and

empty categories in object position in BP would facilitate the access to


their antecedents and whether this facilitation effect would vary with

relation to the subject/ topic nature of the antecedent. The extent to

which the reactivation of subjects and topics by the empty and by the

overt anaphors varied with relation to the gapless conditions is shown

in Figure 1. The gapless condition may be taken as a baseline in order

to ascertain whether or not the presence of structural constraints will

affect comprehension. The configuration in Figure 1 indicates that

there are no significant differences between the processing times for

the gapless topic and subject constructions. No matter how the human

sentence processor copes with topic structures, the final results for the

BP data show that comprehenders deal with topic-comment relations as

fast as they deal with subject-predicate relations. This finding provides

interesting processing evidence in favor of the claim that BP is a

language in which topic/comment relations are as prominent as

subject/predicate relations.

gapless pronoun [e]900

1000

1100

1200

1300

topicsubject

Graph 1: topics and subjects,antecedents

anaphor

Rea

ctio

n T

imes

(ms)

Figure 1: Topics and Subjects as antecedents


Our data show a stronger priming effect for the gap coindexed with

the topic (the A'-bound gap) than for the gap coindexed with the

subject (A-bound gap) and stronger priming effects for the overt

pronoun coindexed with the subject than for the overt pronoun

coindexed with the topic. In the topic sentences, reaction times to the

antecedent probe were 180 milliseconds faster in the gap condition than

the gapless condition, [F(1, 48) = 12.07, p < .05]. In the case of the

subject sentences, response times to the antecedent probe were 187

milliseconds faster in the pronoun condition than the gapless

condition, [F(1, 48) = 10.06, p < .05]. These are clearly significant

statistical results, showing an interaction between sentence type and

anaphor. In sum, Experiment 1 provides evidence that antecedents in

A-position have a preference for overt anaphoric elements, whereas

elements in A'-position prefer to be coindexed with empty categories.

3.3. Discussion

3.3.1. Subcategorization Information

An important issue in Sentence Processing has been whether the

language processor has rapid access to argument structure in parsing.

Another related issue concerns the positing of gaps based on

antecedent information. Clifton and Frazier (1989) claim that gaps are

posited as a first resort, that is, the parser makes use of antecedent

information in order to decide whether or not to hypothesize a gap in a

sentence. Our results suggest that the parser has immediate access to

subcategorization information and that a gap does not seem to be

posited on the basis of antecedent information. Notice that RT's to the

gapless cases are not significantly different. That is, subject/predicate


relations seem to be handled as readily as topic/comment relations.

However, if the parser were to posit a gap as a first resort it would be

legitimate to expect that gapless topic sentences should take longer to

process than gapless subject sentences since only in the topic case a gap

would be mistakenly posited. If these BP sentences were parsed

according to the Active filler hypothesis (Clifton & Frazier(1989)), the

processor should postulate an empty category right after it identified a

filler in nonargument position, in our case the topic. However, by

pursuing such a strategy, the processor would be garden-pathed

because the positing of a gap would be wrong in this case, since the

verb in the embedded clause is intransitive and projects no empty

category. Both the positing of the gap and the "surprise" reaction by

the processor should presumably take processing time. However this is

not the case in our data, since as we have showed above there is no

significant difference between the processing times for the topic and the

subject gapless sentences.

On the other hand, it seems clear in our data that subcategorization

information guides the parser in the processing of long distance

dependencies. Note that experimental sentences such as (10) in which

there is a transitive verb in the embedded clause, display a clear

priming effect of their antecedents in topic position when compared to

the gapless topic sentences discussed above. This happens presumably

due to the fact that the processor uses the information about the

argument structure of the verb in order to postulate the gap and then

associate it with the filler in topic position. In the gapless cases there is

no empty category to be postulated, once the verbs in the embedded


clause are intransitive. Since there is no gap to reactivate the

antecedent, RT's are longer in the gapless case than in the gap case.

Therefore, our results provide additional evidence in favor of an

"optimal" model of parsing, that is, a comprehension system which has

access not only to syntactic category information, but also to other

types of information, such as argument structure.

3.3.2. The Architecture of the Human Sentence Processing

Mechanism

Therefore, according to our data, topics do not seem to function as

active fillers and the postulation of a gap is not triggered by the

antecedent in A'-position. If this is the case, what is the architecture of

the human sentence processing mechanism (HSPM) that could account

for the BP facts presented above? We want to speculate that the HSPM

deals with the fragment of BP grammar presented above in the

following manner. First the HSPM constructs a surface structure

representation of the sentences, left to right. In the case of the topic

sentences, the topic phrase is represented in a nonargument position. In

the subject sentences this position is left empty. As we have argued

above, the parser has access to information concerning

subcategorization properties of predicates. Therefore upon

encountering a transitive verb the parser expects an object. If there is

not an overt object, a gap is postulated and coindexation with an

antecedent must take place. As suggested by Nicol (1988), the

assignment of coreference is carried on by a coreference module which

constitutes an intermediate stage between purely structural processes

and interpretive processes. This coreference device must determine


which referents are potential antecedents of a referentially-dependent

item in order to access those referents. In the light of the results we

obtained in Experiment 1, we propose that such a coreference device

must have access to information concerning argument/nonargument

positions in the following way. If the parser encounters a pronoun

after the verb, the coreference device will search first for an antecedent

in argument position. If there is not a suitable antecedent in argument

position, then a referent must be found in discourse or in the pragmatic

context. The crucial fact that is clear from our results is that object

overt pronouns in BP "prefer" antecedents in argument position. As a

default strategy, the coreference device looks for an antecedent for the

pronoun at the sentence level as a first resort. If there is not one

antecedent available at this level, then nonargument positions will be

checked. Now, what happens if the processor finds a gap after the

verb instead of a pronoun? In that case, as it is clear from our data, the

coreference device will look for an antecedent in a nonargument

position as the best candidate for coindexation with the gap. Thus, in

the same way as an overt object pronoun triggers the search for an

antecedent within the sentence level, object gaps look for their

antecedents outside the scope of the sentence, in a peripheral position

(A'-position) or even in the context of utterance. In the remnant

paragraphs of this section , we attempt to speculate on possible

cognitive reasons for this processing difference between subjects and

topics.

In the topic-comment type of packaging (Chafe 1976), the speaker

seems to recall a concept which is then commented on. In the subject-


predicate type of packaging, the speaker seems to be also recalling an

event or concept, however this informational item is immediately

integrated into a proposition. At the syntactic level, procedures such as

GF assignment, ø-role assignment, case assignment, etc. are going to

take place in order to license that NP in a well formed sentence. In the

topic-comment strategy, on the other hand, the concept is established

as a generic frame of reference, a set of potentialities of meaning which

may or may not be precised through grammatical operations and

processes at the Sentence level. This peripherical nature of the position

allows the interface between pragmatics and discourse and the

grammaticalities of the sentence. This is is the distinction that Chafe

proposes between the topic as the psychological "subject" of the

sentence and the subject as the proper grammatical "subject" of a

sentence. When we hear a gapless topic sentence such as (12) in BP it

does not seem that we have a surprise effect that would delay the

comprehension of the topic sentence when we find out that the topic

cannot be integrated at the sentence level with the proper GF's, theta-

roles, etc. In the production end, it seems that the speaker has an idea,

but he does not know or want at this instant to make a predication on

this idea that would take it as a specified argument of a proposition.

Rather, he came up with this idea and he makes a comment on it

without having necessarily to fit it into a specific structural slot. The

concept sort of remains activated as "a psychological subject", a source

of interpretive possibilities throughout the sentence. If there is a gap at

the structural level to integrate the topic, a reactivation effect will

happen, as we have demonstrated in the experiment. The speaker may

refer back to this concept, by means of a gap, an overt pronoun or an


NP which in BP may even be the same as the topic alluded to. If the

hearer tried to integrate the topic at once, it would be licit to expect that

the RT's for gapless topic sentences would be higher than RT's for

equivalent "gapless" subject sentences, since as we have already noted,

there would be a "surprise effect" for the former only. Topics are

concepts which get lexicalized (or not, consider the possibility of null

topics), but which have a minimum degree of grammaticalization.

Notice the existence in BP of gapless topics, PP topics with chopped

preposition, etc,. These facts become even clearer if we consider that

topics seem to occur mostly in the flow of spontaneous and colloquial

discourse and less in carefully planned and organized speech (Pontes,

1987). Therefore the best candidates for topic anaphora are empty

categories, since these elements do not carry any definite inflectional

markings, such as pronouns do. Even in terms of the content of their

referents, they do not necessarily retrieve any specific and definite

entity, since they can always have an arbitrary or pragmatic

interpretation. It is thus legitimate to suppose that gaps are more

natural anaphoric means to retrieve topics than overt pronouns, since

they do not commit themselves to inflectional features, such as

pronouns do. Therefore, overt pronouns and gaps seem to differ in

terms of their recoverability capacities. While pronouns will recover

grammatical features such as gender, number, case etc., which have

usually been grammaticalized in the subject position, gaps are simply

structural slots, placeholders for antecedents. In other words, overt

pronouns and gaps adopt distinct types of anaphoric strategies:

whereas the overt pronoun requires the matching with certain

grammatical features, gaps do not. Thus pronouns just go better with


arguments, because these have already been adequately

grammaticalized in the sentence and gaps are the best retrievers for

topics, given their usual low degree of grammaticalization. Notice that

this low level of grammaticalization of topics might even be a

characteristic of their nonargument position, in which no case, theta-

roles or grammatical functions are assigned. It may also be the case

that the preference for zeros as anaphoric devices to make reference to

topics is an on-line processing strategy used by the language processor

in production in order to avoid identificational errors which might

arise as a result of mismatch of feature agreement.

It is interesting to note that this processing default strategy which we

are proposing to account for the ability of zero anaphora to display

higher levels of reactivation of its topic antecedent than the overt

lexical pronoun actually provides a partial explanation for Givón's

(1983) scale of phonological size. In his speaker-hearer neutral study

of topic continuity in discourse Givón notes that zero anaphora is

more used cross-linguistically as a grammatical device to identify topics

than other other coding devices with increasing phonological size.

Givón proposes that a basic principle of iconicity underlies this scale of

phonological size: "the more disruptive, surprising, discontinuous or

hard to process a topic is, the more coding material must be assigned to

it" (p.18). In turn, Givón continues, this principle may translate into a

more generic psychological principle: "expend only as much energy

on a task as is required for its performance" (p.18). If the proposal we

developed above is right, it provides a more straightforward

psychological content for Givón's principles: gaps are better retrievers


of topics than overt pronouns because they have different

recoverability properties. In any case, regardless of how these facts

are processed, the very observation that there are such differences in

the anaphoric selectional properties of gaps and overt pronouns is a

clear indication that even though both elements seem to behave

syntactically as pronominals, they do have different interpretive

properties. In Experiment 2 the interpretive differences between the

empty and the overt pronominal objects in BP will be investigated in

the light of Montalbetti's Overt Pronoun Constraint (OPC).

3.4. Conclusion

In summary, Experiment 1 allows the following conclusions:

a) BP facts support the view that the human sentence comprehension

mechanism is guided by structural considerations. There seems to be a

processing distinction between subjects and topics which can possibly

be related to elements which occupy argument position versus

elements which occupy a nonargument position.

b) Topic bound object gaps in BP are psychologically real in the sense

that they allow a faster reactivation of their antecedents. Subject-bound

object gaps are either not psychologically real in BP or if real they are

interpreted as arbitrary and do not allow a specific and definite

interpretation.

c) Subcategorization information is rapidly accessed in BP sentence

parsing. Unlike the prediction of the Active filler hypothesis (Frazier,

83), information about the predicate argument structure and not

about the antecedent triggers the postulation of a gap in BP topic

sentences.


d) A processing explanation is proposed in order to account for Givón's

et alii (1983) crosslinguistic finding that zero anaphora is a more

common grammatical device for the identification of topics in discourse

than stressed/independent pronouns.

4. Experiment 2: the Interpretation of Object Anaphora in BP

The results of Experiment 1 strongly suggest the existence of different

interpretive properties between the overt pronoun and the empty

category in object position in Brazilian Portuguese (BP): overt pronouns

reactivate subjects but not topics and gaps reactivate topics but not

subjects. These results seem to provide processing confirmation to the

Overt Pronoun Constraint (Montalbetti (1984)), which predicts that

overt pronouns seem to be restricted to the coreferential reading

whereas empty categories can display a bound pronoun

interpretation. In Experiment 2, the difference between the

coreferential vs. bound readings in BP is further investigated by

comparing the possibility of the strict and sloppy readings for overt

and nonovert pronouns in object position.

In certain constructions, pronouns which have non quantificational

NP's as antecedents can display either a coreferential or a bound

reading. Thus (13) can be interpreted as either (13a) or (13b):

(13) John thinks that he caught a fish and so does Peter.

(13a) John thinks that John caught a fish and Peter thinks that John

caught a fish.


(13b) John thinks that John caught a fish and Peter thinks that Peter

caught a fish.

(13a) indicates that the pronoun "he" in (13) is interpreted in a strictly

coreferential sense whereas (13b) constitutes what Ross (1967) called

the sloppy identity of the pronoun. As pointed out by Montalbetti

(1984), the strict reading in (13a) is obtained on purely coreferential

grounds: the reference of "he" is established by assigning to it the value

"John" both in the first and in the second conjunct. However, in order

to obtain the sloppy reading in (13b) we must assume that the first

conjunct of (13) contains an open sentence of the form: x thinks that x

caught a fish. This open sentence is satisfied by "John" in the first

conjunct and by "Peter" in the second, indicating that some form of a

variable binding process is taking place in order to obtain such reading.

Let us consider now a BP sentence such as (14):

(14) A professora encontrou o irmão no mercado e a advogada também

encontrou ele/[e].

"The teacher met (her) brother in the market and the lawyer also met

him/[e]"

If the OPC holds for BP we should expect the construction with the

overt pronoun ele "he" to allow only the strict reading in (14a) whereas

the construction with the null object should also be able to allow the

sloppy interpretation in (14b).


(14a) A professora encontrou o irmão dela e a advogada também

encontrou o irmão da professora.

"The teacher met her brother and the lawyer also met the teacher's

brother."

(14b) A professora encontrou o irmão dela e a advogada também

encontrou o irmão da advogada.

"The teacher met her brother and the lawyer also met the lawyer's

brother."

Two notes are in order. First notice that the experimental sentences

were deliberately designed with an implicit possessive argument of an

inalienable possession rather than with an overt possessive, following

the most natural usage in colloquial BP. That is, the implicit

possessive construction with the definite article (e.g. o irmão "the

brother" ) was used instead of the construction with the overt

possessive pronoun (e.g. seu irmão "her brother") or with the analytic

genitival form of the type "de + N" [of +N] (e.g. o irmão dela "the

brother of hers"), since the implicit possessive construction is the

preferred strategy in colloquial BP. Secondly, notice that the

continuation sentences make a distinction between one entity (the

strict case) vs. two entities (the sloppy cases). Thus, in the

experimental sentences , the continuation sentence with the strict

interpretation was construed as, for example, O irmão de Helena e José

estava no mercado "Helena and Jose's brother was in the market" , that is

presupposing the existence of only one entity (one brother), regardless

of the fact that this entity could be related both to Helena and José.


The continuation sentence with the sloppy interpretation, on the other

hand, was construed as O irmão de Helena estava no mercado e o de José

também "Helena's brother was in the market and Jose's too",

establishing the existence of two different entities (two brothers). Since

the main objective of the experiment was to check if indeed we should

expect the construction with the overt pronoun ele "he" to allow only

the strict reading and whether the construction with the null object

should also be able to allow the sloppy interpretation, we considered

that the difference between one entity vs. two entities would be

appropriate to establish the distinction. Indeed as we discuss below,

the results of experiment 2 indicated that the construction with the null

object is ambiguous between the two readings (one entity vs. two

entities) whereas the construction with the overt pronoun allows only

the strict reading (one entity).

4.1. Method

In this section we describe the participants, the materials and design as

well as the testing procedures used in the experiment.

4.1.1. Participants

20 brazilian USC undergraduate or graduate students volunteered to

serve as participants. They all spoke BP as their first language and had

normal hearing and normal or corrected eye sight.

4.1.2. Materials and Design


The stimuli were 4 sets of 24 two-sentence Experimental passages.

Each subject was presented one of these experimental sets embedded

in an extra set of 46 two-sentence filler passages and 4 two-sentence

practice passages. Each experimental set was made up of 4

conditions with 6 passages per condition in a 2x2 type of design. The

first sentence in each passage ended with either an overt pronoun or

with a gap. The second sentence was a continuation sentence with

either a strict interpretation or a sloppy interpretation of the first

sentence. Notice that although sentences were very similar, differing

only in terms of the tested variables, they were distributed between

subjects, so that each subject saw only one version of each sentence

type. The distribution of sentence types in 4 sets allowed all sentences

of a type to be compared.

4.1.3. Procedures

In order to assess BP speakers' interpretative preference intuitions

concerning these constructions, Experiment 2 uses a measure which is

a unimodal auditory adaptation of the method employed by

Kurtzman & MacDonald (1993) in their study of quantifier scope

ambiguities. Subjects hear sentences such as (15) or (16) followed by

the auditory presentation of a continuation sentence such as (a) or (b).

Participants then are asked to judge whether the continuation sentence

is indeed a reasonable continuation of the first sentence. For example,

for (15) and (16) the continuation sentence would be either ( a) or ( b):

(15) O Pedro castigou a filha e a Maria também castigou ela.

"Pedro punished (his) daughter and Maria also punished her."


(16) O Pedro castigou a filha e a Maria também castigou [e].

"Pedro punished (his) daughter and Maria also punished [e].

(a) A filha de Pedro e Maria se portou mal. (strict reading)

"Pedro and Maria's daughter misbehaved."

(b) A filha de Pedro se portou mal e a de Maria também. (sloppy

reading)

"Pedro's daughter misbehaved and so did Maria's daughter."

If the OPC holds in BP only the (a) sentence should be judged as a

reasonable continuation for the sentence in (15), since, according to

Montalbetti's generalization, the sloppy reading should not be available

for the overt pronoun. For sentence (16), both the sloppy reading in (b)

and the strict reading in (a) should be possible.

Right after the presentation of the second sentence a question mark

would show in the CRT screen. At this point subjects indicated

whether or not the continuation sentence was a reasonable discourse

continuation of the first sentence by pressing a yes or a no key in a

button box. Response times were measured. Following four practice

trials, experimental and filler sentences were presented in a different

random order to each participant. Subjects were tested individually in

sessions of approximately 15 to 20 minutes and generally reported in

post-session interviews that the task was at least moderately easy.


4.2. Results

The extent to which continuation sentences were judged compatible

with the anaphor sentences is presented in Table II and displayed in

Figure 2.

TABLE II. Compatibility judgments (%)

Condition % acceptance

Null Strict (nst) 88 %

Null Sloppy (nsl) 89 %

Pronoun Strict (pst)

Pronoun Sloppy (psl)

94 %

36 %

nst nsl pst psl0

20

40

60

80

100 % compatible judgment%incompatible judgment

Judgment %

Condition

% ju

dgm

ent

FIGURE 2. % Judgment

For the null object sentences, participants judged both the

continuation sentences with a strict interpretation (NST) and the

continuation sentences with a sloppy interpretation (NSL) as

compatible. For the overt pronoun sentences, an effect between the


strict vs. sloppy readings obtained. Subjects judged the continuation

sentences with a strict interpretation (PST) as compatible with the

overt pronoun first sentences, but they judged the continuation

sentences with a sloppy interpretation (PSL) as incompatible in 64% of

the cases. This pattern produced a robust anaphor X interpretation

interaction, [F (1,19) = 51.1, p < .05] .

nst nsl pst psl0

1000

2000 YESNO

Judgment Latencies

Condition

Res

pons

e T

ime

(mse

c)

FIGURE 3. Reaction Times for yes and no answers to continuation

sentences

Figure 3 compares the response times for the judgment task.

Participants took in average one second to say yes to the NST, NSL

and PST continuation sentences, but in those 36 % of the observations

which judged the PSL continuation sentences as compatible,

participants needed in average 800 ms more to reach their decision. For

the null object, there is a nonsignificant response times difference of

only 50 ms. between those who accepted the strict interpretation (NST)

and those who accepted the possibility of the sloppy interpretation


(NSL). However, for the overt pronoun, there is an RT difference of

more than 900 ms. between the acceptance of the strict and of the

sloppy interpretation. Since there were 5 subjects out of the 20 who

took the experiment who either did not give any yes answer to the

possibility of the sloppy interpretation of the overt pronoun or who

took too long to reach their decision (above the 2.0 Standard Deviation

cutoff point), there were empty cells in the data set which made it

impossible to calculate the ANOVA here. Nevertheless, the RT

difference of over 800 ms. seems to indicate that those few subjects who

did accept the possibility of the sloppy interpretation displayed a

considerable degree of hesitation to reach their decision.

4.3. Discussion

In Experiment 2, the difference between the coreferential vs. bound

readings of overt and empty anaphors in BP was further investigated

by comparing the possibility of the strict and sloppy readings for overt

and nonovert pronouns in object position. Subjects tested in a speeded

judgment task showed a preference for the strict interpretation of the

overt pronoun, whereas the null object construction is also able to allow

the sloppy interpretation. Thus, Experiment 2 clearly supports the

hypothesis that the sloppy interpretation is not available to the overt

pronoun, as predicted by Montalbetti's generalization.

5. General Discussion

In section 3, we presented experiment 1, which established the central

facts in the study: the empty category in object position reactivates its

subject antecedent but not its topic antecedent whereas the opposite

configuration holds for the overt lexical pronoun. We argued that our


experimental results clearly teased apart the A-bound from the A-bar

bound null objects and revealed that the overt lexical pronoun does not

have the ability to reactivate its topic antecedent. Additionally, we

argued that our experiment demonstrated that topic-comment

constructions in BP are processed as readily as the subject-predicate

type. We also showed that the results of Experiment 1 provided

partial psychological justification for Givón's scale of topic accessibility

and suggested a processing explanation to the observed difference in

reactivation properties between the empty and the overt elements: a

default, first resort parsing strategy in the referent search process

which makes empty categories the ideal retrievers of topics. We finally

claimed our experiment to be informative with relation to several

theoretical psycholinguistic issues: the psychological reality of gaps,

the role of grammatical structure in the priming process, the effect of

the global topic of discourse in reference resolution, the rapid access

by the human parser to information on the argument frames of

predicates.

Finally, in section 4, we further investigated the results of experiment

1 in the light of Montalbetti's generalization: the fact that in several

Romance languages overt pronouns cannot be locally A-bar bound, but

empty categories can (Montalbetti, 1984). We articulated an evaluation

of the applicability of Montalbetti's generalization in BP and presented

experiment 2 which provided further confirmation to the interpretive

distinction between overt and nonovert elements in BP : unlike the

empty category, the overt lexical pronoun in object position in BP

cannot be assigned a sloppy identity.


Therefore, our research provided strong processing evidence to the

claim that empty categories and overt pronouns display important

syntactic and semantic differences. As it was demonstrated in

experiment 1, a strictly syntactic difference in behavior bettween

empty and overt elements was captured in a priming paradigm: nulls

were shown to reactivate topics and overts were shown to reactivate

subjects. In experiment 2 , nulls and overts were also shown to differ on

semantic grounds: the sloppy interpretation is not available to overt

pronouns.

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