Anaphoric Resolution of Singular and Plural Pronouns: The Reference to Persons Being Introduced by Different Co-ordinating Structures

Transcription

1 Journal ofsemantics 7: N.I.S. Foundation (1990) Anaphoric Resolution of Singular and Plural Pronouns: The Reference to Persons Being Introduced by Different Co-ordinating Structures MARTINA HIELSCHERandJOCHEN MUSSELER Univeristy ofbielefeld Abstract For the resolution of plural pronouns referring to singularly introduced reference persons the plural antecedent has to be built up by the cognitive system itself (installing a plural complex, e.g. 'John wanted to have a picnic with Mary. They had...'). For singular pronouns the antecedent is usually mentioned in the text explicitly. This contribution examined which aspects of the prepronominal sentence structure determine the installation of a plural antecedent and at which point of time this process is initiated. Using the German pronoun 'sie', which is ambiguous in respect to number, it was shown in a first experiment that subjects have a preference to continue a text by referring to both singularly introduced persons, if they are combined by the conjunctions 'and', 'as well as' or neither/nor', or by the preposition 'with', if the female person is in the verb phrase. Subjects prefer to refer to the female person only after the prepositions 'without' and 'instead of, and after 'with' if the female person is in the noun phrase. The reaction time data of the second experiment indicated that at least these conjunctions and 'with' initiate a plural reference complex before a pronoun is read. This pre-pronominal installation of a complex serves to facilitate plural reference operations executed at a later point in processing. In our view, pronominal resolution is more than a mere recursive search-andmatch procedure initiated by reading the pronoun; the cognitive system is better prepared for processing further referential relations. This view is discussed in the context of a 'pronominal occupation' hypothesis. INTRODUCTION The comprehension of pronouns confronts the cognitive system with the problem of identifying the concept to which the pronoun refers in the preceding or following text (for recent surveys sec, for example, Sanford & Garrod 1989; Miisseler & Terhorst 1990). In written language, pronouns are most frequently used anaphorically, i.e. referring to concepts that were mentioned earlier in the sentence or in one of the preceding sentences. Relevant determinants for the process of anaphoric pronominal resolutions are, for example, gender and number of the pronoun (Ehrlich 1980), as well as 'topic' or main character (Marslcn-Wilson, Levy & Tyler 1982) and verb inflexion (Garrod & Sanford 1985). Most of these studies refer to singular pronouns; only

2 348 Anaphoric Resolution of Singular and Plural Pronouns a few refer to plural forms (Garrod & Sanford 1982; Moxey & Sanford 1988; Eschenbach, Habel, Herweg & Rehkamper 1989). This article deals with the effect of six co-ordinating structures combining several referents (i.e. conjunctions and prepositions) on the resolution process of singular and plural pronouns. First of all, there is no reason to assume qualitatively different mechanisms with regard to the resolution processes for singular and plural pronouns. However, the resolution of singular pronouns may be easier than the resolution of plural pronouns. Successful search for a singular referent provides a concept which always corresponds on number and gender of the pronoun: (1 a) Mary undjohn wollten picknicken. (Mary and John wanted to have a picnic.) (ib) ErmufitezundchstdieZutaten einkaufen. (He 1 had to buy the picnic supplies first.) As opposed to singular pronouns, there need not be a correspondence in gender and number between plural pronouns and their referential concept. For example, if there are two singular concepts introduced in a noun phrase coordinated by the conjunction 'and', then the pronoun 'they' (German 'sie') can be used to refer to the two singular objects as a plural entity, as the following example shows: (2a) Mary undjohn wollten picknicken. (Mary and John wanted to have a picnic.) (2b) Sie mufiten zundchst die Zutaten einkaufen. (They had to buy the picnic supplies first.) Note that in German the meaning of the pronoun 'sie' is ambiguous. 'Sie' can refer to just 'Mary' or to both 'Mary and John'. Only the verb inflexion determines the reference to the singular ('Mary') or plural concept ('Mary and John'). Additionally, in the German example there is at least a correspondence in number of the verb inflexions ('wollten' and 'mufiten') used in the two sentences. This is not the case if the two singular concepts are introduced with a preposition in the noun and verb phrase yielding different verb inflexions ('wollte' and ' (3a) John wollte mit Mary picknicken. (John wanted to have a picnic with Mary.) (3b) Sie mufiten zundchst die Zutaten einkaufen. (They had to buy the picnic supplies first.) Obviously, for comprehension of examples (2) and (3) the reader has to combine the singular persons in such a way that one can refer to them as to a whole plural entity that fits the plural pronoun. We will refer to die process

3 M. Hielscher andj. Miisseler 349 that yields such a plural entity as 'installing a complex' (for a formal description see Eschenbach, Habel, Herweg & Rehkamper 1989). 'Installing a complex' should not necessarily be interpreted as building a whole new entity (which may be of semantical or syntactical nature): it can be interpreted as installing a plural address with pointers to the singular objects as well. In a near sense this second interpretation does not describe an installation process as no new representational objects need to be built in which both objects melt together (eventually by losing their individual identity), but the term is adequate if it is understood to describe the referential accessibilities for a plural pronoun. The process of installing a complex is an additional component in the text comprehension process, which should take additional time over the resolution of a singular version. The following experiments use the ambiguous meaning of the German pronoun 'sie' to investigate differences between singular and plural anaphoric pronominal resolution. The texts we used allowed both a plural and a feminine singular interpretation. In every case a female and a male person arc introduced, combined by different co-ordinations: 'and', 'as well as', 'neither/nor', 'with', 'without', and 'instead of. Firstly we tested our intuition about the preferred pronominal interpretation following these different co-ordinations. Preferences for a singular or plural interpretation should lead to a more frequent use of singular or plural verb forms respectively in a sentence completion task. However, with a sentence completion method it is impossible to determine the exact point in time at which the complex is installed during text processing. To reveal information about this point in time a second experiment was conducted using an on-line reaction time measure. EXPERIMENT 1 The first experiment was designed to investigate semantic preferences for a singular or plural interpretation of the German pronoun 'sie'. Subjects had to read sentences with a female and a male person co-ordinated by the conjunctions 'and', 'as well as', and 'neither/nor', or the prepositions 'with', 'without', and 'instead of. The following sentence beginning with 'Sie...' was continued by the subjects in a sentence completion task. It can be assumed that a plural interpretation of the pronoun 'sie' is preferred for the three conjunctions and similarly for 'with'. These four express something that the two persons have in common or do together; building a complex of these two persons should therefore be suggested semantically. In this case the plural should be used more frequently. 'Without' and 'instead of express a difference between the two persons: one does something without or instead of the other. For these two prepositions it is assumed that no complex should be

4 350 Anaphoric Resolution of Singular and Plural Pronouns semantically suggested, or that at least the singular concepts will stay in focus. Therefore a singular interpretation of the pronoun will be preferred, i.e. a singular verb will be chosen more frequently to complete the sentence. In addition we looked at the sequence introducing the two persons which is seen as a possible intermediating factor ('John with Mary' versus 'Mary with John'). In line with the results of Gcrnsbacher & Hargreaves (1988; sec also Miisseler & Rickheit 1990a), we assume that the first position which they call 'advantage of first mention', is important. Consequently, a feminine singular interpretation of the pronoun 'sie' should be more likely if the female person were mentioned in the first position. 2 Texts Method Experimental texts were designed according to the schema already mentioned: setting (s) Die Hitze war unertrdglich. (The heat was unbearable.) co-ordination (c) John undmaryschwammen im See. (John and Mary were swimming in the lake.) pronoun (p) Sie... (She/They...) o, 1, or 2 setting sentences (s) at the beginning give a general description of the setting, but without mentioning either of the two persons. The following sentence (c) introduces them by their Christian names, in each case a female and a male person, combined by one of the co-ordinations mentioned above (Table 1). Design As it is possible in German to continue the sentence (c) with a plural or a singular verb form after die co-ordinations 'as well as' and 'neither/nor', these two versions were separated. This resulted in eight different co-ordinativc structures that had to be examined: 'and', 'as well as (sg)\ 'as well as (pi)', 'neither/nor (sg)\ 'neither/nor (pi)', 'with', 'without', and 'instead of. As a further independent variable we distinguished the sequence of introducing the female and the male person varying on two levels ('female-male', versus 'malefemale', e.g. 'Torsten competed with Ina' versus 'Ina competed with Torsten'). Thus, we had two different text types with the critical variation in the co-ordinating sentence (c) for each co-ordination.

5 M. Hielscher and J. Miisseler 3 51 Table 1 One example for each co-ordinating structure used in the sentence completion task Co-ordination Example 'and' Die Hitze war unertraglich. Fritz und Erna schwammen im nahegelegenen See. Sie... (The heat was unbearable. Fritz and Erna were swimming in the nearby lake. They/She...) 'as well as' Der Motor hatte plotzlich ausgesetzt. Sowohl Karl als auch (sg/pl) Gabi bastelte/bastelten an dem Motorad herum. Sie... (Suddenly the engine had broken down. Karl as well as Gabi tried to repair the motor-bike. They/She..) 'neither/nor' Gestern war die Abschlufipriifung. Weder Uwe noch (sg/pl) Agnes war/waren zu der Priifung erschienen. Sie... (The terminal examination was yesterday. Neither Uwe nor Agnes came to examination. They/She...) 'with' 'without' 'instead of Procedure Die Fahrradtour fiiihrte aufs Land. Torsten machte mit Ina ein Wettrennen. Sie... (The bicycle tour passed through the countryside. Torsten competed with Ina in a race. They/She...) Die Ausstellung war gut organisiert. Anton war ohne Petra ins Museum gegangen. Sie... (The exhibition was well organized. Anton came to the museum without Petra. They/She...) Morgen ist die Geburtstagfeier. Statt Werner backte Elli den Geburtstagskuchen. Sie... (The birthday party is tomorrow. Instead of Werner Elli made the bithday cake. They/She...) Questionnaires were constructed which included one text of each of the 16 text types and 16 distractors in a random sequence. Distractor texts were constructed following the same reasoning as the experimental texts; they did not start with 'Sie...' in the sentence (p), but with another pronoun or noun referring to one of the concepts mentioned in the preceding sentence. Thus, each questionnaire consisted of 32 small texts. Subjects were instructed to read each text thoroughly and then continue the last sentence spontaneously in written form.

6 352 Anaphoric Resolution of Singular and Plural Pronouns Subjects Sixty-four students from different departments of the University of Bielefeld took part in the experiment. Their mother tongue was German. They were paid for participation. Results and discussion Only fully answered quesrionnaires were entered into the data analyses; that left 60 quesrionnaires. For each of the 16 text types frequencies of plural versus singular completions % 2 -tcsts were peformed (Table 2). The results show that a plural sentence completion is preferred after introducing the two people co-ordinated by 'and', 'as well as', and 'neither/nor', all three being independent of the sequence in which the referents were introduced in sentence (c); 'as well as' and 'neither nor' are also independent of the verb inflexion. For the preposition 'with' results show a preference for the plural interpretation when the female version is introduced in the second position, i.e. in Table 2 Frequencies of singular versus plural sentence completions depending on sequence of introducing a male and a female person, and on co-ordinating structure Co-ordination and as well as (sg)) (Pi) neither/nor (sg) with without instead of (Pi) Position" f-m m-f f-m m-f f-m m-f f-m m-f f-m m-f f-m m-f f-m m-f f-m m-f Singular Plural ' X 2 (df- i) b 38.4"' 45-1"* "* 38.4'" 48.6'" 38.4"* 29.4"* 41.7'" 52-3"* 11.3*" 6.7" i'" 48.6"' 60.0"* " Sequence of introducing the two persons, female person-male person (f-m) versus male pcrsonfcmalc person (m-f). b Level of significance: **V < 0.001, **p < 0.01.

7 M. Hielscher and J. Miisseler 353 the verb phrase. But in the case of the female person being introduced in the first position, i.e. in the noun phrase, the singular interpretation is preferred. A singular sentence completion is preferred after introducing the two persons co-ordinated by 'without' and 'instead of, again independently of sequence. To summarize, using the sentence completion task, we found a preference for a plural interpretation of the pronoun 'sie' following the three conjunctions, and a preference for a singular interpretation following the prepositions 'without' and 'instead of. For 'with' we found a dependency of preferred interpretation on sentence position of the female person. In line with the argumentation of Sanford & Garrod (1989), our results indicate that readers can use quite different information from the text to determine the pronominal referent, even in formally ambiguous structures. They use semantic information of the various conjunctions as well as sentence position. Following these results, one can assume that a plural reference complex has been installed for the conjunctions, and in part for 'with'. Nevertheless, with the sentence completion technique the temporal course of building a plural reference complex is not explicitly determined. It provides only the tendency to complete a sentence referring to one or both persons after reading 'sie\ No accurate information is contributed about the point in time of the discourse processing at which the complex is installed and is an available part of the text representation; it is not necessarily the point in time when the pronoun 'sie' (Miisseler & Rickheit 1990a) is read. This is the central question now in the main experiment using an on-line reaction-time measure. EXPERIMENT 2 There arc three possibilities for the resolution process of plural pronouns: Firstly, one can argue that the plural complex is not installed before it becomes unavoidable in the text reception. In a sentence like example (2a) or (3 a) there is no need to build a plural complex of both persons. However, as soon as one reads the pronoun 'sie', followed by a plural verb in the next sentence (2b) or (3b), the pronoun has to be related to both 'John and Mary' and at this point the complex has to be built. In this case the pronominal resolution is a recursive search-and-match procedure as described by Clark & Sengul (1979), Hirst & Brill (1980), Garrod & Sanford (1982), Corbett & Chang (1983), Sanford (1985), Matthews & Chodorow (1988), and Miisseler & Terhorst (1990). The complex is triggered by reading the pronoun, in case of ambiguity by reading the pronoun plus plural verb form. A search of the preceding sentence yields no plural objects to which the pronoun can be related. A plural reference complex has to be installed from possible singular concepts. One can assume

8 354 Anaphoric Resolution of Singular and Plural Pronouns that, in contrast to the resolution of a singular pronoun, the processing time of the plural pronoun should be increased by the additional phase of building a reference complex. Correspondingly, hypothesis i claims that the singular pronoun is processed more quickly than the plural pronoun. An alternative prediction implies that building the complex is independent of reading the pronoun. The plural complex is installed while reading the first sentence, initiated by the co-ordinating structure. In this case, there arc two possible alternatives for the pronominal resolution process: the first claims that the singular concepts stay in focus together with the plural complex. Then the singular concept fits the pronominal resolution just as well as plural one. No processing time differences should occur (hypothesis 2a); the second claims that with installing the plural complex the singular concepts are deactivated, which can mean that they stay in focus but that the plural concept is marked and more easily accessible than the singular entities, or that they are no longer represented in focus at all; both alternatives lead to a preference for plural interpretations in the following text. In this case a rc-activation or a re-focusing of the singular concept is necessary for the resolution of the singular pronoun. This additional cognitive mechanism should be expressed in a processing time disadvantage for the singular pronoun (hypothesis 2b). Experimental evidence for one of these hypotheses should depend on the preposition or conjunction used. Results from preceding experiments (Miisseler & Rickheit 1990a) suggest hypothesis (2b) to be adequate for 'and', and partially for 'with' (in a sentence structure with the female person in the second position, i.e. the verb phrase). Under the additional assumption that a plural preference requires a formerly installed complex, the results from Experiment 1 suggest the installation of a plural complex to be pre-pronominal and marked for the conjunctions 'as well as' and 'neither/nor', too. This hypothesis is not necessarily adequate for the disjunctive structures 'without' or 'instead of and for 'with' in a sentence structure where the female person is in first position (i.e. the noun phrase). For these co-ordinating structures, results from Experiment 1 showed a preference for a singular interpretation of the pronoun l sie', which might indicate that the singular concepts remain marked. In order to test the procedural hypotheses as they were elaborated above for the different co-ordinating structures, an experimental on-line technique with a semantic decision task was used. Texts Method Four-sentence texts were constructed following the same pattern as in Experiment 1:

9 M. Hielscher andj. Miisseler 355 setting (s) Die Hitze war unertrdglich. (The heat was unbearable.) co-ordination (c) John and Mary schwammen im nahegelegenen See. (John and Mary were swimming in the nearby lake.) pronoun (p) Sie hatten/hatte* in der letzten Woche Schwitnmengelernt. (They/She had learnt to swim in the last week.) end (e) Besonders Mary* war noch sehr vorsichtig. (Mary was especially very cautious.) The critical sentence (p) with the pronominal reference was presented in a singular or a plural form after the co-ordinating sentence (c). The verb inflexions ('hatten' versus 'hatte') definitely indicated which interpretation of 'sie' was adequate. The sentences (e) were optional depending on how many setting sentences (s) were presented. Design The critical pronominal parts of the texts in sentence (p) differ with regard to the pronoun 'sie' referring to a singular or a plural concept of the preceding text ('pronoun') for each of the co-ordinating structures used in Experiment i. + The second independent variation again refers to the sequence of introducing the referents in sentence (c) ('male-female' versus 'female-male'). All conditions were presented to every subject in randomized order. Procedure Altogether, 96 texts were presented to every subject in blocks often. After each block of texts subjects had the opportunity to take a break. In order to control the reading process the texts were presented to the subjects word-by-word on a computer screen with the moving-window technique. First, masks were presented on the screen in which every letter is replaced by an V; blanks and punctuation marks remained unchanged. Such masks serve to facilitate the eye fixation behaviour of the subjects. Then, with a step rate of 408 ms, each mask was replaced by the whole word until the complete sentence was shown. Next, the sentence was re-masked again for 408 ms to facilitate eye movements to the beginning of the next line; then the following sentence was presented in the new line. The text presentation halted at the critical position for the referential resolution (after 'Sie' plus verb form), marked by * in the example. As soon as the text was stopped, a square appeared beneath the text. This was the signal for the subjects to decide whether one or two persons were involved in the current sentence. They answered by pressing the left or the right button, respectively. 5 The subjects received feedback as to whether or not their answer was correct.

10 356 Anaphoric Resolution of Singular and Plural Pronouns Altogether, subjects received 96 texts. Each text stopped at the critical text section, and 96 additional stops were introduced at other text passages, serving as distractors. Two seconds elapsed between presentations of the single foursentence texts. Subjects Thirty-three students from different departments of the University of Bielefeld volunteered for this study. Their mother tongue was German. They were paid for their participation. Results and discussion One subject was excluded from further statistical analysis because of an error rate higher than 15%. For the remaining 32 subjects the mean error rate was 4.2%. The reaction times for these wrong decisions were replaced by the mean reaction time for each subject under the specific combination of conditions. The data were entered into two ANOVAs for each co-ordination, one with 'subjects' and one with 'texts' as the random factor. 6 For the three conjunctions 'and', 'as well as', and 'neither/nor' both analyses, over subjects and over texts, showed a main effect for the 'pronoun' factor: the decision time for the pural pronoun was about 40 ms shorter than for the singular version (Figure 1). For 'and' the effect was significant, with P < 0.05 in both analyses (F s (i,31) 6.34, (MS e and F t (i,n) , MS e ). For 'as well as' there was the same tendency in both analyses with P < O.IO (F s (i.3i) , MS e = and F t (i,n) , MS e ). For 'neither/nor' again a significant main effect was found, with />< 0.05 in both analyses (F s (i.3i) 7.92, MS e = and F t (i,u) = 4.76, MS t ). There was no main effect for 'sequence' and no significant interactions. These results suggest that hypothesis (2b) is correct for the three conjunctions, i.e. a complex is installed while reading the first sentence, unrelated to the need to later refer to the plural entity. Semantically the three conjunctions seem to trigger building a plural reference complex while reading the sentence (c), thereby deactivating the single concepts so that the reference to a singular concept needs 're-focusing or re-activation', which takes additional time. For the three prepositions 'with', 'without', and 'instead of there were no main effects of factors 'pronoun' and 'sequence' but significant interactions for 'with' (F s (i,3i) 6.25, MS e , p<o.o5, and F t (i,n) 8.83, MS C ), p<o.o5), and for 'instead of (F s (i,3i) = 4.23, MS t , p<o.o5, and F t (i,n)= 3.14, MS C -= , P<O.IO). As

11 M. HielscherandJ. Miisseler ~ 'and' Sequence Bli Male-female lixjljj Female-male 'as well as' Sequence - 'neither/nor' Sequence Singular [ j Male-female fil-l-i-] Female-male I ] Male-female $:-Zi\ Female-male Pronoun S'A Plural Figure 1 Mean reaction times to a singular or plural pronoun for the co-ordinations 'and', 'as well as', and 'neither/nor', introducing the female person firstly (f-m) versus the male person firstly (m-f) Figure 2 shows, the plural interpretation is preferred if the female person is in the verb phrase, that is, the second position for 'with' ('John with Mary...') and the first position for 'instead of ('Instead of Mary John...'). The singular interpretation is preferred at least for 'instead of if the female person is in the noun phrase, i.e. the second position (instead of John Mary...'). This

12 358 Anaphoric Resolution of Singular and Plural Pronouns _ 'with' Sequence 111 Male-female Effivij Female-male J 740 J, o 680 _ S 660 a ct 'without' i 1 i _ 'instead of Singular Sequence j Male-female [: : :] Female-male Sequence ] Male-female v.vj Female-male Pronoun Plural Figure 2 Mean reaction times to a singular or plural pronoun for the conjunctions 'with', 'instead of and 'without', introducing the female person firstly (f-m) versus the male person firstly (m-f) correspondence possibly indicates that the syntactic function is the more relevant factor for marking a singular person (Grober, Beardsley & Caramazza 1978; Wykes 1981; Corbett & Chang 1983) than the position in a sentence. Hypothesis (2b) seems to be adequate if the female person is in the verb phrase: a complex is installed and focused. If the female person is in the noun phrase,

13 M. Hielscher and J. Miisseler 359 hypothesis (2a) may be correct for 'with': a complex is built but not marked; and hypothesis (ib) seems to be correct for 'instead of: the singular female person remains marked. For 'without', no effect was found at all. Therefore hypothesis (2a) seems to be adequate to interpret the results: a complex is installed but is not focused, unlike the singular concepts. GENERAL DISCUSSION AND CONCLUSION A brief review of the results from both experiments for comparison shows that the data we obtained using quite different methods are largely compatible. For the three conjunctions used, 'and', 'as well as', and 'neither/nor', results from Experiment 2 clearly showed an advantage for a plural interpretation of the pronoun l sie' in the critical sentence (p). The mean reaction time advantage was about 40 ms. These results supported hypothesis (2b). Comparing these results with the results from Experiment 1 under the additional assumption that a plural preference requires a formerly installed complex, the reaction time advantage was predictable. Here the results of the two experiments are compatible, suggesting that the complex is built triggered by the conjunction before the pronoun is read. The pronoun 'sie' may be in no way ambiguous for the reader in this case (Sanford & Garrod 1989) and will be resolved immediately. The re-activation or re-focusing of the singular concepts when reading a singular verb form afterwards requires additional processing time compared to the plural verb form. The results for the prepositions are slightly more complicated. In Experiment 2 for 'with' and 'instead of an interaction was found between reference to a plural or singular concept, and 'sequence'. Indeed, it seemed to be more the influence of the syntactic function than the sentence position itself. For 'with' a clear reaction time advantage for the plural interpretation was found if the female person was in the verb phrase (hypothesis 2b). No reaction time difference for the singular and plural decisions was found if the female person was in the noun phrase (hypothesis 2a). Comparing the results from both experiments, a small difference is found. Following the results from the sentence completion technique a disordinal interaction was expected, but only a hybrid interaction was found: there was no difference between singular and plural decisions if the female person was in the verb phrase. For 'instead of, the singular interpretation of the pronoun is favoured if the female person is in the noun phrase. This is not the case if the female reference person is in the verb phrase. Here the reaction time for the plural expression decreased. Following these results, one must conclude that hypothesis (2b) is correct for 'instead of Mary John...'. A complex ('John' and 'Mary') is installed and focused. Hypothesis (ib) seems to be correct for 'instead of John Mary...'.

14 360 Anaphoric Resolution of Singular and Plural Pronouns The singular objects remain focused or, in fact, no complex is built For the preposition 'without' no general processing time advantage was found for either the plural pronoun or the singular one. Here hypothesis (2a) seems to be adequate: the complex is built, but the singular and plural concepts have equal rights in the pronominal resolution process. One problem with the results for 'without' and 'instead of is that they arc not in line with the results of Experiment 1. The completion task clearly suggested an advantage for the singular pronoun which was not found in Experiment 2, except for 'instead of with the female person in the noun phrase. One reason could be the methodical problem with the text structure, always introducing two persons, which could have led to a general advantage for the plural decision (see note 4). However, as there were several interactions with advantages for the singular pronoun, this is not a very convincing argument. Instead it might be advantageous to look at the experimental methods we used in more detail. The off-line sentence completion task combines reception and production processes, while the on-line reaction-time technique reflects only a reception measure. Thus, possibly at an early stage of text processing, the singular and plural concepts are both available; consequently, no differences in reaction time measurement of reception were found. However, in the sentence completion task the subjects had to produce a coherent text by themselves. Therefore, they had to look for arguments why, for example, 'Mary withoutjohn...' or 'instead of John Mary visited an exhibition'. It may be easier to produce a coherent text by referring to 'Mary' only. So the singular pronoun was favoured, a tendency that becomes evident in the produced texts. Following this point of view, reception processes are much more flexible than production processes, at least in the context of pronominal resolution. All together, the results indicate that under certain conditions a plural complex is installed before the plural pronoun is read. This facilitates the resolution of plural pronouns. Further, one can argue that the installation of a complex serves to facilitate later reference relations. In this case pronominal resolution is more than a mere recursive search-and-match procedure triggered by reading the pronoun. Such a recursive search-and-match procedure is conceptualized in most of the current theories on pronominal resolution (e.g. Clark & Sengul 1979; Sanford 1985; Garrod & Sanford 1982,1985; van Dijk & Kintsch 1983; Marslen-Wilson, Levy & Tyler 1982; Just & Carpenter 1987). The theories differ both on content and on the underlying processes but agree on the main aspects of the pronominal resolution (Musseler & Terhorst 1990; Musseler & Rickhcit 1990b): their first assumption is that the resolution process starts with the encoding of the pronoun. In the simplest case, the resolution of the pronoun can be realized by the agreement of the gender and number of the pronoun with the reference object. If there is more than one possible antecedent such a

15 M. Hielscher andj. Miisseler 361 simple comparison of gender and number is insufficient. Thus, the second assumption to make is that the cognitive system has to restrict die reference domain. This process can be guided by syntactic, semantic, and textual features of the reference concept. The third assumption conceptualizes pronominal resolution as a search-and-match procedure within the reference domain which establishes the relation between the pronoun and the reference concept (Clark & Sengul 1979; Hirst & Brill 1980; Garrod & Sanford 1982; Corbett & Chang 1983; Sanford 1985; Matthews & Chodorow 1988). In line with Sanford & Garrod (1981: p. 141), our results indicate that the cognitive system is working more efficiently for processing further referential relations. As far as the pronominal resolution is concerned, this preparation could have two effects: first, possible referents are focused or marked in focus by the processing system leading to a simple identification of the antecedent, by searching and matching only a few alternatives. However, the resolution process is triggered after encoding the pronoun, but restricted more to the focused antecedents; this way the search process will be facilitated. Second, an alternative view would be that a search process is not the only possible process for pronominal resolution. In a previous paper (Miisseler & Terhorst 1990) we discussed arguments and evidence for the claim that focused or marked discourse referents activate suitable pronouns as their potential future reference forms; recursive search processes may therefore not be needed in these cases. This pronominal occupation is supposed to be the product of the normal comprehension process and does not require any specialized processes (see Bosch 1988 for a related idea of resolution without search or selection). In terms of a connectionist view, one can say that reading a Christian name activates the pronoun node together with the person concept node; this associated activation of both (or maybe there is only one node representing both concept and pronoun) results directly from their common features, in the first place number and gender. As pronouns are activated prior to encountering the anaphor, no recursive search-and-match is required because the referential links have already been established. In the present experiments there is no direct evidence for the resolution by a facilitated search-and-match or by an occupation procedure. If the reaction times of the plural pronouns would have been increased in each condition and thus would indicate that the installation of the complex was initiated after reading the anaphor, then the recursive search-and-match resolution should be favoured for the plural pronoun. Hence the present results, which are in part opposite, fit both explanations. Other results reported by Sichelschmidt & Gunther (1990) provide evidence for the occupation approach, but further research is necessary to decide which of the two procedures is used by the cognitive system.

16 362 Anaphoric Resolution of Singular and Plural Pronouns Acknowledgements The research reported here was supported by grants from the Deutsche Forschungsgemeinschaft (Ri 314/9). Thanks are due to Julie Carson and Andrea Reuther for many insightful stylistic suggestions. MARTINA HIELSCHER and JOCHEN MOSSELER Fakulta'tfiir Linguistik und Literaturwissenschaft Arbeilseinheit Psycholinguistik Universitdt Bielefeld Postfach 8640 D-4800 Bielefeld 1 FRG NOTES 1 In this case the pronoun can be used. If both persons were of the same gender it would not be possible to use the pronoun in this syntactical structure ('Peter and John wanted to have a picnic. He...'). 2 Note that there is a difference between sentence position and syntactic function. First versus second sentence position is not always the same as syntactic subject versus object. This is only the case for 'with' and 'without'. In German 'instead of is used more usually with an object-subject structure. 'And', 'as well as', and 'neither/ nor' put both people into the noun phrase. 3 The number of analyses is statistically critical, but since the significance is always above (with one exception of 0.01) a type I error is not probable. 4 There is a methodological problem due to the text structure used: in all texts two possible reference persons were introduced, a male and a female one. With regard to the subject's task (one or two persons?), one can argue that the decision 'two persons' is generally favoured. What is measured then would include a general reaction tendency to the global amount of possible reference persons in the texts, always two, which facilitates the resolution of a plural pronoun. The adequate control condition would imply introducing only one possible reference person and referring to it with a singular or plural pronoun. With such texts the problem gets even worse, because in such texts no plural pronoun can be used at all. Thus, if two persons are introduced as opposed to texts where only one person is introduced, then the plural 'sie' becomes even more probable in texts introducing two persons. Thus, we decided to use two persons in all texts and refer to one or both via the pronoun with the same probability, so that the subjects receive no hint as to which decision might be correct, and a preference for the plural decision would be even hindering for the task. However, results have to be interpreted cautiously if the plural decision is facilitated in all texts independently of the variation we used. 5 In this experiment the right button stands for 'two persons' and the left button stands for 'one person', but results of a pilot experiment with reversed answer modus indicate no or at least negligible small reaction time differences. 6 Exactly speaking we conducted 2 X 2-ANOVAs for the co-ordinations 'and', 'with', 'without' and 'instead of. For 'as well as' and 'neither/nor' an additional

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