{ "paper_id": "P81-1019", "header": { "generated_with": "S2ORC 1.0.0", "date_generated": "2023-01-19T09:15:00.255144Z" }, "title": "SEARCH AND INFERENCE STRATEGIES IN PRONOUN RESOLUTION : AN E~ERIMENTAL STUDY", "authors": [ { "first": "Kate", "middle": [], "last": "Ehrlich", "suffix": "", "affiliation": {}, "email": "" } ], "year": "", "venue": null, "identifiers": {}, "abstract": "The qusstlun of how people resolve pronouns has the various factors combine.", "pdf_parse": { "paper_id": "P81-1019", "_pdf_hash": "", "abstract": [ { "text": "The qusstlun of how people resolve pronouns has the various factors combine.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "Abstract", "sec_num": null } ], "body_text": [ { "text": "been of interest to language theorists for a long time because so much of what goes on when people find referents for pronouns seems to lie at the heart of comprehension. However, despite the relevance of pronouns for comprehension and language cheorT, the processes chat contribute to pronoun resolution have proved notoriously difficult Co pin down.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "Part of the difficulty arises from the wide range of fac=ors that can affect which antecedent noun phrase in a tex~ is usderstood to be co-referentlal with a particular pronoun. These factors can range from simple number/gender agreement through selectional rescrlc~ions co quite complex \"knowledge chat has been acquired from the CaxC (see Webber, (1978) for a neatly illustrated description of many of these factors). Research in psychology, artificial intelligence a~d linguistics has gone a long way toward identifying some of these factors and their role in pronoun resolu~ion.", "cite_spans": [ { "start": 341, "end": 355, "text": "Webber, (1978)", "ref_id": "BIBREF8" } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "For instance, in psychology, research carried ouC by Caramazza =-d his colleagues (Caramazza et el, 1977) as well as research chat I have dune (Ehrllch, 1980) , has demuns~rated that number/sender agreement really c=-fumcciun to constrain the choice of referent in a way Chat signiflcantly facilltaCes processing. Within an AI framework, there has been some very interesting work carried out by Sidner (1977) m~d Grosz (1977) thac seeks to identify the current topic of a Cex1: and co show Chat knowledge of the topic can considerably sillily pronoun resolutlon.", "cite_spans": [ { "start": 82, "end": 105, "text": "(Caramazza et el, 1977)", "ref_id": null }, { "start": 143, "end": 158, "text": "(Ehrllch, 1980)", "ref_id": null }, { "start": 395, "end": 408, "text": "Sidner (1977)", "ref_id": "BIBREF6" }, { "start": 413, "end": 425, "text": "Grosz (1977)", "ref_id": "BIBREF3" } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "It is important that people are able co select appropriate referents for pronouns and co have some basis for that decision. The research discussed so far has mentioned some of the factors Chac contribute co chose decisiuns. However, part of ~he problem of really understanding how people resolve pronouns is knowing how Certainly it is important a~d useful to polnc to a particular factor as concributlng to a reference decision, but in many texts more than one of these factors will be available to a reader or listener. One problem for the theorist is then to explaln which factor predominates in the decision as well as to describe the scheduling of evaluaclon procedures. If it could be shown that there was a stricc ordering in which tests were applied, say, number/gender agreement followed by selectionai restrictions followed by inference procedures, pronoun resoluclon may be simp- These two types of strategy, which will be referred to msem\u00a2-lically as inference and search strategies, have different kinds of characteristics. A search strategy dictates the order in which candldaces are evaluated, but has no machinery for carrying out the evaluation.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "The inference strategy helps to set up the representaclon of the information in the cexC agains c which candldacas can be evaluated, but has ~o way of finding the c~aldidates. ~n the rest of this paper, she way these straCegles ~ighc interact will be explored and the results of two studies will be reported that bear on the issues.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "One possible search strategy is ~o examine candidates serially beginning with the one menKioned most recently and working back through the text. This strategy makes some sense because, as Hobbs (1978) has pointed out, most pronouns co-refer with antecedents Chat were menr.laned within the last few senuences.", "cite_spans": [ { "start": 188, "end": 200, "text": "Hobbs (1978)", "ref_id": "BIBREF4" } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "Thus, a serial search s~rategy provides a principled way of rescric~Lng how a text is searched. Moreover, there is some evidence fro~ psychological research ~hat it takes longer to resolve pronouns when the antecedent wlch which the pronotn~ co-refers is far rather than near the pronoun (e.g. Clark & $engul, 1979; SprlnEston, 1975 (2) John sold a car to Fred because he needed it a series of inferences based in part an out knowledge of selling a~d needing, supports ~he selection of Fred rather ~h=m John as referent for the pronoun \"he\". In the experiments to be reported, it was 'lexical'", "cite_spans": [ { "start": 294, "end": 315, "text": "Clark & $engul, 1979;", "ref_id": null }, { "start": 316, "end": 332, "text": "SprlnEston, 1975", "ref_id": null } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "inferences ra~her ~han the oCher kind that were manipulated.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "Subjects in ~he experiment were asked to read texts such as the a~e given below:", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "( In either case the inference will be drawn in response to r/Re need to decide on the acceptability of the candidate. In the second model, the inference is triggered by the anaphoric expression, e.g. \"in his room\" An the third sentence, and the need to relate chat expression to the location \"inside\" mentioned in a previous sentence. The inference is expected to take a certain amotmt of time to be drawn (cf. Kintsch, 1974) .", "cite_spans": [ { "start": 412, "end": 426, "text": "Kintsch, 1974)", "ref_id": "BIBREF5" } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "According to the second model, one would expect that in cases where the antecedent is near the pronoun, there will be some effect due to inference because the process may not be completed in time to answer the question. When the antecedent is far from the pronoun, however, the inference process will be completed and hence no effect of inference should still be detected. Webber, 1978) .", "cite_spans": [ { "start": 373, "end": 386, "text": "Webber, 1978)", "ref_id": "BIBREF8" } ], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "The picture of pronoun resolution that emerges from the studies reported here, is one in which effects of distance between the pronoun and its antecedent may play some role, not as a predicator of pronominal reference as has often been ~houEht, but as part of a search strateEy. There certainly are cases where nearer antecedents seem to be preferred over ones further back in the text; however, it is more profitable to look ~o concepts such as foregroundin E (of. Chafe, 1974) rather than silnple recency for explanations of the preference.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null }, { "text": "\u2022 It is also of some interest to have shown that inferences ~my con~rlbute ~o pronoun resolution huc drawn for other reasons.", "cite_spans": [], "ref_spans": [], "eq_spans": [], "section": "", "sec_num": null } ], "back_matter": [], "bib_entries": { "BIBREF0": { "ref_id": "b0", "title": "Comprehension of anaphoric pronom~s", "authors": [ { "first": "A", "middle": [], "last": "Carama~za", "suffix": "" }, { "first": "E", "middle": [], "last": "Grober", "suffix": "" }, { "first": "C", "middle": [], "last": "Garvey", "suffix": "" }, { "first": "J", "middle": [], "last": "Yates", "suffix": "" } ], "year": 1974, "venue": "Journal of Verbal Learning and Verbal Behavior", "volume": "6", "issue": "", "pages": "111--133", "other_ids": {}, "num": null, "urls": [], "raw_text": "Carama~za, A., Grober, E., Garvey, C. and Yates, J. (1977). Comprehension of anaphoric pronom~s. Journal of Verbal Learning and Verbal Behavior, i_6, 601-9. ~fe, W.L. (1974). Language and consciousness. Lan__- guage, 50, 111-133.", "links": null }, "BIBREF1": { "ref_id": "b1", "title": "search of referents for nouns and pronouns. ~.emory and Cog-hi=ion", "authors": [ { "first": "H", "middle": [ "H" ], "last": "Clark", "suffix": "" }, { "first": "C", "middle": [ "J" ], "last": "Sengul", "suffix": "" } ], "year": 1979, "venue": "", "volume": "7", "issue": "", "pages": "35--41", "other_ids": {}, "num": null, "urls": [], "raw_text": "Clark, H.H., and Sengul, C.J. (1979). In search of re- ferents for nouns and pronouns. ~.emory and Cog- hi=ion, 7, 35-41.", "links": null }, "BIBREF2": { "ref_id": "b2", "title": "Interpreclng ana-92 photic relations: =he integration cf semantic information while reading", "authors": [ { "first": "K", "middle": [], "last": "Ehrlich", "suffix": "" }, { "first": "S", "middle": [], "last": "; -Garrod", "suffix": "" }, { "first": "A", "middle": [ "J" ], "last": "Sanford", "suffix": "" } ], "year": 1977, "venue": "Journal of Verbal Learnin~ and Verbal Behavior", "volume": "32", "issue": "", "pages": "77--90", "other_ids": {}, "num": null, "urls": [], "raw_text": "Ehrlich, K. (1980). Comprehension of pronouns. Ouar- terlv Journal of Exper~nental PsTcholo~, 32, 247- Garrod, S. and Sanford,A.J. (1977). Interpreclng ana- 92 photic relations: =he integration cf semantic information while reading. Journal of Verbal Learnin~ and Verbal Behavior, 16, 77-90.", "links": null }, "BIBREF3": { "ref_id": "b3", "title": "The representation and use of focus in a system for understanding dialogs", "authors": [ { "first": "B", "middle": [ "J" ], "last": "Grosz", "suffix": "" } ], "year": 1977, "venue": "Proceedin~ of =he Fifth International Joint Conference on Artificial Intelligence", "volume": "", "issue": "", "pages": "", "other_ids": {}, "num": null, "urls": [], "raw_text": "Grosz, B.J. (1977). The representation and use of focus in a system for understanding dialogs. In Proceedin~ of =he Fifth International Joint Con- ference on Artificial Intelligence. Cambridge: MIT.", "links": null }, "BIBREF4": { "ref_id": "b4", "title": "Resolving pronoun references", "authors": [ { "first": "J", "middle": [ "R" ], "last": "Hobbs", "suffix": "" } ], "year": 1978, "venue": "Lingua", "volume": "44", "issue": "", "pages": "311--338", "other_ids": {}, "num": null, "urls": [], "raw_text": "Hobbs, J.R. (1978). Resolving pronoun references. Lingua, 44, 311-338.", "links": null }, "BIBREF5": { "ref_id": "b5", "title": "The representation of meaning in memory", "authors": [ { "first": "W", "middle": [], "last": "Kintsch", "suffix": "" } ], "year": 1974, "venue": "", "volume": "", "issue": "", "pages": "", "other_ids": {}, "num": null, "urls": [], "raw_text": "Kintsch, W. (1974). The representation of meaning in memory. Potomac, Md: Erlbatnn.", "links": null }, "BIBREF6": { "ref_id": "b6", "title": "Levels of ccmplexlty in discourse for anaphora disambiguatlon and speech act interpretation", "authors": [ { "first": "C", "middle": [], "last": "Sidner", "suffix": "" } ], "year": 1977, "venue": "Proceedings of =he Fifth International Joint Conference cn Artificial Intel-li~ence. Cambridge: ~flT", "volume": "", "issue": "", "pages": "", "other_ids": {}, "num": null, "urls": [], "raw_text": "Sidner, C. (1977). Levels of ccmplexlty in discourse for anaphora disambiguatlon and speech act inter- pretation. In Proceedings of =he Fifth Inter- national Joint Conference cn Artificial Intel- li~ence. Cambridge: ~flT.", "links": null }, "BIBREF7": { "ref_id": "b7", "title": "Some cognitive aspects of presupposed coreferential anaphora. Unpublished doctoral dissertation", "authors": [ { "first": "F", "middle": [ "J" ], "last": "Springsron", "suffix": "" } ], "year": 1975, "venue": "", "volume": "", "issue": "", "pages": "", "other_ids": {}, "num": null, "urls": [], "raw_text": "Springsron, F.J. (1975). Some cognitive aspects of presupposed coreferential anaphora. Unpublished doctoral dissertation, Stanford University.", "links": null }, "BIBREF8": { "ref_id": "b8", "title": "Bolt, Beranek and Newman, Inc. TABLE I Percent correct responses (?.C.) and mean response =~mes", "authors": [ { "first": "B", "middle": [ "L" ], "last": "Webber", "suffix": "" } ], "year": 1978, "venue": "", "volume": "", "issue": "", "pages": "", "other_ids": {}, "num": null, "urls": [], "raw_text": "Webber, B.L. (1978). A formal approach to discourse anaphora. 8BN report no. 3761. Cambridge, Mass: Bolt, Beranek and Newman, Inc. TABLE I Percent correct responses (?.C.) and mean response =~mes (R.T.).", "links": null } }, "ref_entries": { "FIGREF0": { "uris": null, "text": "3) Fred was outside all day John was inside all day a) He had a sleep inside after lunch b) He had a sleep in his room after lunch and then immedla~ely after, answer a question such as '~dho had a sleep after lunchY\" Chat was designed to elicit the referent of the pranou~ in ~he las~ sentence. Two factors were independently varied. The antecedent could be near or far from the pronoun, ~he lacier affected by switching the order of the first \u00a3wo sen-~ences. The second factor was whether a 'bridg~Ing' inference had to be drw~n ~o es~chllsh co-reference bed, sen part of the predlca~e of the lasc sentence and ~he target sentence. The ~o versions, (a) no inference and (b) inference, are shown as alternative ~hird sencanoes in example (3) -hove. The principal measures were ~he Lime to answer ~he question and ~he accuracy of ~he respunse. The experi-~ent addresses ~wo critical issues. One is whether ~he 'lewical' inference is drEdn as part of the evaluaLion procedure, or, whether it is drawn independently of Cha~ process. The o~her issue concerns the search sura~eEy itself: do subjects examine can-dlda~es serially, and, if so, do they s~ill use oCher criteria to reject the first canal/dace and choose the second? Two dlstincc models of processing can be con-s~rucced from a conslderarion of Chess issues. In the case where inferences are triggered by the need ~o 9O evaluate a candidate, any effect due to extra processing should be unaffected by whether the antecedent ks near or far from the pronoun.", "num": null, "type_str": "figure" }, "TABREF2": { "num": null, "type_str": "table", "content": "
observation raises some in~eresclng questions con-in response to a question ellci~Ing ~he referent, ~he
ence supports the resul~s of earlier studies, par-
cerning wha~ triggers an inference to be drawn. Onei,~llcarAon
tlcularly those of Garrod and Sanford (1977).Whac the
answer, supplied by Garrod & Sanford in ~heir experi-
present study fails to do, however, is to determine
ment.s, is thac a relation baleene~cpressioas muse
whether that inference ks drawn spontaneously, while
someh~ be perceived before an inference is drawn to
reading.Previous research (e.g., ~intsch, 1974, Garrod
de~e~-mlne ~e nature of ~he relation. I~n o~her words,
ald Sanford, 1977) has shown ~hat inferences are more
people do not draw inferences randomly to relate lln-
likely to be drawn while reading ~han at a response
8uisuic expressions. Thus, whereas Garrod & $anford
stage.It was thus of some interest to know when ~he
found ~ha~ subjects would infer co-reference between
lexical inferences in ~he present study were drawn.
\"bus\" and \"vehicle\" in exa~le (i), they failed to make
This issue was examined by modifying the previous ex-
that connection, qui~ rightly, in a slnuLlar passage
periment to include both an additional measure of read-
shown below:
ing time and a 1.5s delay between presentation and test.
(5)A bus came roaring round the corner
The latter modification is important since if subjects
It nearly smashed some vehicles
are drawing inferences while reading, ~he process may
What kinds of strategies do readers adop~ when
not be completed by the time the question is asked
they search ~heir memory to find plausible referents
i~mnedlately after presentation.The introduction of a
for pronouns? Resul~s of che experiments reported here
delay also allows for a further test of the two pro-
point ~o a strategy in which an~ities are examined
The two models assume rationality onceasing modeled outlined earlier.If indeed 'lexlcal'
serially from ~he pronoun. The purpose of a serial
the part of the subjects;that is, they assume thatinferences are drawn to establish co-reference between
search strategy is to provide a principled we7 in which
subjects will accurately select the further antecedentanaphoric expressions rather than to determine pro-
readers can ex\"rn'Ine ~ho~e entities they have stored in
where appropriate even though recency would predictnominal reference, as the previous experiment indicated,
mmory, for ~heir appropriateness as ~he referent of a
selecr.lon of the first candidate that is evaluated.Ifthen there should be an effect of inference on reading
particular prono ~-~. The strategy is ~hus unnecessary
this assumption ks valid, subjects should select the~ime but not at response when there is a delay, because
when there is only one emr/~y in memory by vlr~ue of
far antecedent where appropriatemere often than theby response ~he inference should have been dr~m.The
sim~le criteria such as humor and gender agreement
(erroneous) near candidate.data were consistent with this hypothesis.However,
The results of the experiment, shown An Table 1, wi~h ~he pronoun. What cons~.Itutes 'simple' criteriawhat also emerged from the second study was that only
support the second model; ' lexlcal' inferences are is, of course, an open question; che answer, however,some of ~he passages seemed to elicit inferences at
drawn only once and in response to an anaphoric expres-will materially affect ~he applicability of ~he searchreading; the number of passages was increased in the
sion. The data also provide evidence of a serial search s~rategy.second experiment ro corn%tar possible repetition
strategy by showing that there are more errors and The ~t important part of reference resolution is,effects.In fact, for half the passages subjects res-
longer latencles associated with far rather than near however, deciding on the referent. A serial searchponded by saying there was no answer.An example of
antecedents. strategy has no machinery for evaluating candidates, i~ The data further show that even when thesuch a passage is given below:
correct choice is far from the pronoun, subjects will can only direct ~he order in which candidates are(4)Jill had a newspaper in the living-room
choose it in preference to ~he nearer condidate, thus examined. The process of selecting a plausible referentAnn had a book in the living-room
demonstrating that a serial search strategy alone can-depends on ~he inferences a reader has drawn while ~heShe read some chemistry An the evening
not predict the choice of referent. ~ext is read. Thus, when subjects found i~ hard ~oIt was also the case for these passages that the in-
The inferences that subjects had to draw in this selec~ a referent at all ~hey also failed to draw m~myferences did not seem to be drawn while reading but
experiment concerned simple lexlcal relations. inferences while ~hey read ~he ~ext. Moreover, because Therather in response to the question.There is some
increase in latency due to having drawn such an infer-~he inferences for ~hese passa8es did seem to be drawndoubt here about cause and effect, nevertheless, the
", "html": null, "text": "is that inferences for che clearer material are generally drawn spontaneously and before a specific need for ~he informar.lon arises. One can conjecture from ~hese data that the select_ion of plausible refer-an~s is dependent on how well a reader has understood ~he preceding text. If inferences are not drawn on~il a specific need arises, such as finding a referent, ~hen it may be too late, to selec~ a referent easily or accurately, l~us, reference can also be viewed in terms of what a ~ext makes available for anaphoric reference (cf." } } } }