Agreement in Sentence Comprehension
5.4 Leftward Attraction out of a Relative Clause
5.4.1 Experiment 3
Experiment 3 was designed to test whether evidence for leftward attraction can be found in the given relative clause construction. To recapitulate, the term leftward attraction refers to attraction caused by a distractor disturbing the agreement rela-tion between a controller to its left and the corresponding agreement target to its right. The classical configuration for attraction with the distractor NP being part of a PP modifying the subject is an instance of leftward attraction. The parallelism of the two configurations is shown in (21).
(21) a. [NPThe coach[PPof theATHLETES ]]was suspended.
b. [NPThe coach[RCwhoseATHLETES were doped]]was suspended.
Besides the superficial similarity, there are at least three important differences between the two constructions. The first difference concerns the categorial status of the modifier. It is a clause in (21b) but only a phrase in (21a). The second difference is related to the clausal versus phrasal nature of the modifier. Crucially, the relative clause in (21b) involves a subject–verb agreement relation of its own whereas the PP in (21a) does not. As explained in the discussion of Experiment 2, the agreement relation in the relative clause could be vulnerable to attraction as well. In order to reduce the influence of agreement errors in the relative clause, Experiment 3 employs sentences with the distractor NP in object function. A relevant example illustrating the type of sentences investigated in Experiment 3 is shown in (22).
(22) Ich
‘I hope that the neighbor whose children I met has called.’
In (22), the NP der Nachbar (‘the neighbor’) is the agreement controller for the clause-final auxiliary hat (‘has’). The controller is modified by a relative clause containing the distractor Kinder (‘children’). Note that the subject of the relative clause is not the distractor, but rather the first-person pronoun ich. Since this pronoun controls agreement within the relative clause, rightward attraction into the relative clause affects all versions of (22) resulting from varying the number specifications of controller and distractor likewise. Therefore, rightward attraction would not have any visible effects here even if it occurred.
The main aim of Experiment 3 is to test whether the distractor Kinder, which intervenes between the controller Nachbar and the clause final auxiliary hat, leads to attraction errors. Furthermore, Experiment 3 examines sentences in which the number specifications on Nachbar and Kinder are reversed. In other words, Experiment 3 addresses the question whether leftward attraction occurs in the relative-clause construction under examination at all and if so, whether or not the resulting attraction pattern exhibits asymmetry between singular and plural attraction. Finding an asymmetry will argue that feature transfer during subject integration caused the errors; finding no asymmetry will argue that the distractor interfered during subject retrieval.
5.4.1.1 Method
Participants and Procedure
Sixty-four students from the University of Konstanz took part in this experiment.
The same procedure was used as in the previous experiments.
Materials
Forty sentence sets following the model in (22) were created. All sentences con-tained a matrix clause and a complement clause which in turn concon-tained a relative clause. The agreement relation addressed by the experiment is the agreement re-lation in the embedded complement clause. The controller was the subject of this embedded clause and modified by a relative clause immediately attached to it. This relative clause was introduced by a noun phrase consisting of a posses-sive relative pronoun (dessen/deren ‘whose’) and the distractor noun. The relative clause initial NP was always the direct object of the relative clause. The subject of
the relative clause was the first-person pronoun ich (‘I’). The relative clause verb was unambiguously marked for first person singular. The finite verb of the com-plement clause occurred in clause-final position and therefore after the relative clause.
Each sentence had eight versions according to the factors Controller, Distrac-tor and Grammaticality. The controller was either a singular or plural noun. The distractor matched or mismatched the controller in number. The factor Grammat-icality distinguished grammatical and ungrammatical sentences. The latter were derived by changing the number specification of the complement-clause verb. The relative clause was always grammatical. A sample sentence with all its grammat-ical versions is shown in Table 5.6.
Table 5.6: Sample Sentence Set of Experiment 3.
Singular Controller
Match Ich habe gehört, dass der Doktorand, dessen Professor ich in der I have heard that the PhD-student whose professor I in the Mensa getroffen habe, den Vortrag abgesagt hat.
cafeteria met have the talk canceled has
Mismatch Ich habe gehört, dass der Doktorand, dessen Professoren ich in der I have heard that the PhD-student whose professors I in the Mensa getroffen habe, den Vortrag abgesagt hat.
cafeteria met have the talk canceled has Plural Controller
Match Ich habe gehört, dass die Doktoranden, deren Professoren ich in der I have heard that the PhD-students whose professors I in the Mensa getroffen habe, den Vortrag abgesagt haben.
cafeteria met have the talk canceled have
Mismatch Ich habe gehört, dass die Doktoranden, deren Professor ich in der I have heard that the PhD-students whose professor I in the Mensa getroffen habe, den Vortrag abgesagt haben.
cafeteria met have the talk canceled have
‘I have heard that the PhD-student(s) whose professor(s) I met in the cafeteria has canceled the talk.’
Note. Ungrammatical sentences were derived by changing the final verb—a singular verb was replaced by a plural verb and vice versa.
The experimental stimuli were organized into eight counterbalanced lists as described for the two experiments before. Each participant saw just one list which was randomized for her or him individually. In addition to the experimental
sen-tences, filler items were included with a ratio of experimental sentences to filler sentences of about 1:4. The filler sentences covered a variety of grammatical and ungrammatical constructions. Most of them served as experimental stimuli in ac-companying but unrelated experiments.
5.4.1.2 Results Judgments
As before, correct responses were scored as 1 and incorrect ones as 0, to allow for applying a mixed logit model. The model includes participants and items as ran-dom effects and Grammaticality, Controller and Distractor as fixed effects. As vis-ible in Table 5.8, the model found significant main effects of Controller and Dis-tractor as well as a marginally significant main effect of Grammaticality. There are also significant interactions, all involving the factor Controller. In particular, the interaction involving all three factors is significant. Inspection of the percentages of correct judgments (Table 5.7) suggests that the interactions are mainly driven by one condition that deviates from the overall pattern: Ungrammatical sentences with a plural controller and a plural distractor received more judgments errors than expected. This drop is inter alia responsible for the marginally significant main ef-fect of Grammaticality. There is only one pair in which ungrammatical sentences received a higher error rate than corresponding grammatical sentences—sentences with a plural controller and a plural distractor. In this pair, there is an error rate difference of about 10 percentage points. In all others pairs, errors were equally common in grammatical sentences and ungrammatical counterparts.
Table 5.7: Percentages of Correct Judgments in Experiment 3
singular controller plural controller
Match Mismatch Match Mismatch Mean
grammatical 92 (1.5) 81 (2.2) 88 (1.8) 76 (2.4) 84
ungrammatical 94 (1.4) 79 (2.4) 77 (2.4) 74 (2.5) 81
Mean 93 80 82 75
Note. Values enclosed in parentheses represent standard errors.
Singular sentences received less judgment errors than plural sentences (mean accuracy: 86% correct vs. 79% correct). The plural penalty is visible in all pairs, but ungrammatical sentences with a plural controller and a plural distractor con-tribute once more in a special way. This time, they boost the overall effect. The in-crease in error rates is about 5 percentage points in all pairs, except in ungrammat-ical sentences in the match condition for which it is 17 percentage points (a drop
Table 5.8: Summary of Fixed Effects in the Mixed Logit Model for Judgments in Experi-ment 3 (Log-Likelihood=−1098)
Estimate SE z p
(Intercept) 1.824 .116 15.78 < .001 **
Grammaticality −0.219 .120 −1.82 .069 +
Controller −0.707 .120 −5.87 < .001 **
Distractor −0.927 .121 −7.69 < .001 **
Grammaticality×Controller −0.476 .241 −1.98 .048 *
Grammaticality×Distractor 0.157 .240 .65 .514
Controller×Distractor 0.779 .241 3.24 .001 **
Grammaticality×Controller×Distractor 1.025 .481 2.13 .033 * + p<.1, * p<.05, **p<.01
from 94% correct to only 77%). This drop—which the corresponding mismatch condition did not join—also blurred the effect of Distractor, i.e. the attraction ef-fect. For all pairs of match condition and corresponding mismatch condition, the difference in correctness is of comparable size, but in ungrammatical sentences with a plural controller, the effect is reduced to 5 percentage points. As a re-sult, we get the impression of an asymmetric attraction pattern in ungrammatical sentences (cf. Figure 5.2).
Attraction Rate
grammatical ungrammatical Error−rate difference 05101520
singular subject plural subject
Attraction Penalty
grammatical ungrammatical Response−time difference (ms) −100255075100
singular subject plural subject
Figure 5.2: Attraction rates and attraction penalties in Experiment 3
Judgment Times
Response times were corrected for outliers as described for the previous experi-ments. Table 5.9 shows the resulting response times for correct judgexperi-ments. Re-sponse times were analyzed using a linear mixed-effects model with participants and items included as random effects and Grammaticality, Controller and Distrac-tor as fixed effects. The model obtained only two significant main effects: an ef-fect of Grammaticality and an efef-fect of Controller (cf. Table 5.10). It took partic-ipants longer to reject an ungrammatical sentence (on average 748 ms) than to ac-cept a grammatical sentence (640 ms). Judgment times for plural sentences were reliably longer than for sentences with a singular controller (722 ms vs. 667 ms).
The increase was more pronounced in ungrammatical sentences; the interaction of Controller and Grammaticality marginally significance. The model also shows that the factor Distractor had no effect, as a main effect as well as in interaction with other factors. In each pair of match condition and corresponding mismatch condition, response times are virtually identical (see also right panel of Figure 5.2).
Table 5.9: Mean Response Times for Correct Judgments (in ms) in Experiment 3 singular controller plural controller
Match Mismatch Match Mismatch Mean
grammatical 613 (19) 632 (22) 659 (20) 660 (23) 640
ungrammatical 715 (19) 708 (21) 792 (22) 788 (23) 748
Mean 664 669 721 723
Note. Values enclosed in parentheses represent standard errors.
5.4.1.3 Discussion
The most important result of Experiment 3 is the substantial number of judgment errors when controller and distractor differ in number. Before accepting this effect as an indication of leftward attraction out of a relative clause we have to consider an alternative explanation. The mismatch conditions might be more difficult to process because they require additional effort to determine the relation between possessor and possessee. There are two reasons why I think that this is not an appropriate explanation for the effect: Processing difficulties of this sort should be evident in response times but in fact no mismatch penalty is observed in response times. Furthermore, the determination of the possessor–possessee relation should be particularly difficult in plural sentences which in principle allow a distributive
Table 5.10: Summary of Fixed Effects in the Linear Mixed-Effect Model for Response Times in Experiment 3 (Log-Likelihood=−14998)
Estimate SE t pMCMC
(Intercept) 700.90 25.34 27.66 < .001 **
Grammaticality 106.30 12.53 8.48 < .001 **
Controller 52.49 12.56 4.18 < .001 **
Distractor 5.96 12.52 0.48 .637
Grammaticality×Controller 43.29 25.03 1.73 .087 +
Grammaticality×Distractor −19.80 25.02 −.79 .435
Controller×Distractor −13.84 25.07 −.55 .586
Grammaticality×Controller×Distractor 12.44 50.06 .25 .805 Note. Only response times for correct responses entered analyses.
+ p<.1, * p<.05, **p<.01
reading. The increase of error rates in the mismatch conditions, however, was similar in singular and plural sentences—at least in grammatical sentences; for ungrammatical sentences the issue of an asymmetry is less clear because of the unexpected drop in accuracy in ungrammatical sentences with a plural controller and a plural distractor. Taken together, I conclude that the judgment errors resulted indeed from attraction.
As pointed out in the introduction of the chapter and the discussion of Exper-iment 2, most previous studies found only little attraction or no attraction when the distractor was part of a relative clause modifying the subject (cf. Bock and Cutting, 1992; Bock and Miller, 1991; Nicol, 1995; Nicol et al., 1997; Kail and Bassano, 1997, but see Solomon and Pearlmutter, 2004. There are three properties of Experiment 3 which may account for the discrepancy. Experiment 3 investi-gates language comprehension whereas most studies cited above address language production. Language comprehension, on the other hand, has been shown to be vulnerable to leftward attraction caused by a distractor located in a relative clause (Nicol et al., 1997). While Nicol (1995) found only spurious signs of attrac-tion from a relative clause in language producattrac-tion, Nicol et al. (1997), using the same material, found an attraction effect in sentence comprehension. Neverthe-less, comprehension seems to be similar to production insofar as a distractor in-side a PP is to be more effective than a distractor inin-side a relative clause (Kail and Bassano, 1997). The second difference between the present experiment and previ-ous studies concerns the language of the experiments. Experiment 3 tests German whereas the cited studies employ English sentences. To the best of my knowledge, attraction out of a relative clause has been examined so far only in English. For all other languages, corresponding studies are lacking. Though the current study
aims to close this gap the investigation of language specific differences must be left to future research. The third and probably most important difference concerns the syntactic and semantic connection of controller and distractor. While the two were not syntactically linked in previous studies, controller and distractor were linked via a possessive relative pronoun in Experiment 3. The possessive relation entails also a close semantic link. Solomon and Pearlmutter (2004) report that close semantic association boosts the incidence of attraction. I conclude that the close syntactic and semantic connection enables the distractor to interfere in the agreement processes involving the controller more effectively than in sentences in which controller and distractor are linked less tightly.
In Experiment 3, attraction errors of equal magnitude occurred for singular and plural controllers, at least in grammatical sentences. The reduced attraction rate found in ungrammatical sentences with a plural subject probably results from the increase of judgment errors in the match condition as discussed above. The absence of an asymmetry contrasts with the strict asymmetry usually found. Al-though there seems to be both cross-linguistic and intra-linguistic variance, studies investigating German sentence production consistently report that attraction is re-stricted to singular distractors when the latter was part of a complex subject NP.
For modifier attraction in sentence comprehension, there are conflicting results.
While Hölscher and Hemforth (2000) report a strict but reversed asymmetry, Ex-periment 1 demonstrated the standard asymmetry for grammatical sentences and no asymmetry for ungrammatical sentences (cf. section 4.3.5 in chapter 4). There is another exception to the standard asymmetric pattern in German and this excep-tion concerns object attracexcep-tion (Hemforth and Konieczny, 2003; Konieczny et al., 2004). Apparently, the emergence of an asymmetry depends on the particular construction in which attraction occurs. I suspect that the mechanism underlying an attraction error may differ from construction to construction. The attraction pattern in Experiment 3 is difficult to reconcile with a feature transfer mechanism, at least under the assumption of an asymmetric representation of number. An al-ternative that can handle the occurrence of attraction errors in singular sentences and plural sentences is to assume that attraction results from retrieval errors in the course of agreement checking. Prima facie it is not obvious whether a retrieval-interference account would predict an asymmetry. As explained in section 4.4.3 of chapter 4, number is probably not among subject-retrieval cues during first-pass parsing. Under this perspective, singular and plural distractors are equally likely to be erroneously retrieved; no asymmetry would result. Thus, the attraction pattern found in Experiment 3 is compatible with a retrieval-interference account. Since attraction errors occurred in both grammatical and ungrammatical sentences, Ex-periment 3 provides supporting evidence for the Checking Hypothesis and sheds doubt on the Reanalysis Account proposed in Wagers et al. (2009).
The attraction effect described above was not visible in judgment times. This
finding is compatible with both a feature transfer account and the checking ac-counts. In both cases, attraction will only be visible in judgment times if errors are revised in a sufficient number of instances. Reanalysis triggered by a real or an apparent agreement violation would result in longer response times. Grammatical sentences which are seemingly ungrammatical because of attraction are expected to receive longer response times in comparison to grammatical sentences in the match condition. Although judgment times numerically show this pattern, the dif-ference is not significant. The absence of a reliable attraction penalty suggests that no or only few attraction-related revisions took place in Experiment 3. Consider next ungrammatical sentences. In this sentence type, attraction does not lead to an illusionary agreement violation but rather hides a real one. Since attraction results in seeming agreement, the parser has no trigger to revise its error. Ungrammatical sentences are therefore supposed to show no signs of a reanalysis-based attraction penalty. If reanalysis occurs at all, faster response times in the mismatch condi-tions are expected. Reanalysis should occur more often in the match condition and thus enhance response times in this condition. This expectation is not confirmed by the data obtained in Experiment 3 though, numerically, a spurious trend in the expected direction is visible. The absence of hints for reanalysis is in a line with prior research showing that agreement violations often lead to an immediate re-jection of the corresponding sentence and that reanalysis is performed only from time to time (Bader and Meng, 1999; Meng and Bader, 2000a). Notice, further-more, that the chances to detect signs of reanalysis in the context of attraction are small. Given that only a small proportion of sentences shows attraction effects and supposed that reanalysis is initiated only in a fraction of these instances, ef-fects of reanalysis are hardly detectable by means of response times in a judgment task. For this reason, I hesitate to interpret the absence of an attraction penalty in response times as evidence against the reanalysis account. Furthermore, it is not obvious whether the reanalysis account predicts an attraction penalty in judgment times at all.
In addition to attraction, Experiment 3 replicates the plural effect found in Ex-periment 2: participants produced more judgment errors and needed more time for a correct judgment when the subject was a plural NP. The plural penalty was more pronounced in ungrammatical sentences. As discussed for Experiment 2, the plural penalty can be explained either in terms of decay or in terms of semantic complexity. Experiment 3, however, offers no way to differentiate the two hy-potheses; yet, the difference between grammatical and ungrammatical sentences points towards the decay hypothesis. I will come back to the plural effect in sec-tion 5.6.4.