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Processing VP-ellipsis and VPanaphora with structurally parallel
and nonparallel antecedents: An eyetracking study
a
b
Leah Roberts , Ayumi Matsuo & Nigel Duffield
b
a
Max Planck Institute for Psycholinguistics, Nijmegen,
Netherlands
b
Centre for Linguistic Research, University of Sheffield,
Sheffield, UK
Version of record first published: 06 Sep 2012.
To cite this article: Leah Roberts, Ayumi Matsuo & Nigel Duffield (2012): Processing VP-ellipsis
and VP-anaphora with structurally parallel and nonparallel antecedents: An eye-tracking study,
Language and Cognitive Processes, DOI:10.1080/01690965.2012.676190
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LANGUAGE AND COGNITIVE PROCESSES, 2012, iFirst, 119
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Processing VP-ellipsis and VP-anaphora with
structurally parallel and nonparallel antecedents:
An eye-tracking study
Leah Roberts1, Ayumi Matsuo2, and Nigel Duffield2
1
2
Max Planck Institute for Psycholinguistics, Nijmegen, Netherlands
Centre for Linguistic Research, University of Sheffield, Sheffield, UK
In this paper, we report on an eye-tracking study investigating the processing of
English VP-ellipsis (John took the rubbish out. Fred did [] too) (VPE) and VPanaphora (John took the rubbish out. Fred did it too) (VPA) constructions, with
syntactically parallel versus nonparallel antecedent clauses (e.g., The rubbish was
taken out by John. Fred did [] too/Fred did it too). The results show first that VPE
involves greater processing costs than VPA overall. Second, although the structural
nonparallelism of the antecedent clause elicited a processing cost for both anaphor
types, there was a difference in the timing and the strength of this parallelism effect:
it was earlier and more fleeting for VPA, as evidenced by regression path times,
whereas the effect occurred later with VPE completions, showing up in second and
total fixation times measures, and continuing on into the reading of the adjacent
text. Taking the observed differences between the processing of the two anaphor
types together with other research findings in the literature, we argue that our data
support the idea that in the case of VPE, the VP from the antecedent clause
necessitates more computation at the elision site before it is linked to its antecedent
than is the case for VPA.
Keywords: Sentence processing; VP-ellipsis; Eye tracking during reading.
In order to interpret ellipsis clauses [(1) below], a link must be established between
the anaphoric element and the prior context. In this study, we investigate the
processing of anaphoric constructions in cases where the antecedent clause is either
structurally parallel in terms of its surface representation, as in (1a, c) or not, as in
(1b, d).1 Specifically, we address the question of whether different anaphor types,
Correspondence should be addressed to Leah Roberts, Centre for Language Learning Research,
Department of Education, University of York, Heslington, YO10 5DD, UK. E-mail: [email protected]
1
In recent theoretical work, for example, Merchant (2007, 2008), Tanaka (2011), it has been argued that
one of the ‘‘nonparallel’’ constructions investigated in this paper, namely, the passive (voice mismatch)
condition illustrated in (1), is in fact underlyingly syntactically parallel, and that apparent parallelism effects
found in traditional judgment data are best accounted for in terms of discourse factors (Kehler, 2000, 2002).
While acknowledging the relevance of such work in the overall treatment of VP-ellipsis, it does not, we
believe, invalidate any of the findings of the current paper. There are three reasons for this. First, it is unclear
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http://dx.doi.org/10.1080/01690965.2012.676190
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2
ROBERTS, MATSUO, DUFFIELD
VP-ellipsis (John didn’t want to []) (VPE) and VP-anaphora (John didn’t want to do it)
(VPA) are processed differently in real-time comprehension.
In linguistic theory, claims of a fundamental grammatical contrast between VPE
and VPA were first presented in Hankamer and Sag (1976) and Sag and Hankamer
(1984).2 These authors describe the formal differences between the two anaphor types,
and propose that there may be two separate processing mechanisms for interpreting
anaphoric elements: VPE (SURFACE ANAPHORA), involving a syntactic mechanism
such as copying (see also Frazier & Clifton, 2000, 2001), and the second, VPA, or
DEEP ANAPHORA, making reference to discourse representation. VPE and VPA,
illustrated in (1) and (2) below, are presented as the paradigm examples of this
SurfaceDeep split. (Note that these examples also illustrate a presumed contrast in
the effects of syntactic parallelism on the two constructions, a matter to which we
return directly.)
(1)
a. Someone had to put out the garbage, but John didn’t want to.
b. ??The garbage had to be put out, but John didn’t want to. [passive]3
c. John wanted someone to kiss him, but Jo didn’t want to.
d. ?*John wanted a kiss, but Jo didn’t want to. [nominal]
(2) a. Someone had to put out the garbage, but John didn’t want to do it.
b. The garbage had to be put out, but John didn’t want to do it. [passive]
c. John wanted someone to kiss him, but Jo didn’t want to do it.
d. John wanted a kiss, but Jo didn’t want to do it [nominal].
One of the major differences between the two anaphor types as discussed by Sag and
Hankamer is the ANTECEDENT REQUIREMENT: Surface Anaphors always require a
linguistic antecedent, even where the interpretation of the ellipsis clause is entirely
recoverable from the nonlinguistic context. This is shown in (3) (excepted from Sag &
Hankamer, 1984, p. 326):
to us that the intuitive judgments on which Merchant, Tanaka and others rely have any necessary primacy
over the experimental data presented here, which demonstrate a clear behavioural interaction between
(surface) parallelism and anaphor type, irrespective of any putative underlying grammaticality: that is to
say, surface mismatch implicitly ‘‘matters’’ to readers. Second, we have demonstrated in previous work,
using different measures, that antecedents containing voice mismatches are consistently judged less
acceptable than surface parallel antecedents with VPE, notwithstanding the fact that this parallelism effect
is weaker than with nominal antecedents (Duffield, Matsuo, & Roberts, 2009). Finally, the goals of this
paper are primarily psycholinguistic, rather than theoretical, in nature: we are concerned with how readers
process different surface strings in real time given varying contexts, rather than with how far behavioural
judgments comport with theoretical constructs. Of course, the two concerns should be ultimately related,
but such considerations are beyond the scope of this paper.
2
Those papers built on earlier discussion by Postal, Bresnan, Ross, and others, concerning the question
of whether ellipsis and (overt) pronominal anaphora should be handled by separate mechanisms*and
related to this*the issue of whether overt pronouns were the surface realization of underlying full nounphrases. Though the latter question appears to have been laid to rest by the late 1970s, the former question is
still a matter of some controversy.
3
Merchant (2007, 2008) discusses the fact that voice-mismatched pseudogapping (e.g., *Roses were
brought by some, and others did lilies) is worse than voice-mismatching VPE (e.g., This problem was to have
been looked into, but nobody did). The difference is assumed to lie in the size of the elided clause, with VPE
targeting sister of Voice, and thus low enough in the syntactic tree to be neutral between active and passive
voice, in contrast to pseudogapping (also sluicing and fragment answers), which involves the elision of a
constituent higher up in the tree (TP).
PROCESSING VP-ELLIPSIS AND VP-ANAPHORA CLAUSES
3
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(3)
[Hankamer points gun offstage, and fires, whereupon a blood-curdling female
scream is heard]
Sag: a. *I wonder who Ø. [sluicing, surface]
b. *I wonder who was Ø. [VPE, surface]
c. I wonder who she was. [definite pronominalization deep]
d. *Jorge, you shouldn’t have Ø. [VPE, surface]
e. Jorge, you shouldn’t have done it. [VPA, deep]
In these examples, the nonlinguistic event of seeing someone fire a gun followed by a
scream constitutes a sufficient antecedent context for interpretation in the anaphoric
cases in (c) and (e), but not for the sentences involving ellipsis (a, b, d). Conversely, the
examples in (4) and (5)*drawn once again from Hankamer and Sag’s original paper*
show that VPE structures provide a required (covert) antecedent for the following
pronoun it, whereas VPA structures do not (see also Bresnan, 1971; Grinder & Postal,
1971).
(4)
a. I’ve never ridden a camel, but Ivan has (ridden a cameli), and he says iti stank
horribly. [cf. 6b]
b. *I’ve never ridden a cameli, and iti stank horribly. (HS: 403404).
(5) a. *Jack didn’t cut Betty with a knife*Bill did it, and it was rusty [it the knife]
(Bresnan, 1971). [cf. 7b]
b. Jack didn’t cut Betty with a knife*Bill did, and it was rusty [it the knife]. (HS:
405406).
Murphy (1985) investigated readers’ on-line processing of VPE and VPA constructions (6) with long (a) and short (b) antecedents, testing empirically the idea that the
two constructions should be processed differently (cf. Hankamer and Sag’s account).
(6)
a. Jimmy swept the tile floor behind the chairs free of hair and cigarettes. Later his
uncle did too/Later his uncle did it too.
b. Jimmy swept the tile floor. Later his uncle did too/Later his uncle did it.
Murphy proposed that if a copying mechanism is in operation for VPE but not for
VPA, this predicts that the processing of the two anaphor types should be
differentially affected by the length of the antecedent clause. Specifically, given that
more linguistic material needs to be copied at the elision site, and no such copying
operation is assumed to take place for VPA interpretation, VPE should be more
strongly affected by long antecedent clauses (6a). Furthermore, greater distance
between the elision site and the antecedent should also cause more processing cost for
VPE than VPA since surface information has been found to decay more rapidly than
information derived from the discourse context (e.g., Johnson-Laird & Stevenson,
1970).
Murphy found that there was no difference observed in the processing of the two
anaphor types: rather, it was the length of the antecedent that affected reading times,
with longer antecedents causing greater processing costs for both VPE and VPA
constructions and this was only the case when the antecedents were close. He therefore
argued that these data suggest that with local antecedents, a copying mechanism is
employed in the interpretation of both VPE and VPA, whereas for distant antecedents,
interpretation takes place via reference to the discourse model, contrary to the
predictions of the Sag and Hankamer account.
4
ROBERTS, MATSUO, DUFFIELD
As well as testing distance and length effects, Murphy (1985, experiment 3) also
manipulated the ‘‘consistency’’ of the antecedent clause such that it was either
syntactically parallel (7a) or nonparallel (7b).
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(7)
a. Leslie kicked the ball, but Frank wouldn’t (wouldn’t do it).
b. The ball was kicked by Leslie, but Frank wouldn’t (wouldn’t do it).
This parallelism effect is discussed by Sag and Hankamer (1984) as reflecting another
formal difference between surface and deep anaphora: that is, surface anaphora, such
as VPE, is more sensitive to such parallelism than deep anaphora (VPA) and VPE is
often judged as less acceptable than VPA following nonparallel antecedents (see 1
above). In fact, a corollary of the Sag and Hankamer account is that the parallelism
effect should not obtain in (semantically equivalent) VPA constructions, such as those
in (2), since they claim that VP-anaphors are interpreted via discourse processing
mechanisms, rather than via a syntactic copying mechanism, as proposed for VPE. In
processing terms, a parallelism effect would be evidence that an anaphoric clause with
a nonparallel antecedent would take longer to process than one with a parallel
antecedent. However, as with the other antecedent manipulations, Murphy (1985)
found no difference between the processing of VPE and VPA with parallel and
nonparallel antecedents, and so these results do not support the predictions of the Sag
and Hankamer’s (1984) account.4
In contrast to Murphy’s results, the alleged asymmetry in parallelism between
VPE and VPA was empirically supported by Tanenhaus and Carlson (1990) who
used a timed Sentence Completion Judgment task (SCJT) to investigate the effects
of syntactic parallelism on VPE and VPA respectively, and contrasted two types of
nonparallel structure: PASSIVE antecedents, as in the examples in (1b)/(2b); and
NOMINAL antecedents, as in (1d)/(2d). See note 1 above. Consistent with Sag and
Hankamer’s account, and in contrast to Murphy (1985), a reliable parallelism effect
was observed for VPE completions across both constructions (1a vs. 1b, 1c vs. 1d), but
only a numerical difference and not a statistically reliable parallelism effect for VPA
completions (see also Mauner, Tanenhaus, & Carlson, 1995, for short vs. long
passives). However, different results were observed in studies by Duffield, Matsuo, and
Roberts (2009) and Duffield and Matsuo (2009), even though they used a very similar
task and materials to those of Tanenhaus and colleagues. Duffield et al. found reliable
parallelism effects for VPA constructions as well as for VPE, although the effects were
indeed much smaller.
Using an on-line verification task, Bélanger (2004) reported that the two anaphor
types appeared to be processed differently. Manipulating the distance between the
elided clause and the sentence requiring the verification response, Bélanger found that
latencies were significantly longer only in the VPE constructions with nonparallel (8b)
antecedents and not in the VPA conditions.
(8)
a. The travel agent messed up Frank’s booking. He was very disappointed that she
(did/did it).
b. The travel agent messed Frank’s booking up. He was very disappointed that she
(did/did it).
4
For VPE at least, these results are also supportive of recent semantic accounts that assume that VPellipsis with voice mismatches are underlyingly grammatical (Merchant, 2007, 2008; Tanaka, 2011; see notes
1 and 11).
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PROCESSING VP-ELLIPSIS AND VP-ANAPHORA CLAUSES
5
It may be that task sensitivity underlies the different patterns of results found in the
above-reported set of studies. That is, the SCJT used by Tanenhaus and Carlson (1990)
and Duffield et al., the sentence reading times gathered by Murphy, and the
verification task by Bélanger all can be argued to tap into later, interpretative
processing rather than into more immediate, incremental processing. A study relevant
to the one we present here, and one that has focused on the processing at the elision
site itself, is a recent event-related potential (ERP) study by Callahan, Nicol, Love,
and Swinney (2007). The authors found very similar waveforms elicited by readers’
plausibility judgments to sentences such as The player shuffled the deck at the
beginning of the game and the (dealer/fortune) (did/did it) too. Therefore, although
a larger processing cost for VPE than for VPA at the elision site was in evidence,
the results do not provide strong evidence that VPE and VPA are interpreted via
different processing mechanisms, at least for grammatical constructions and those
with syntactically parallel antecedents. The authors did not, however, investigate the
processing of VPE and VPA with structurally nonparallel antecedents, and so it is still
not clear whether the processor handles the two anaphor types differently in real-time
comprehension.
Returning to the presence/absence of the parallelism effect, there are in fact
independent theoretical and psycholinguistic reasons for doubting that syntactic
parallelism is a necessary property of VPE, as claimed by Sag and Hankamer. First,
research into the processing of many different types of construction has found a
general processing preference for parallel structure. For instance, when reading
coordinate sentences (e.g., Frazier, Munn, & Clifton, 2000; Frazier, Taft, Roeper, &
Clifton, 1984), the second conjunct in and-coordinations is read significantly faster
when it is structurally parallel to the first conjunct (9a) than when it is not (9b).
(9)
a. The tall gangster hit John and the short thug hit Sam.
b. The tall gangster was hit by John and the short thug hit Sam.
Similar effects have been observed in coordinated constructions where the first
conjunct differs along other types of structural dimensions, such as subject and object
word order (Knoeferle & Crocker, 2009), as well as for semantically nonparallel first
conjuncts (animacy, e.g., Frazier et al., 1984; noun-phrase similarity, Knoeferle &
Crocker, 2009). It appears in fact that parallelism effects may be additive, given that
the results of the eye-tracking study by Knoeferle and Crocker (2009) which showed
strongest effects when both syntactic and semantic information were parallel.
Furthermore, in an eye-tracking study, Frazier et al. (2000) found parallelism effects
for coordinated structures even when nonparallel versions had been rated as
acceptable as the parallel constructions. Thus there are across-the-board parallelism
effects reported above in a range of processing studies (see also Callahan, Shapiro, &
Love, 2010).
The semantic parallelism findings in these processing studies would perhaps be
predicted by some semanticists*most notably Dalrymple, Shieber, and Pereira (1991)
and Hardt (1993)*who have drawn attention to the fact that apparent violations
of parallelism occur more commonly in spontaneous speech than would be expected
if such sentences were truly ungrammatical. Representative examples are given
in (10):
(10)
a. A lot of this material can be presented in a fairly informal and accessible fashion,
and often I do. (Chomsky 1982, cited in Dalrymple et al.). [Hardt (134)]
6
ROBERTS, MATSUO, DUFFIELD
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b. We should suggest to her that she officially appoint us as a committee and invite
faculty participation. They won’t, of course . . . (University of Pennsylvania
Email message) [Hardt (116)]
In fact, one of the more influential of the semantic proposals is that VPE
constructions should be analysed instead as ‘‘VP-Pronouns’’ (e.g., Dalrymple et al.,
1991; Hardt, 1993; also Culicover & Jackendoff, 2005). Under this ‘‘proform’’ theory
of VPE, elided VPs are treated as referential expressions with no internal structure: the
conditions that apply to VPE clauses would therefore be the same as those that apply
to other proforms, such as pronouns. On this approach, VPE does not require a
structurally parallel antecedent; rather it must be identified semantically with its
antecedent. Of course, the more semantic features that are shared by the elided and
antecedent clauses, the easier the identification process is. Thus, this strict semantic
account predicts that parallel antecedents should be preferred over nonparallel
antecedents for elided clauses, but crucially, it predicts no difference between VPE and
VPA in terms of how the elided clause is linked to its (conceptual) antecedent: the two
ellipsis-types are both treated as ‘‘VP-pronouns’’. A processing account relying on
accessibility of the antecedent (e.g., Ariel, 1990; Givón, 1984) would therefore be
applicable here. Any differences between VPE and VPA under this account could be
attributed to the fact that like null pronouns, VPE may need a more restricted
antecedent, whereas like overt pronouns, VPA might be more flexible in this regard.5
In the majority of the studies investigating the processing of VPE versus VPA
reported above, although testing on-line processing, the researchers required their
readers to make some kind of judgment during the processing of the experimental
items, and it is not clear what effect this might have on the real-time linking of the
elided clause with the antecedent clause. In fact, it is possible that making a judgment
increases the likelihood of finding a parallelism effect for both VPE and VPA, given
that when Murphy (1990) elicited timed judgments from readers, in contrast to his
(1985) study, he found a difference between the anaphor types, with longer judgements
latencies for VPE versus VPA constructions. It is not clear, however, why such task
effects might be in evidence, nor why inconsistent results should be found across
studies even when the tasks are similar.
In sum, the processing evidence taken together suggests that parallelism may be an
across-the-board parsing phenomenon, and therefore one might expect it to be in
5
Murphy (1985) notes that in VPA, the pronoun refers to a discrete action, entity or event (ib) and is
much less ambiguous than VPE (ic), for which there is a larger number of possibilities overall of potential
antecedents.
(i) a. Jean saw the accident.
I thought Chris did.
*I thought Chris did it.
b. Does Mary eat meat?
No, but Ed does.
*No, but Ed does it.
c. Jane saw Fred pull the plug.
I thought Amy did. (ambiguous)
I thought Amy did it. (unambiguous)
Similarly, in Lasnik’s analysis (1999a, 1999b), a distinction is made between main verbs and auxiliaries, with
the latter subject to strict formal identity conditions (e.g., *John has left but Mary shouldn’t), in contrast to
the former, where ‘‘sloppy identity’’ appears to be at work (e.g., John slept and Mary will too). It is not clear
from current research how much effect such differences may have on the real-time linking processes in VPA
versus VPE.
PROCESSING VP-ELLIPSIS AND VP-ANAPHORA CLAUSES
7
evidence for both anaphor types in VPE and VPA.6 However, given the mixed findings
from the range of psycholinguistic experiments reported above, more research is
clearly needed to investigate the processing of VPE and VPA constructions with
parallel and nonparallel antecedents. In particular, to see (a) whether the two types of
anaphor are processed differently at the elision site when the task requires reading for
meaning, rather than in order to make a judgment, and (b) whether a parallelism
effect is observed and to the same extent for both anaphor types.
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THE CURRENT STUDY
The following specific questions were investigated:
i. Are parallel and (syntactically) nonparallel VPE and VPA constructions
processed differently online?
ii. Is there an observable parallelism effect for either VPE and VPA constructions
in real-time processing, and if so, what is the time-course of the parallelism
effect?
Predictions
The syntactic account (e.g., Sag & Hankamer, 1984) predicts that the two anaphor
types should be processed differently, since surface anaphora like VPE is assumed to
be interpreted with reference to the linguistic level (for instance, employing a syntactic
copying mechanism), whereas VPA would be interpreted via discourse processing
mechanisms. This in turn predicts that parallelism effects should be in evidence
only between parallel and nonparallel VPE constructions. The semantic account
(Dalrymple et al., 1991, Hardt, 1993) treats both anaphor types as ‘‘VP-pronouns’’,
and thus should be interpreted via the same mechanism and predicting a parallelism
effect for both VPE and VPA constructions, and no significant processing difference
between ellipsis-types in general (at least across parallelism conditions).
Participants
A group of 15 English native-speakers (9 women; mean age: 38.4; SD: 10.7; range: 28
61) took part in the study. All had normal or corrected-to-normal vision, and were
paid a small fee for their participation.
Materials
The experimental materials comprised 24 texts, exemplified in (11) and (12). See
Appendix for the full set. Each critical sentence*comprising an antecedent clause
followed by an elided clause*was set in a short text and in each, the syntactic
parallelism of the antecedent clause (parallel, a/b; nonparallel, c/d) and the anaphor
type of the second clause (VPE, a/c; VPA, b/d) was manipulated. For half of the
experimental items (n 12), the nonparallel antecedent clause contained a passive
verb, as in (11c, d); in the other half, it was a derivationally related nominal (12c, d):
(11)
6
Active-Passive Antecedents
It was snowing very heavily last night,
We thank an anonymous reviewer for this suggestion.
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8
ROBERTS, MATSUO, DUFFIELD
a. but someone took the wood out to the shed. Tom told us that Sally did.
b. but someone took the wood out to the shed. Tom told us that Sally did it.
c. but the wood was taken out to the shed. Tom told us that Sally did.
d. but the wood was taken out to the shed. Tom told us that Sally did it.
I was surprised that she was so kind.
(12) Verbal-Nominal Antecedents
There is a great discrepancy of wealth in the US.
a. Someone robbed CitiBank as an act of desperation. The police haven’t figured
who did.
b. Someone robbed CitiBank as an act of desperation. The police haven’t figured
who did it.
c. The robbery at CitiBank was an act of desperation. The police haven’t figured
who did.
d. The robbery at CitiBank was an act of desperation. The police haven’t figured
who did it.
The bank remained open for the rest of the year.
out
out
out
out
The two sets of experimental items (Active-Passive and Verbal-Nominal) were
constructed, each in the four experimental conditions shown in (11) and (12) above
(parallel/nonparallel antecedents and VPE/VPA clauses): these items were then
pseudo-randomised and set within 60 filler texts of different types. Four experimental
stimuli lists were created such that no participant saw any item from the same
experimental set more than once.
Procedure
Given that the aim of the experiment was to investigate the time course of VPE and
VPA processing, eye tracking during reading was used. It was assumed that the longer
a participant spends reading the critical region*here, the verb in the elided clause and
the verb plus pronoun in the VPA conditions (did/did it)*the more (comparatively)
difficult the process of linking the elided clause is to its antecedent clause. Therefore,
more time spent reading the verb in a elided clause following a nonparallel antecedent
(c/d above) in comparison to the corresponding item following a parallel antecedent
was taken as an indication of processing difficulty, and therefore as evidence of a
parallelism effect in processing.
The experiment was run using an Eyelink II head-mounted eye tracker. During the
experiment, recordings were taken from both eyes but only the locations of the right
eye were analysed. Gaze location was monitored every 2 ms, and the positions of eye
fixations and their start and finish times were established by the tracker’s software.
Each person was tested individually in a dedicated experiment room; they sat
approximately 60 cm in front of a computer screen on which the experimental texts
were presented. At the beginning of the experiment, the participant fixated a series of
squares which appeared at different points on the screen in order to test the accuracy
of calibration; this procedure was repeated until accuracy was achieved. Following
calibration, the experiment began. Each experimental text and filler material was
presented on-screen and each was followed by a comprehension question that required
a yes/no response, recorded via a button push on a dedicated button-box (right button
for a ‘‘yes’’, left for a ‘‘no’’ response). None of the comprehension questions concerned
the experimental manipulation, and they were included merely to ensure (as far as
possible) that the texts were read for meaning. Following the participant’s response to
the comprehension question, the text disappeared, and was replaced by a dot in the
centre of the screen, at which point the experimenter checked the calibration of the eye
PROCESSING VP-ELLIPSIS AND VP-ANAPHORA CLAUSES
9
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tracker, and if successful, pushed a button that brought up the next text on the screen.
The texts were presented with two blank lines in between each line of text in order to
aid later fixation analysis. The critical segment (the auxiliary/and pronoun) was
presented as centrally on the screen as possible, and care was taken to ensure that it
never appeared at the beginning or the end of a line, because the eyes rarely land at the
extreme left or right far edge of the screen (Rayner, Juhasz, & Pollatsek, 2005).
Accuracy for the comprehension questions was high, at 91.4% (SD5.3). One
participant was excluded from further analyses because she/he scored two standard
deviations below the group’s mean (79%) and so we could not be sure that she/he had
paid attention during the reading task.
Data analyses
All fixation points shorter than 100 ms were incorporated into the immediately
following or immediately preceding fixation if they fell within one character space
of this fixation. All other fixations of less than 100 ms were removed from the
analyses: this is because it is not clear whether readers can gather much information
during these very short fixations (Rayner & Pollatsek, 1989). This procedure affected
3% of the data.
A number of different eye-movement measures were gathered, including first
fixations, first pass and regression path durations: these are the measures thought to
reflect the very earliest stages of the reading comprehension process. A first fixation is
the first time the eyes land in the critical region. First pass fixation durations are
calculated by summing the first fixation and any subsequent fixations in the critical
region from the first time the eyes enter the region from the left until the eyes leave,
either to the right or the left. Regression path durations include the first pass fixation
durations plus any subsequent fixations if the eyes leave the critical region to the left in
order to reread earlier portions of the text, until the eyes move past the critical region
to the right. This measure is assumed to be one of the first-pass measures because the
regression path is instigated by the first reading of the critical region, and therefore it
is thought to be indicative of early processing difficulty. This assumption is made in
spite of the fact that the total reading times of such regression paths might be very
high, if the reader has reread much of the earlier parts of the text (Pickering, Frisson,
McElree, & Traxler, 2004).
Measures assumed to reflect later processing were also recorded: second pass and
total fixation duration times. Second pass fixation times are calculated by summing
those fixations where the reader returned to the critical region (having exited it to the
right) in order to reread it for a second time. If this does not occur, then a zero is
entered into the data table, which is why total second pass fixation durations are often
much shorter than other fixation durations (Sturt, 2003). Total fixation durations are
calculated by summing all the fixations on the critical region, from the first to the very
last: this sum might include fixations where the reader has reread the critical region for
a fourth or fifth time. These later eye-movement measures are assumed to tap into
later, integrative reading comprehension processes (Pickering et al., 2004).
In all analyses of the eye-tracking data, we employed linear mixed-effects models
using the lmer function in the lme4 package in R (Bates & Maechler, 2009), with
subjects and items as random effects (Baayen, Davidson, & Bates, 2008). The fixed
effects were the factors Antecedent Type (active-passive/verbal-nominal), Anaphor
Type (VPA/VPE) and Parallelism (parallel/nonparallel), and the dependent variable
was log-transformed fixation times. A stepwise selection procedure was fitted for each
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ROBERTS, MATSUO, DUFFIELD
model where factors were removed which failed to reach at least pB.10 (Luke &
Christianson, 2011). Significance was estimated with Markov-Chain Monte Carlo
(MCMC), reported as p(MCMC).
Table 1 presents the averaged fixation time data for the reading of the critical region.
Looking first at the early processing measures*first fixation, first pass and
regression path fixation durations*it can be seen that the participants spent longer
reading the VPE conditions overall in comparison to the VPA conditions, irrespective
of type of antecedent (active-passive/verbal-nominal). This is supported by
the statistical analyses in which the factor Antecedent Type was removed from the
models because it did not contribute to the fit of the data. For all early measures, there
was a significant main effect of Anaphor Type: First Fixation (228 vs. 252 ms:
b0.073, SE 0.025, t2.87, pMCMC B.01), First Pass (249 vs. 287 ms: b 0.088,
SE 0.029, t3.05, pMCMC B.01), Regression Path Durations (255 vs. 333 ms:
b0.121, SE 0.031, t3.87, pMCMC B.001). Thus, the effect of Anaphor Type
was the case irrespective of whether or not the antecedent clause was syntactically
parallel, and even though the critical region in the VPE constructions comprised only
one word (e.g., the verb did) in contrast to the VPA conditions, which contained the
verb plus the pronoun (did it). This suggests that at the earliest point in the
comprehension process, processing VPE constructions is computationally more costly
than processing VPA overall. In the Regression Path analyses, there was also a
significant main effect of Parallelism (b 0.0713, SE0.033, t2.20, pMCMC B.05)
and a significant interaction between Anaphor Type and Parallelism (b 0.106,
SE 0.045, t2.33, pMCMC B.05). In a posteriori contrasts, this effect of
Parallelism was tested for each type of anaphor and a significant effect was found
for VPA (232 vs. 276 ms: b0.0656, SE 0.031, t2.15, pMCMC B.05) which was
not in evidence in the comparison between the VPE conditions (parallel vs.
nonparallel: 332 vs. 327 ms; p’s .3). Thus at the early stages, readers processed the
two anaphor types differently, both with parallel and nonparallel antecedents.
In the later reading time measures, as in the analyses of the earlier fixation times,
the factor Antecedent Type was removed from the model for these measures because it
did not contribute to the fit of the data. Again, the VPE conditions overall took longer
to read than the VPA conditions and this was reflected in the main effect of Ellipsis, in
the Second Pass fixation times (b 0.365, SE 0.171, t 2.130, pMCMC B.05).
There was also a significant interaction between Anaphor Type and Parallelism in
both Second Pass Fixations (b0.790, SE 0.248, t3.182, pMCMC B.001) and
Total Fixations (b 0.116, SE 0.058, t 2.00, pMCMC B.05). In contrast to what
TABLE 1
Mean fixation durations (and standard deviations) in milliseconds on the critical region
First
First pass
Regression
path
Second
pass
Total
Active
VPA
Passive
VPA
Active
VPE
Passive
VPE
Verbal
VPA
Nominal
VPA
Verbal
VPE
Nominal
VPE
226 (78)
243 (94)
261 (131)
241 (102)
264 (111)
277 (121)
248 (72)
288 (109)
303 (126)
244 (110)
277 (170)
348 (371)
203 (59)
216 (73)
211 (76)
234 (91)
265 (126)
267 (115)
270 (133)
281 (134)
371 (358)
250 (101)
305 (145)
306 (245)
92 (159)
61 (114)
21 (57)
87 (141)
62 (111)
57 (110)
65 (140)
171 (310)
365 (261)
343 (207)
316 (133)
404 (260)
288 (157)
333 (181)
392 (288)
526 (413)
Note: VPA, VP-anaphora; VPE, VP-ellipsis.
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was observed in the early processing measures, the parallelism effect was now observed
in the comparison between the VPE conditions (second pass fixations: b 0.638,
SE 0.174, t3.67, pMCMC B.001; total fixations: b 0.099, SE0.041, t2.44,
pMCMC B.05) and there was no difference (thus no parallelism effect) between the
two VPA conditions in either Second Pass (parallel 77 ms vs. nonparallel 55 ms:
p’s .3) or Total Fixation times (parallel 330 ms vs. nonparallel 333 ms: p’s .5).
In sum, from early on in the comprehension process, participants spent longer
reading VPE than VPA items overall, irrespective of syntactic parallelism, suggesting
that more processing cost in general is incurred with VPE versus VPA constructions,
even at the earliest stages of linking an elided clause with its antecedent. Parallelism
effects were, however, observed on the critical region although, these differed
according to Anaphor Type and according to timing. At the earliest stages, a
parallelism effect was found only between the VPA conditions: the parallel VPA
condition was read more quickly than the nonparallel VPA condition. In later reading
time measures, a parallelism effect was observed between the VPE conditions, and not
between the VPA conditions, where parallel and nonparallel conditions elicited almost
exactly the same reading times.
In order to investigate any later occurring effects, we also examined the reading
time data in the postcritical region, defined as the two words immediately downstream
from critical region. The analyses were performed on the data from 19 of the 24 items
in which the postcritical region was the beginning of a new sentence. The mean
fixation times are given in Table 2.
Overall the participants read the postcritical region more slowly in the nonparallel
conditions. This was supported by a significant main effect of Parallelism, when the
other two factors (Antecedent Type and Anaphor Type) were dropped from the
model, for First Pass (224 vs. 236 ms: b 0.0641, SE 0.0274, t2.34,
pMCMC B.05), Second Pass (99 vs. 174 ms: b 0.3993, SE 0.1445, t2.76,
pMCMC B.01), and Total Fixations: 471 vs. 632 ms: b0.1269, SE 0.0318,
t3.99, pMCMC B.001).
In contrast to the processing of the critical region, the type of antecedent (active/
passive and verbal/nominal) affected the earliest stages of processing in the postcritical
region. For regression path times, in a model including all three factors, the best fit
was that which found a significant interaction between Antecedent Type and Anaphor
Type (b0.159, SE 0.0803, t1.98, pMCMC B.05). This interaction was caused by
the fact that the participants more often went back and spent longer rereading the
earlier parts of the text in the Verbal-Nominal VPE (460 ms) versus the VerbalTABLE 2
Mean fixation durations (and standard deviations) in milliseconds on the postcritical region
First
First pass
Regression
path
Second
pass
Total
Active
VPA
Passive
VPA
Active
VPE
Passive
VPE
Verbal
VPA
Nominal
VPA
Verbal
VPE
Nominal
VPE
227 (69)
329 (196)
345 (196)
234 (79)
367 (206)
398 (250)
218 (66)
284 (110)
284 (110)
264 (249)
404 (334)
432 (365)
191 (59)
340 (292)
340 (292)
225 (83)
347 (196)
367 (203)
222 (64)
391 (265)
395 (264)
239 (107)
422 (233)
525 (314)
94 (160)
162 (356)
111 (171)
211 (247)
85 (135)
113 (205)
27 (79)
184 (221)
452 (327)
621 (600)
421 (236)
660 (480)
458 (364)
471 (231)
450 (361)
662 (365)
Note: VPA, VP-anaphora; VPE, VP-ellipsis.
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ROBERTS, MATSUO, DUFFIELD
Nominal VPA condition (353 ms) (b0.1257, SE 0.0524, t2.40, pMCMC B.05),
whereas there was no significant difference between the two Anaphor Types in the
Active-Passive sentences (VPE 358 ms vs. VPA: 372 ms; p’s .5). As can be seen in
Table 2, the Nominal VPE condition elicited the greatest processing times of all
conditions in the Regression Path Time measures (525 ms).
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DISCUSSION
The aim of this study was to investigate (1) the linking process between the elided and
the antecedent clause in real time comprehension, in particular, how the processor
copes when faced with superficially nonparallel antecedent clauses; and (2) the relation
between two type of anaphors VPE and VPA and the antecedent. The results of this
study can be summarised as follows.
Analysis of the earliest reading time measures found:
. overall the VPE items took longer to read than the VPA constructions
(irrespective of the surface parallelism of the antecedent clause, and in spite of
the fact that the critical region for VPA was longer by one word7);
. a reading time advantage for the VPA-parallel condition overall;
. a parallelism effect*higher reading times on the elided clause items with
(surface) nonparallel antecedent clauses compared with those with parallel
antecedent clauses*only in the comparison between the VPA items.
. In the later reading time measures:
. again, an overall processing disadvantage for VPE versus VPA,
. a parallelism effect for VPE, but not VPA.
In the postcritical region:
. regression path times showed that, irrespective of surface parallelism, readers
spent more time rereading the critical region and earlier parts of the text in the
Verbal-Nominal-VPE than the Verbal-Nominal VPA conditions, and no such
difference between anaphor types was observed in the Active-Passive conditions;
. in both early and late measures, there was an overall effect of syntactic
parallelism, with higher reading times for sentences with nonparallel versus
parallel antecedents, irrespective of antecedent or anaphora type.
These findings are discussed below.
One of the research questions that we set out to address was whether VPE in
general elicits a different processing cost from VPA at the elision site. The answer is
both yes and no. As in Duffield et al. (2009) and Duffield and Matsuo (2009), we
found a parallelism effect for both VPE and VPA, even though the participants were
reading the experimental items for comprehension, rather than being required to make
any judgments which could be argued to focus attention on structural differences.
Therefore, these results do not support the strong syntactic account of Sag and
Hankamer (1984) and their claim that syntactic parallelism is uniquely associated with
7
Although the critical segment was indeed one word longer in the VPA conditions, the pronominal was
fixated only 25% of the time (as is often the case when reading ‘‘functional’’ versus lexical elements, Rayner,
Juhasz, & Pollatsek, 2005). When these fixations are not included, the results remain the same.
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VPE. However, given that we observed some striking differences in the processing
between the VPE and VPA constructions, the results also run contrary to the strong
prediction of semantic accounts that would predict no difference between the two
anaphor types (Dalrymple et al., 1991; Hardt, 1991). It may be that our data support a
one mechanism, accessibility account of anaphor processing (e.g., Ariel, 1990; Givón,
1995); we return to this below.
The most important finding of this study was the difference found between the
processing of the two construction types in both strength and timing. VPE clauses
took longer to process at the earliest stages, as well as overall in comparison to the
VPA clauses, even though in the latter conditions the critical region contained one
extra word (the pronoun). Although one should be cautious in interpreting the causes
of such effects, one potential reason for this timing difference is that in general more
computational work needs to be undertaken in the interpretation of VPE versus VPA
at the gap site itself, and at the very earliest stages of interpretation. Since this
difference was observed in the processing of VPE and VPA irrespective of antecedent
type or antecedent parallelism, and despite the longer critical region in the VPA
constructions, it is unlikely that the effect can be attributed to the antecedent clause.
Rather, this effect seems to be caused by the difference in the processing of the elided
clauses themselves (VPE vs. VPA). Note that a similar processing cost was observed in
the ERP data by Callahan et al. (2007) in their comparison between (structurally
parallel) VPE and VPA constructions.
Another interesting difference observed between the construction types was the fact
that the parallelism effect was in evidence for VPE in later reading time measures,
whereas it was present very early for VPA. These timing differences in the processing
of the elided clauses in VPE and VPA in turn suggest that the process of linking the
elided clause with its antecedent in VPE may not be identical to that linking the two
clauses in VPA. This raises the question of how to account for this difference.
It is possible that the differences we observed reflect a fundamental difference
between the processing of the two anaphor types: in other words, it may be that in
VPE, but not in VPA, the antecedent VP is reactivated at the elided VP gap site (cf.
the copy mechanism of Frazier & Clifton, 2001). Another possibility is that both
VPE and VPA are linked to the preceding clause by the same mechanism, much
like pronoun resolution (and subject to accessibility, e.g., Ariel, 1990; Givón, 1995)
where it is observed that immediately on encountering a pronoun in the input, the
parser looks for some semantic features that will allow the referential expression to
pick out its antecedent in the earlier clause (Nicol & Swinney, 2002). In that case,
the earlier processing effort we observed in VPE could be attributable merely to the
detection of a gap, which is not present in VPA.8 We discuss these alternatives
below.
If the parser reactivates/reconstructs the antecedent VP at the elision site in VPE,
then it can explain why VPE overall was more costly than VPA at the earliest stages
of processing, and why any processing difficulty was observed only in later
processing measures which are thought to reflect integration. In fact, the ‘‘VPRecycling Hypothesis’’ of Arregui, Clifton, Frazier, and Moulton (2006) offers an
explanation as to the parsing procedures that might be at work specifically in VPE
(although it does not specify how VPA might be processed). According to this
account, at the gap site, the parser postulates an empty VP and then searches for an
antecedent VP in the earlier context. On finding it, the VP is copied at the gap site,
8
We thank an anonymous reviewer for this suggestion.
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ROBERTS, MATSUO, DUFFIELD
and if it is not a perfectly suitable (parallel) antecedent, repair processes come into
play which fix it (in grammatically constrained steps) until it is. The more steps
required to make the necessary adjustments to the VP to create a parallel
antecedent, the more difficult the process (and the comparably less acceptable the
resulting sentence is). For instance, the parser finds it very easy to merely change
tense from [] to [] (John left and Bill did [leave] too) whereas far more steps are
needed in order to create a VP from an antecedent in which no VP is present, such
as in the nominal nonparallel items in the current study: this operation would entail
changing nominal features into verbal features*requiring many more steps.9
Relevant findings from recent studies investigating how much of the antecedent
might be accessed in the processing of VPE and sluicing constructions offer support
to this account of VPE processing. For instance, in a cross-modal lexical priming
study, Shapiro, Hestvik, Lesan, and Garcia (2003) found that only the object NP of
the antecedent VP was reactivated in the ellipsis clause in constructions like The
mailman bought a tie for Easter, and his brother did too. (see also Poirier, Wolfinger,
Spellman, & Shapiro, 2010). Therefore it seems that it is not the whole antecedent
clause that is reactivated, but only the linguistic material that is grammatically
appropriate. However, whether or not this occurs with VPA is not clear, given that
similar findings have been reported in the processing of pronouns. For instance,
Nicol (1988) found that where there was more than one antecedent in the discourse,
the processor activates only the syntactically relevant one. It would be highly
interesting to investigate comparable VPA constructions to those VPE items used by
Shapiro et al. in a cross-modal lexical priming study to see how much of the
antecedent clause is reactivated at the elision site. One could also test the timing
reactivation effects of VPA versus VPE, given priming findings showing that the
reactivation of the antecedent verb may take place more immediately when the
construction contains a ‘‘cue’’ to indicate parallelism (e.g., in and-co-coordinated
sentences) (cf., Callahan et al., 2010; Knoeferle & Crocker, 2009).
Martin and McElree (2008) argue against the idea that the VP is reconstructed at
the gap site. They investigated the time-course of interpreting VPE clauses which
differed in the complexity of the antecedent VP. Using the speed-accuracy trade-off
methodology, the authors found that although accuracy decreased as the complexity
of the antecedent VP increased, the time it took for participants to interpret the
items at the elision site was not affected by complexity. The authors argue therefore
that the memory mechanism that underlies VPE processing is one of direct access,
rather than a ‘‘serial search’’ mechanism, and thus they argue that a copying
account of VPE resolution is not tenable. Our data cannot help to decide between
competing accounts of memory processes that may underlie VPE processing, and it
9
This analysis of VPE is different to that of Merchant (2007, 2008), in that Arregui et al. assume that
VPE with a voice-mismatched antecedent is ungrammatical (and the parser works in grammatically
constrained steps to ensure a syntactically parallel structure) whereas in Merchant’s account, such voicemismatches should be grammatical (see also Tanaka, 2011; and note 1 above). Taking these processing
findings and those that show that VPE with nonparallel voice-(mismatch) antecedents elicit degraded
acceptability judgments (e.g., Duffield, and colleagues; Kim & Runner, 2009) there is clearly a processing
cost at the elision site. What exactly occurs is open to interpretation. If the Tanaka/Merchant account is
correct, this would involve a change of feature-values in the [voi] head, and not reconstruction, which would
be the case if one assumes the traditional, underlyingly ungrammatical analysis for nonparallel VPE. A
future study focusing on the graded acceptability of VPE versus pseudogapping constructions would prove
highly interesting.
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is certainly possible that a content-addressable mechanism is responsible for
processing VPE clauses.10
Similarly, it is possible that anaphor resolution employs the same mechanism in
both anaphor types, and that the processing differences observed can be accounted for
in terms of differences in the accessibility of the antecedent VP (Ariel, 1990; Givón,
1995). In other words, like the processing differences observed between null and overt
pronouns, VPE may require a closer antecedent than VPA. Coupled with the idea that
the initial processing cost observed for VPE was incurred because of the detection of
the gap in the input, this could account for our results: weaker and more fleeting
parallelism effects for VPA versus VPE and immediate effects of parallelism for VPA.
On-line pronoun resolution is assumed to be an immediate process, in that as soon as
a pronominal is met in the input, a search for a suitable antecedent in the earlier
discourse is initiated (Garrod, Freudenthal, & Boyle, 1994; Gordon & Scearce, 1995;
Nicol, 1988; Shillcock, 1982; but compare Greene, McKoon, & Ratcliff, 1992). As
noted in the introduction, parallelism has been observed in many different contexts,
and has been found to help pronoun resolution (Chambers & Smyth, 1998). So, this
single mechanism account fits with much of our data. However, recall that analyses of
the postcritical region found that in regression path times, nominal VPE antecedents
were more difficult to process than nominal VPA and passive antecedents overall.
Although statistically robust by subjects only, it is not clear how such a difference in
the processing of nonparallel antecedent types between VPE and VPA would be
accounted for with a general accessibility mechanism. Although accessibility can
account for differences in the strength of parallelism in VPA versus VPE, if one
assumes that VPA can tolerate more distant and less parallel antecedents than VPE, it
is unclear how a nominal nonparallel antecedent would be less accessible than a
nonparallel passive antecedent in VPE contexts, but not in VPA contexts. Therefore,
much more research on the processing of VPE and VPA constructions with various
types of nonparallel antecedent clauses is clearly required.11
10
One reason that our results cannot arbitrate between these two accounts of VPE processing is that our
materials crucially differ from those of Martin and McElree. Specifically, the processing differences
discussed above relate to the processing of VP-ellipsis with syntactically nonparallel antecedents (passive vs.
nominal), unlike those in the Martin and McElree study. Before interpretation can take place, the
comprehender must somehow fix the ungrammaticality and this appears to take more time in the simpler
passive nonparallel versus the nominal nonparallel conditions.
11
As pointed out by an anonymous reviewer, another important influencing factor on VPE, but one that
we did not examine in the current study, is different discourse relations between the antecedent and the
elided clause, following, for instance, Kehler’s (2000, 2002) Coherence Theory (see also Simner, Pickering, &
Garnham, 2003, for do it anaphors). Kehler’s is a hybrid approach to VPE, where under some discourse
conditions, syntactic identity is required (Resemblance relations, e.g., *Jill betrayed Abbey, and Matt was
too), but for others, the antecedent and elided clause need only to match at the propositional level (CauseEffect, e.g., The report was critical of Roy, so Kate didn’t). In the current study, we kept the discourse
relations constant across parallelism and anaphor type conditions, however in terms of the predictions that
can be made on the basis of Kehler’s account, mixed results have been observed. A study by Frazier and
Clifton (2006) specifically tested Kehler’s claim that syntactic parallelism is required for Resemblance but
not for CauseEffect discourse relations and found that that parallelism was preferred under experimental
conditions for all types of coherence relations. Thus the processing predictions of the theory were not
supported. In contrast, Kim and Runner (2009) report that their data from three magnitude estimation
studies show that syntactic parallelism effects are indeed modulated by discourse relations. Furthermore,
information structure-level factors are also likely to affect VPE and VPA (cf., Kertz, 2008), given that in
creating our nonparallel antecedents, a change takes place in the information structure properties of the
antecedent clause, as well as its syntactic structure. Clearly more research is needed to investigate the
interactions between discourse-level and syntactic factors that affect the processing of both VPE and VPA,
and we leave these interesting questions for future research.
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ROBERTS, MATSUO, DUFFIELD
However, as the data currently stand, we would argue that VP-recycling hypothesis
can easily account for the observed differences in relative difficulty (processing cost) of
VPE with nonparallel passive versus the nonparallel nominal items, as well as the
earlier judgment findings of, for example, Duffield et al., where VPE with nominal
antecedents were also considered much less acceptable than those with passive
antecedents. Comparable data to these are in fact found in Arregui et al. (2006), whose
participants judged VPE with a nominal gerund antecedent (e.g., *Tomorrow’s singing
of the arias will be difficult, but Maria will) as much less acceptable than those with a
verbal gerund (?Singing the arias tomorrow will be difficult, but Maria will). In sum,
according to this hypothesis, the easier it is to find a VP antecedent to copy into the
elided gap site, the more acceptable the resulting sentence, and some type of VP in the
antecedent clause is better for the processor than none at all.
Recent evidence in favour of the idea that different linguistic levels may be relevant
for VPE versus VPA comes from Snider and Runner (2010). The authors report that
during the processing of VPE, both phonological and semantic neighbours of words in
the antecedent clause were reactivated, whereas for VPA, it was only semantic
neighbour reactivation that was observed. This can be taken as evidence for the
presence of syntactic structure at the elision site for VPE but not VPA. We argue
therefore that our data, taken together with the results from other such studies, are
consistent with the idea that copying or reconstructing the antecedent VP at the gap
site occurs in VPE but is not necessary for the interpretation of VPA, which is likely to
be a form of pronoun resolution. Therefore, in contrast to VPE, the antecedent for the
pronominal do it in VPA is not a (specific) VP, but rather some (conceptual/semantic)
features contained in the earlier clause, perhaps of the event represented by the VP.
This would explain why no parallelism effect was observed in passive VPA, since the
semantic features of the event are easily picked up, even though the antecedent clause
is not structurally identical. For nominal VPA, on the other hand, the lack of a VP in
the antecedent clause would make this process slightly more difficult, but since the
effect was so transient, it was clearly not a hugely taxing process.
CONCLUSION
The results of the current study, together with findings from earlier research, speak to
issues regarding the processes that appear to underlie the linking of elided clauses with
the antecedent clause in both VPE and VPA. VPE is shown to be more
computationally costly at the earliest stages of interpretation than VPA, lending
support to an account that assumes that the antecedent VP is copied/further processed
at the gap site in VPE (i.e., the VP-Recycling Hypothesis). By contrast, processing the
anaphor clause in VPA is much easier, and any difficulty that occurs is observable
earlier and is transient. Furthermore, nominal VPE antecedent clauses were processed
with more difficulty than nominal VPA. Taken together, this suggests that unlike for
VPE, reconstruction of the elided VP is unnecessary for its interpretation.
Manuscript received 19 November 2009
Revised manuscript received 8 March 2012
First published online 31 August 2012
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APPENDIX
Materials
1 It was snowing very heavily last night, (but someone took the wood out to the shed/but the wood was
taken out to the shed.) (Tom told us that Sally did/Tom told us that Sally did it.) I was surprised that
she was so kind.
2 Mr and Mrs Jones are famous for their antique collection. (John broke the vase belonging to
Mrs. Jones/The vase belonging to Mrs. Jones was broken by John.) She was furious that he did/She
was furious that he did it.) But Mr. Jones stayed very calm.
3 It was such a nice day yesterday. (Jim and his friends organised a picnic/A picnic was organised by
Jim and his friends.) (They were glad that they did/They were glad that they did it.) And they
decided to organise it again.
4 We couldn’t have driven out due to the heavy snow. (But someone shovelled our driveway/But our
driveway was shovelled by someone.) (A neighbour told us that Tom did/A neighbour told us that
Tom did it.) We decided to hire Tom as a snow clearer.
5 There was a big mountain to the south of my hometown. (Nobody had ever climbed it before/It had
never been climbed before.) (Yesterday my friend Sally did/Yesterday my friend Sally did it.) We were
very surprised that she was so fit.
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PROCESSING VP-ELLIPSIS AND VP-ANAPHORA CLAUSES
19
6 Writing a novel that sells well is so hard. (But my brother Sam wrote a best-selling novel/But a bestselling novel was written by my brother Sam.) (Our family was proud that he did/Our family was
proud that he did it.) Now Sam is working on another one.
7 Beef is often more expensive than pork. (But the supermarkets cut the price of beef/But the price of
beef was cut by the supermarkets.) (Everyone was happy that they did/Everyone was happy that they
did it.) Nobody bought pork and chicken after that.
8 Jane had a hard day at work. (When she was out at work, someone stole her stereo/her stereo was
stolen by someone.) (The police asked her if she knew who did/The police asked her if she knew who
did it.) She was happy that she had an insurance that paid for it.
9 Our house needed a lot of repair. (For example, someone had to paint the garage/the garage had to
be painted.) (Finally my younger sister Carol did/Finally my younger sister Carol did it.) My older
brother Tim helped her, too.
10 It’s usually a pop-singer who sings the anthem. (But at this event, an opera star sang it/it was sung by
an opera star.) (People were surprised that he did/People were surprised that he did it.) Other opera
singers were also surprised.
11 Keith tried to set fire to some houses in the town. (Everyone hoped the police would soon arrest him/
Everyone hoped he would soon be arrested by the police.) (Finally, they did/Finally, they did it.)
People said that Keith had to stay in prison for 3 years.
12 There is a big discrepancy of wealth in the US. (Someone robbed CitiBank as an act of desperation/
The robbery at CitiBank was an act of desperation.) (The police haven’t figured out who did/The
police haven’t figured out who did it.) The bank remained open for the rest of the year.
13 There have been a series of robberies in the town. (The police are curious about who robbed the
jewellery store/The jewellery store robbery is a mystery to the police.) (They still don’t know who did/
They still don’t know who did it.) The shop keepers are quite upset by this.
14 During the cold war, there were many defections. (It was bad that the CIA agent exposed important
secrets/The CIA agent’s exposure of important secrets was bad.) (The agency is upset that he did/The
agency is upset that he did it.) They are still trying to repair the damage.
15 Sally and her sister have always been very competitive. (It annoys Sally when anyone mentions her
sister’s name/The mention of her sister’s name annoys Sally.) (However, Tom did/However, Tom did
it anyway) out of spite. Sally stopped talking to him.
16 Mrs. Brown threw a big party last night. (Almost everyone at the party ate far too much food/Far
too much food was eaten by almost everyone at the party.) (Even Mary did/Even Mary did it),
although she was a picky eater. Mrs. Brown was so happy that Mary liked her food.
17 Smokers were unhappy about not being able to smoke at work. (The manager upset them more by
banning smoking in the lounge/The manager’s ban on smoking in the lounge upset them more.) (He
regrets that he did He regrets that he did it). Now people have no other choice than to smoke outside.
18 At the top of the mountain, temperatures drop to 40 degrees. (It would be dangerous to climb that
mountain/A climb up that mountain would be dangerous.) (But my friend Bill did/But my friend Bill
did it.) Although he suffered some frostbite, he was very proud.
19 Tom really wanted to be promoted very fast. (He thought that threatening resignation would have
little effect/He thought that his threat of resignation would have little effect.) (But he did/But he did
it anyway). And he could not believe that it worked!
20 At Mary’s company, people were very supportive. (It annoyed everyone that Mary criticised her boss
constantly/Mary’s constant criticism of her boss was annoying to everyone.) (We didn’t know why
she did/We didn’t know why she did it.) At the end of the year, Mary left the company.
21 Underage drinking is a big problem in this country. (Many accidents resulted from selling alcohol to
minors/The sale of alcohol to minors has resulted in many accidents.) (Many bartenders did/Many
bartenders did it), despite stiff fines. This was extremely irresponsible of them.
22 Sweden is a peaceful place. (The country was shocked when someone assassinated the prime
minister/The country was shocked by the assassination of the prime minister.) (People couldn’t
imagine why anyone did/People couldn’t imagine why anyone did it). The criminal has still not been
found.
23 Bill was a bright child with poor study habits. (It was helpful to him that the teachers discussed these
habits with him/The teachers’ discussion of these habits was helpful to him.) (His mother did/His
mother did it), too on many occasions. Bill appreciated his teachers’ support.
24 Some people want to feel independent. (It can be embarrassing to rely on others for help/Reliance on
others for help can be embarrassing.) (However, there are times when we all do/However, there are
times when we all do it.) This often produces good results.