Brain and Language 102 (2007) 228–242
www.elsevier.com/locate/b&l
Violations of information structure: An electrophysiological study
of answers to wh-questions
a,*
H.W. Cowles , Robert Kluender b, Marta Kutas b, Maria Polinsky b
a
University of Florida, Linguistics, P.O. Box 115454, Gainesville, FL 32611, United States
b
UC San Diego, United States
Accepted 15 April 2007
Available online 22 May 2007
Abstract
This study investigates brain responses to violations of information structure in wh-question–answer pairs, with particular emphasis on
violations of focus assignment in it-clefts (It was the queen that silenced the banker). Two types of ERP responses in answers to wh-ques-
tions were found. First, all words in the focus-marking (cleft) position elicited a large positivity (P3b) characteristic of sentence-final con-
stituents, as did the final words of these sentences, which suggests that focused elements may trigger integration effects like those seen at
sentence end. Second, the focusing of an inappropriate referent elicited a smaller, N400-like effect. The results show that comprehenders
actively use structural focus cues and discourse-level restrictions during online sentence processing. These results, based on visual stimuli,
were different from the brain response to auditory focus violations indicated by pitch-accent [Hruska, C., Steinhauer, K., Alter, K., &
Steube, A. (2000). ERP effects of sentence accents and violations of the information structure. In Poster presented at the 13th annual CUNY
conference on human sentence processing, San Diego, CA.], but similar to brain responses to newly introduced discourse referents [Born-
kessel, I., Schlesewsky, M., & Friederici, A. (2003). Contextual information modulated initial processes of syntactic integration: the role of
inter- versus intrasentential predictions. Journal of Experimental Psychology: Learning, Memory and Cognition, 29, 871–882.].
2007 Elsevier Inc. All rights reserved.
Keywords: ERPs; Focus; N400; Late positivity; Clefts; Information structure
1. Introduction (1) What ate the lettuce in your garden, the deer or the
rabbits?
This study examines the contribution of information a. It was the rabbits that ate the lettuce.
structure to sentence processing by investigating what b. #It was the lettuce that the rabbits ate.
kinds of ERP responses are elicited when focus is incor-
rectly assigned via syntactic structure. The answers that The crucial difference, then, lies not in the content but in
speakers give to wh-questions like (1) are constrained not the form of the answer.
only in terms of their propositional content, but also in This simple example shows that answers to wh-questions
terms of how that content is packaged. (1a) is an acceptable are constrained by information structure, namely the divi-
(if somewhat verbose) answer to the question while (1b) is sion of content into topic and focus. The informative part
not, in spite of the fact that both answers provide the same of an answer to a wh-question must present new or newly
information, namely that the agent of lettuce-eating was activated information, and thus have focus status. Cleft
the rabbits. constructions in particular (1a,b) provide a way to identify
the element in the clefted position as focus (e.g. Lambrecht,
2001; Rochemont, 1986); this is indicated in the example by
means of underlining.
*
Corresponding author. Fax: +1 352 392 0639.
Knowing the nature of the brain’s response to informa-
E-mail address: cowles@ufl.edu (H.W. Cowles). tion structure violations can give us a better understanding
0093-934X/$ - see front matter 2007 Elsevier Inc. All rights reserved.
doi:10.1016/j.bandl.2007.04.004
, H.W. Cowles et al. / Brain and Language 102 (2007) 228–242 229
of the processes that underlie the comprehension of infor- ate the lettuce. Note that the rabbits may elicit particular
mation structure categories like focus; it can also provide processing effects, as it is at this point that a comprehender
insight into the functional significance of the brain can first integrate the new information pertaining to the
response that is elicited. For example, if the answers to referent of this NP into a larger discourse model of who
wh-questions that violate focus constraints were to elicit did what to whom (or, more exactly in this case, what
an increase in N400 amplitude (Kutas & Hillyard, 1980), did what to what). These cleft constructions are known
this would provide evidence that the N400 is sensitive not to be most felicitous in cases where the focus is contrastive,
only to lexico-semantic, morpho-syntactic, pragmatic, that is, when the focus picks out one entity to the exclusion
and world knowledge information (e.g. Bornkessel, McEl- of other possibilities (e.g. it was the rabbits and not the
ree, Schlesewsky, & Friederici, 2004; Federmeier & Kutas, deer—or the gophers or any other animal—that ate the let-
1999; Frisch & Schlesewsky, 2001, 2005; Hagoort, Hald, tuce). In this paper, therefore, we will be dealing with con-
Bastiaansen, & Petersson, 2004; Hopf, Bayer, Bader, & trastive focus in particular.
Meng, 1998; van Berkum, Hagoort, & Brown, 1999), but
also to focus distinctions encoded in the information pack- 3. Mapping processing effects onto possible brain responses
aging of an utterance.
Let us consider what the nature of these processing
2. Linguistic background effects might be, and how they might be reflected in brain
responses. Given that questions such as (1) are typically
Focus is usually defined as that part of an utterance that asked to elicit information that is previously unknown, it
introduces new or newly activated information into the seems safe to assume that cases in which the exact answer
current discourse. Since the status of information as is already expected (based on prior discourse) are relatively
‘‘new’’ is often vague and open to question, focus can be rare. Under more common circumstances, when compreh-
defined operationally as a well-formed answer to a wh- enders are unlikely to have clear expectations about the
(or information) question (e.g. Lambrecht, 1994; Roche- nature of the focused referent, they should nonetheless
mont, 1998; Selkirk, 1996). The wh-phrase introduces an have clear expectations about where in the answer such
open variable that binds the focus portion of the felicitous information will be provided—namely in a syntactically
answer; more informally, the wh-phrase opens up an empty licensed focus position—and what the focus of the answer
slot in the discourse representation built by the listener, cannot be (1b).
and this slot is then filled by the focus portion of the Abstracting away from language-specific issues for a
answer. For example, in (1b), lettuce cannot have focus sta- moment, expectations such as these about general informa-
tus because it cannot be bound by the wh-phrase. In other tion delivery parameters were among the earliest explana-
words, the question in (1) asks for the agent of the lettuce- tions given (Sutton, Braren, Zubin, & John, 1965) for the
eating event, and it is apparent that the lettuce did not eat P300 or P3b component, a centroparietal positivity with
itself. On the contrary, rabbits, deer, or even previously a latency of roughly 250–800 ms post-stimulus onset. A
unmentioned entities like gophers could have focus status broader view of information processing not limited to lan-
in the answer to the extent that they can be construed as guage contexts would thus suggest that the delivery of
lettuce-eaters. information of this sort, i.e. focus status in the answer to
Focus is realized in different, language-specific ways, a wh-question, might be indexed by a P300 or P3b
and it is common to have more than one way of encoding component.
focus in a language (Kiss, 1998; Lambrecht, 1994; Lambr- This prediction is supported by the results of a study
echt & Polinsky, 1997). In English, focus can be marked via investigating the influence of a preceding wh-question on
prosodic contour, as shown in (2), where the pitch accent preferred (subject–object–verb [SOV]) vs. non-preferred
(indicated by capital letters) on rabbits creates a felicitous (object–subject–verb [OSV]) word order options in German
answer in (2a), while the placement of a pitch accent on let- (Bornkessel, Schlesewsky, & Friederici, 2003). Following a
tuce in (2b) does not. wide variety of wh-question contexts (in which case mark-
ing and word order were manipulated relative to both SOV
(2) What ate the lettuce in your garden, the deer or the and OSV target sentences), Bornkessel et al. consistently
rabbits? observed positivity between 280 and 480 ms in response
a. The RABBITS ate the lettuce. to the introduction of any new discourse referent that could
b. #The rabbits ate the LETTUCE. fill the open slot introduced by the wh-phrase of the preced-
ing question, and thereby serve as the focus of the answer.
Focus in English can also be expressed syntactically; one This was true regardless of whether or not the focused ref-
such syntactic construction in English for encoding focus is erent matched the preceding wh-phrase in case-marking
a so-called ‘‘it-cleft’’ (Ross, 1986, pp. 233–234), shown in features (e.g. ‘who’ vs. ‘whom’), and therefore in thematic
(1). role assignment and grammatical function. Bornkessel
This study addresses the processing of focus as embod- et al. tentatively interpreted this positive response as a
ied in it-clefts, for example (1a), It was the rabbits that P3b, although they were troubled by the fact that the same
