John C. Trueswell

The Kindergarten-Path Effect: Studying On-Line Sentence Processing in Young Children.

A great deal of psycholinguistic research has focused on the question of how adults interpret language in real time. This work has revealed a complex and interactive language processing system capable of rapidly coordinating linguistic properties of the message with information from the context or situation (e.g. Altmann & Steedman, 1988; Britt, 1994; Tanenhaus, Spivey-Knowlton, Eberhard & Sedivy, 1995; Trueswell & Tanenhaus, 1991). In the study of language acquisition, however, surprisingly little is known about how children process language in real time and whether they coordinate multiple sources of information during interpretation. The lack of child research is due in part to the fact that most existing techniques for studying language processing have relied upon the skill of reading, an ability that young children do not have or are only beginning to acquire. We present here results from a new method for studying childrens moment-by-moment language processing abilities, in which a head-mounted eye-tracking system was used to monitor eye movements as participants responded to spoken instructions. The results revealed systematic differences in how children and adults process spoken language: Five Year Olds did not take into account relevant discourse/pragmatic principles when resolving temporary syntactic ambiguities, and showed little or no ability to revise initial parsing commitments. Adults showed sensitivity to these discourse constraints at the earliest possible stages of processing, and were capable of revising incorrect parsing commitments. Implications for current models of sentence processing are discussed.

Cognitive control and parsing: Reexamining the role of Broca’s area in sentence comprehension

A century of investigation into the role of the human frontal lobes in complex cognition, including language processing, has revealed several interesting but apparently contradictory findings. In particular, the results of numerous studies suggest that left inferior frontal gyrus (LIFG), which includes Broca’s area, plays a direct role in sentence-level syntactic processing. In contrast, other brain-imaging and neuropsychological data indicate that LIFG is crucial for cognitive control—specifically, for overriding highly regularized, automatic processes, even when a task involves syntactically undemanding material (e.g., single words, a list of letters). We provide a unifying account of these findings, which emphasizes the importance of general cognitive control mechanisms for the syntactic processing of sentences. On the basis of a review of the neurocognitive and sentence-processing literatures, we defend the following three hypotheses: (1) LIFG is part of a network of frontal lobe subsystems that are generally responsible for the detection and resolution of incompatible stimulus representations; (2) the role of LIFG in sentence comprehension is to implement reanalysis in the face of misinterpretation; and (3) individual differences in cognitive control abilities in nonsyntactic tasks predict correlated variation in sentence-processing abilities pertaining to the recovery from misinterpretation.

The effects of common ground and perspective on domains of referential interpretation

Abstract Addressees’ eye movements were tracked as they followed instructions given by a confederate speaker hidden from view. Experiment 1 used objects in common ground (known to both participants) or privileged ground (known to the addressee). Although privileged objects interfered with reference to an identical object in common ground, addressees were always more likely to look at an object in common ground than privileged ground. Experiment 2 used definite and indefinite referring expressions with early or late points of disambiguation, depending on the uniqueness of the display objects. The speaker’s and addressee’s perspectives matched when the speaker was accurately informed about the display, and mismatched when the speaker was misinformed. When perspectives matched, addressees identified the target faster with early than with late disambiguation displays. When perspectives mismatched, addressees still identified the target quickly, showing an ability to use the speaker’s perspective. These experiments demonstrate that although addressees cannot completely ignore information in privileged ground, common ground and perspective each have immediate effects on reference resolution.

Using prosody to avoid ambiguity : Effects of speaker awareness and referential context

Abstract In three experiments, a referential communication task was used to determine the conditions under which speakers produce and listeners use prosodic cues to distinguish alternative meanings of a syntactically ambiguous phrase. Analyses of the actions and utterances from Experiments 1 and 2 indicated that Speakers chose to produce effective prosodic cues to disambiguation only when the referential scene provided support for both interpretations of the phrase. In Experiment 3, on-line measures of parsing commitments were obtained by recording the Listener’s eye movements to objects as the Speaker gave the instructions. Results supported the previous experiments but also showed that the Speaker’s prosody affected the Listener’s interpretation prior to the onset of the ambiguous phrase, thus demonstrating that prosodic cues not only influence initial parsing but can also be used to predict material which has yet to be spoken. The findings suggest that informative prosodic cues depend upon speakers’ knowledge of the situation: speakers provide prosodic cues when needed; listeners use these prosodic cues when present.

The developing constraints on parsing decisions: The role of lexical-biases and referential scenes in child and adult sentence processing

Two striking contrasts currently exist in the sentence processing literature. First, whereas adult readers rely heavily on lexical information in the generation of syntactic alternatives, adult listeners in world-situated eye-gaze studies appear to allow referential evidence to override strong countervailing lexical biases (Tanenhaus, Spivey-Knowlton, Eberhard, and Sedivy, 1995). Second, in contrast to adults, children in similar listening studies fail to use this referential information and appear to rely exclusively on verb biases or perhaps syntactically based parsing principles (Trueswell, Sekerina, Hill, and Logrip, 1999). We explore these contrasts by fully crossing verb bias and referential manipulations in a study using the eye-gaze listening technique with adults (Experiment 1) and five-year-olds (Experiment 2). Results indicate that adults combine lexical and referential information to determine syntactic choice. Children rely exclusively on verb bias in their ultimate interpretation. However, their eye movements reveal an emerging sensitivity to referential constraints. The observed changes in information use over ontogenetic time best support a constraint-based lexicalist account of parsing development, which posits that highly reliable cues to structure, like lexical biases, will emerge earlier during development and more robustly than less reliable cues.

The rapid use of gender information: evidence of the time course of pronoun resolution from eyetracking

Eye movements of listeners were monitored to investigate how gender information and accessibility influence the initial processes of pronoun interpretation. Previous studies on this issue have produced mixed results, and several studies have concluded that gender cues are not automatically used during the early processes of pronoun interpretation (e.g. Garnham, A., Oakhill, J. & Cruttenden, H. (1992). The role of implicit causality and gender cue in the interpretation of pronouns. Language and Cognitive Processes, 73 (4), 231-255; Greene, S. B., McKoon, G. & Ratcliff, R. (1992). Pronoun resolution and discourse models. Journal of Experimental Psychology: Learning, Memory, and Cognition, 182, 266-283). In the two experiments presented here, participants viewed a picture with two familiar cartoon characters of either same or different gender. They listened to a text describing the picture, in which a pronoun referred to either the first, more accessible, character, or the second. (For example, Donald is bringing some mail to ¿Mickey/Minnie¿ while a violent storm is beginning. Hes carrying an umbrellaellipsis.) The results of both experiments show rapid use of both gender and accessibility at approximately 200 ms after the pronoun offset.

Co-localization of stroop and syntactic ambiguity resolution in broca's area: Implications for the neural basis of sentence processing

For over a century, a link between left prefrontal cortex and language processing has been accepted, yet the precise characterization of this link remains elusive. Recent advances in both the study of sentence processing and the neuroscientific study of frontal lobe function suggest an intriguing possibility: The demands to resolve competition between incompatible characterizations of a linguistic stimulus may recruit top–down cognitive control processes mediated by prefrontal cortex. We use functional magnetic resonance imaging to test the hypothesis that individuals use shared prefrontal neural circuitry during two very different tasks—color identification under Stroop conflict and sentence comprehension under conditions of syntactic ambiguity—both of which putatively rely on cognitive control processes. We report the first demonstration of within-subject overlap in neural responses to syntactic and nonsyntactic conflict. These findings serve to clarify the role of Brocas area in, and the neural and psychological organization of, the language processing system.

How words can and cannot be learned by observation.

Three experiments explored how words are learned from hearing them across contexts. Adults watched 40-s videotaped vignettes of parents uttering target words (in sentences) to their infants. Videos were muted except for a beep or nonsense word inserted where each “mystery word” was uttered. Participants were to identify the word. Exp. 1 demonstrated that most (90%) of these natural learning instances are quite uninformative, whereas a small minority (7%) are highly informative, as indexed by participants’ identification accuracy. Preschoolers showed similar information sensitivity in a shorter experimental version. Two further experiments explored how cross-situational information helps, by manipulating the serial ordering of highly informative vignettes in five contexts. Response patterns revealed a learning procedure in which only a single meaning is hypothesized and retained across learning instances, unless disconfirmed. Neither alternative hypothesized meanings nor details of past learning situations were retained. These findings challenge current models of cross-situational learning which assert that multiple meaning hypotheses are stored and cross-tabulated via statistical procedures. Learners appear to use a one-trial “fast-mapping” procedure, even under conditions of referential uncertainty.

The role of thematic structures in interpretation and parsing

Abstract This paper explores how thematic role information associated with verbs is used in language processing. We suggest that thematic roles are useful for co-ordinating different types of information in language processing because they represent aspects of conceptual/semantic representation that map directly on to syntactic form. We review some recent studies investigating the use of thematic information in syntactic ambiguity resolution and present some new evidence that thematic information can be used to eliminate completely the garden path typically associated with reduced-relative clauses. We then review some of our recent work investigating lexical structure in the processing of sentences with long-distance dependencies, and conclude that thematic structure guides the initial interpretation of these sentences. We conclude with a discussion about how thematic information might enable the processing system to make early semantic commitments that take into account relevant aspects of discourse context.

Broca’s Area and Language Processing: Evidence for the Cognitive Control Connection

A long-standing pursuit in cognitive neuropsychology has been to understand the role of Broca’s area in language processing. Although a prevailing view has been to equate this region with grammatical abilities in both production and comprehension, a host of recent evidence from brain imaging and patient research has revealed a rather general role for this patch of cortex in complex cognition, even when grammatical performance is untapped—namely, that it regulates mental activity when there is need to resolve among competing representations. In this light, a recent proposal hypothesizes that this broad ‘cognitive control’ function of Broca’s area similarly serves language processing: Broca’s area is responsible for biasing production and comprehension processes when there are strong demands to resolve competition among incompatible characterizations of linguistic stimuli. Some questions that have been asked within this framework are as follows: Does Broca’s area help speakers produce an appropriate word when many alternatives are equally plausible? Does it permit readers and listeners to successfully understand words and sentences, even when the input is ripe for misinterpretation? In the current article, we review new empirical evidence from various fields that supports such an account. A central piece to this discussion is how careful scrutiny of language performance, under varying degrees of cognitive control demands, may shed light on how to suitably describe the idiosyncratic language traits of patients with focal Broca’s area damage, who are decidedly not agrammatic. When explaining how he drives home every weekend, Patient A says: