Craig G. Chambers

Accent and reference resolution in spoken-language comprehension

Abstract The role of accent in reference resolution was investigated by monitoring eye fixations to lexical competitors (e.g., candy and candle ) as participants followed prerecorded instructions to move objects above or below fixed geometric shapes using a computer mouse. In Experiment 1, the first utterance instructed participants to move one object above or below a shape (e.g., “Put the candle/candy below the triangle”) and the second utterance contained an accented or deaccented definite noun phrase which referred to the same object or introduced a new entity (e.g., “Now put the CANDLE above the square” vs. “Now put the candle ABOVE THE SQUARE”). Fixations to the competitor (e.g., candy ) demonstrated a bias to interpret deaccented nouns as anaphoric and accented nouns as nonanaphoric. Experiment 2 used only accented nouns in the second instruction, varying whether the referent of this second instruction was the Theme of the first instruction (e.g., “Put the candle below the triangle”) or the Goal of the first instruction (e.g., “Put the necklace below the candle”). Participants preferred to interpret accented noun phrases as referring to a previously mentioned nonfocused entity (the Goal) rather than as introducing a new unmentioned entity.

Eye movements and lexical access in spoken-language comprehension: evaluating a linking hypothesis between fixations and linguistic processing.

A growing number of researchers in the sentence processing community are using eye movements to address issues in spoken language comprehension. Experiments using this paradigm have shown that visually presented referential information, including properties of referents relevant to specific actions, influences even the earliest moments of syntactic processing. Methodological concerns about task-specific strategies and the linking hypothesis between eye movements and linguistic processing are identified and discussed. These concerns are addressed in a review of recent studies of spoken word recognition which introduce and evaluate a detailed linking hypothesis between eye movements and lexical access. The results provide evidence about the time course of lexical activation that resolves some important theoretical issues in spoken-word recognition. They also demonstrate that fixations are sensitive to properties of the normal language-processing system that cannot be attributed to task-specific strategies.

Preschoolers’ sensitivity to referential ambiguity: evidence for a dissociation between implicit understanding and explicit behavior

Four-year-olds were asked to assess an adult listeners knowledge of the location of a hidden sticker after the listener was provided an ambiguous or unambiguous description of the sticker location. When preschoolers possessed private knowledge about the sticker location, the location they chose indicated that they judged a description to be unambiguous even when the message was ambiguous from the listeners perspective. However, measures of implicit awareness (response latencies and eye movement measures) demonstrated that even when preschoolers had private knowledge about the sticker location, ambiguous messages led to more consideration of an alternative location and longer response latencies than unambiguous messages. The findings demonstrate that children show sensitivity to linguistic ambiguity earlier than previously thought and, further, that they can detect linguistic ambiguity in language directed to others even when their own knowledge clarifies the intended meaning.

Perception and presupposition in real-time language comprehension: insights from anticipatory processing.

Recent studies have shown that listeners use verbs and other predicate terms to anticipate reference to semantic entities during real-time language comprehension. This process involves evaluating the denoted action against relevant properties of potential referents. The current study explored whether action-relevant properties are readily available to comprehension systems as a result of the embodied nature of linguistic and conceptual representations. In three experiments, eye movements were monitored as listeners followed instructions to move depicted objects on a computer screen. Critical instructions contained the verb return (e.g., Now return the block to area 3), which presupposes the previous displacement of its complement object--a property that is not reflected in perceptible or stable characteristics of objects. Experiment 1 demonstrated that predictions for previously displaced objects are generated upon hearing return, ruling out the possibility that anticipatory effects draw directly on static affordances in perceptual symbols. Experiment 2 used a referential communication task to evaluate how communicative relevance constrains the use of perceptually derived information. Results showed that listeners anticipate previously displaced objects as candidates upon hearing return only when their displacement was known to the speaker. Experiment 3 showed that the outcome of the original act of displacement further modulates referential predictions. The results show that the use of perceptually grounded information in language interpretation is subject to communicative constraints, even when language denotes physical actions performed on concrete objects.

Generic Language and Speaker Confidence Guide Preschoolers' Inferences About Novel Animate Kinds

We investigated the influence of speaker certainty on 156 four-year-old childrens sensitivity to generic and nongeneric statements. An inductive inference task was implemented, in which a speaker described a nonobvious property of a novel creature using either a generic or a nongeneric statement. The speaker appeared to be confident, neutral, or uncertain about the information being relayed. Preschoolers were subsequently asked if a second exemplar shared the same property as the first. Preschoolers consistently extended properties to additional exemplars only when properties were described in a generic form by a confident or neutral speaker. If a speaker appeared to be uncertain or if statements were made in a nongeneric form, properties were not consistently extended beyond the first exemplar. The findings demonstrate that children integrate the inductive cues provided by generic language with social cues when reasoning about abstract kinds.

Younger and Older Adults' Use of Verb Aspect and World Knowledge in the Online Interpretation of Discourse

Eye tracking was used to explore the role of grammatical aspect and world knowledge in establishing temporal relationships across sentences in discourse. Younger and older adult participants read short passages that included sentences such as Mrs. Adams was knitting/knitted a new sweater… She wore her new garment…. Readers had greater difficulty processing the second event (She wore...) if it followed the imperfective (was knitting) rather than the perfective (knitted) version of the earlier-mentioned event. This suggests that aspect information is encoded online and that the “in progress” interpretation of the imperfective impeded integration of the second event into the discourse model. However, world knowledge modulated the effect: When the first event was of short duration (e.g., writing a check), the influence of aspect was not evident in the early moments of processing. These effects were independent of age group, suggesting that the mechanisms involved in coordinating temporal information in discourse are stable across the adult lifespan.

Preschoolers’ sensitivity to speaker action constraints to infer referential intent

We investigated how preschoolers use their understanding of the actions available to a speaker to resolve referential ambiguity. In this study, 58 3- and 4-year-olds were presented with arrays of eight objects in a toy house and were instructed to retrieve various objects from the display. The trials varied in terms of whether the speakers hands were empty or full when she requested an object as well as whether the request was ambiguous (i.e., more than one potential referent) or unambiguous (i.e., only one potential referent). Results demonstrated that both 3- and 4-year-olds were sensitive to speaker action constraints and used this information to guide on-line processing (as indexed by eye gaze measures) and to make explicit referential decisions.

Mapping language to visual referents: Does the degree of image realism matter?

Studies of real-time spoken language comprehension have shown that listeners rapidly map unfolding speech to available referents in the immediate visual environment. This has been explored using various kinds of 2-dimensional (2D) stimuli, with convenience or availability typically motivating the choice of a particular image type. However, work in other areas has suggested that certain cognitive processes are sensitive to the level of realism in 2D representations. The present study examined the process of mapping language to depictions of objects that are more or less realistic, namely photographs versus clipart images. A custom stimulus set was first created by generating clipart images directly from photographs of real objects. Two visual world experiments were then conducted, varying whether referent identification was driven by noun or verb information. A modest benefit for clipart stimuli was observed during real-time processing, but only for noun-driving mappings. The results are discussed in terms of their implications for studies of visually situated language processing.

Five-Year-Olds’ and Adults’ Use of Paralinguistic Cues to Overcome Referential Uncertainty

An eye-tracking methodology was used to explore adults’ and children’s use of two utterance-based cues to overcome referential uncertainty in real time. Participants were first introduced to two characters with distinct color preferences. These characters then produced fluent (“Look! Look at the blicket.”) or disfluent (“Look! Look at thee, uh, blicket.”) instructions referring to novel objects in a display containing both talker-preferred and talker-dispreferred colored items. Adults (Expt 1, n = 24) directed a greater proportion of looks to talker-preferred objects during the initial portion of the utterance (“Look! Look at…”), reflecting the use of indexical cues for talker identity. However, they immediately reduced consideration of an object bearing the talker’s preferred color when the talker was disfluent, suggesting they infer disfluency would be more likely as a talker describes dispreferred objects. Like adults, 5-year-olds (Expt 2, n = 27) directed more attention to talker-preferred objects during the initial portion of the utterance. Children’s initial predictions, however, were not modulated when disfluency was encountered. Together, these results demonstrate that adults, but not 5-year-olds, can act on information from two talker-produced cues within an utterance, talker preference, and speech disfluencies, to establish reference.

Picture perfect: A stimulus set of 225 pairs of matched clipart and photographic images normed by Mechanical Turk and laboratory participants

The present study provides normative measures for a new stimulus set of images consisting of 225 everyday objects, each depicted both as a photograph and a matched clipart image generated directly from the photograph (450 images total). The clipart images preserve the same scale, shape, orientation, and general color features as the corresponding photographs. Various norms (modal name and verb agreement measures, picture–name agreement, familiarity, visual complexity, and image agreement) were collected separately for each image type and in two different contexts: online (using Mechanical Turk) and in the laboratory. We discuss similarities and differences in the normative measures according to both image type and experimental context. The full set of norms is provided in the supplemental materials.