We agree with Pickering & Garrod's (P&G's) proposal that dialogue is an important empirical and theoretical test bed for models of language processing. However, we offer two cautionary notes. First, the enterprise will require explicit computational models. Second, such models will need to incorporate both joint and separate speaker and hearer commitments in ways that go beyond priming and alignment.

Although the presence or absence of a pitch accent clearly can play an important role in signaling the discourse and information structure of an utterance, whether the form of an accent determines the type of information it conveys is more controversial. We used an eye‐tracking paradigm to investigate whether H*, which has been argued to signal new information, evokes different eye fixations than L+H*, which has been argued to signal the presence of contrast. Our results demonstrate that although listeners interpret (...) these accents differently, their interpretive domains overlap. L+H* creates a strong bias toward contrast referents whereas H* is compatible with both new and contrast referents. (shrink)

IntroductionCognitive impairment is a highly prevalent non-motor feature of Parkinson’s disease. A better understanding of the underlying pathophysiology may help in identifying therapeutic targets to prevent or treat dementia. This study sought to identify metabolic alterations in the prefrontal cortex, a key region for cognitive functioning that has been implicated in cognitive dysfunction in PD.MethodsProton Magnetic Resonance Spectroscopy was used to investigate metabolic changes in the PFC of a cohort of cognitively normal individuals without PD, as well as PD participants (...) with either normal cognition, mild cognitive impairment, or dementia. Ratios to Creatine resonance were obtained for glutamate, glutamine and glutamate combined, N-acetylaspartate, myoinositol, and total choline, and correlated with cognitive scores across multiple domains administered to the PD participants only.ResultsWhen individuals retain cognitive capabilities, the presence of Parkinson’s disease does not create metabolic disturbances in the PFC. However, when cognitive symptoms are present, PFC Glu/Cre ratios decrease with significant differences between the PD-NC and PPD groups. In addition, Glu/Cre ratios and memory scores were marginally associated, but not after Bonferroni correction.ConclusionThese preliminary findings indicate that fluctuations in prefrontal glutamate may constitute a biomarker for the progression of cognitive impairments in PD. We caution for larger MRS investigations of carefully defined PD groups. (shrink)

A classic problem in cognitive science concerns how listeners perceive and understand speech as comprised of discrete words. We propose a Syllable Inference account of spoken word recognition and segmentation, under which alternative hierarchical models of syllables, words, and phonemes are dynamically posited from cues that include current and past speech rate, with a goal of maximal prediction of sensory input. Three experiments using the Visual World eye‐tracking paradigm provide evidence supporting our proposal.

We propose, following Clark, that generative models also play a central role in the perception and interpretation of linguistic signals. The data explanation approach provides a rationale for the role of prediction in language processing and unifies a number of phenomena, including multiple-cue integration, adaptation effects, and cortical responses to violations of linguistic expectations.

During communication, we form assumptions about what our communication partners know and believe. Information that is mutually known between the discourse partners—their common ground—serves as a backdrop for successful communication. Here we present an introduction to the focus of this topic, which is the role of memory in common ground and language use. Two types of questions emerge as central to understanding the relationship between memory and common ground, specifically questions having to do with the representation of common ground in (...) memory, and the use of common ground during language processing. (shrink)

Three experiments investigated the processing of the implicature associated with some using a “gumball paradigm.” On each trial, participants saw an image of a gumball machine with an upper chamber with 13 gumballs and an empty lower chamber. Gumballs then dropped to the lower chamber and participants evaluated statements, such as “You got some of the gumballs.” Experiment 1 established that some is less natural for reference to small sets and unpartitioned sets compared to intermediate sets. Partitive some of was (...) less natural than simple some when used with the unpartitioned set. In Experiment 2, including exact number descriptions lowered naturalness ratings for some with small sets but not for intermediate size sets and the unpartitioned set. In Experiment 3, the naturalness ratings from Experiment 2 predicted response times. The results are interpreted as evidence for a Constraint-Based account of scalar implicature processing and against both two-stage, Literal-First models and pragmatic Default models. (shrink)

Two visual world experiments investigated the processing of the implicature associated with some using a “gumball paradigm.” On each trial, participants saw an image of a gumball machine with an upper chamber with orange and blue gumballs and an empty lower chamber. Gumballs dropped to the lower chamber, creating a contrast between a partitioned set of gumballs of one color and an unpartitioned set of the other. Participants then evaluated spoken statements, such as “You got some of the blue gumballs.” (...) Experiment 1 investigated the time course of the pragmatic enrichment from some to not all when the only utterance alternatives available to refer to the different sets were some and all. In Experiment 2, the number terms two, three, four, and five were also included in the set of alternatives. Scalar implicatures were delayed relative to the interpretation of literal statements with all only when number terms were available. The results are interpreted as evidence for a constraint-based account of scalar implicature processing. (shrink)

Since Horn (1972) the notion of conversational implicature proposed by Grice has been put to use to explain certain interpretive differences between expressions in natural language and their counterparts in formal logic. For example, the sentences in (1) seem to convey more than they would be expected to if the natural language disjunction or had the same meaning as the logical disjunction ∨, or if the quantificational determiner some was interpreted as the existential quantifier ∃.

Upon hearing a scalar adjective in a definite referring expression such as “the big…,” listeners typically make anticipatory eye movements to an item in a contrast set, such as a big glass in the context of a smaller glass. Recent studies have suggested that this rapid, contrastive interpretation of scalar adjectives is malleable and calibrated to the speaker's pragmatic competence. In a series of eye‐tracking experiments, we explore the nature of the evidence necessary for the modulation of pragmatic inferences in (...) language comprehension, focusing on the complementary roles of top–down information ‐ (knowledge about the particular speaker's pragmatic competence) and bottom‐up cues (distributional information about the use of scalar adjectives in the environment). We find that bottom‐up evidence alone (e.g., the speaker says “the big dog” in a context with one dog), in large quantities, can be sufficient to trigger modulation of the listener's contrastive inferences, with or without top‐down cues to support this adaptation. Further, these findings suggest that listeners track and flexibly combine multiple sources of information in service of efficient pragmatic communication. (shrink)

How do speakers design what they say in order to communicate effectively with groups of addressees who vary in their background knowledge of the topic at hand? Prior findings indicate that when a speaker addresses a pair of listeners with discrepant knowledge, that speakers Aim Low, designing their utterances for the least knowledgeable of the two addressees. Here, we test the hypothesis that speakers will depart from an Aim Low approach in order to efficiently communicate with larger groups of interacting (...) partners. Further, we ask whether the cognitive demands of tracking multiple conversational partners' perspectives places limitations on successful audience design. We find that speakers can successfully track information about what up to four of their partners do and do not know in conversation. When addressing groups of 3–4 addressees at once, speakers design language based on the combined knowledge of the group. These findings point to an audience design process that simultaneously represents the perspectives of multiple other individuals and combines these representations in order to design utterances that strike a balance between the different needs of the individuals within the group. (shrink)

Written memoranda of conversations, or memcons, provide a near‐contemporaneous record of what was said in conversation, and offer important insights into the activities of high‐profile individuals. We assess the impact of writing a memcon on memory for conversation. Pairs of participants engaged in conversation and were asked to recall the contents of that conversation 1 week later. One participant in each pair memorialized the content of the interaction in a memcon shortly after the conversation. Participants who generated memcons recalled more (...) details of the conversations than participants who did not, but the content of recall was equally and largely accurate for both participants. Remarkably, only 4.7% of the details of the conversation were recalled by both of the partners after a week delay. Contemporaneous note‐taking appears to enhance memory for conversation by increasing the amount of information remembered but not the accuracy of that information. These findings have implications for evaluating the testimony of participants on conversations with major political or legal ramifications. (shrink)

Communicating with multiple addressees poses a problem for speakers: Each addressee necessarily comes to the conversation with a different perspective—different knowledge, different beliefs, and a distinct physical context. Despite the ubiquity of multiparty conversation in everyday life, little is known about the processes by which speakers design language in multiparty conversation. While prior evidence demonstrates that speakers design utterances to accommodate addressee knowledge in multiparty conversation, it is unknown if and how speakers encode and combine different types of perspective information. (...) Here we test whether speakers encode the perspective of multiple addressees, and then simultaneously consider their knowledge and physical context during referential design in a three‐party conversation. Analyses of referential form—expression length, disfluency, and elaboration rate—in an interactive multiparty conversation demonstrate that speakers do take into consideration both addressee knowledge and physical context when designing utterances, consistent with a knowledge‐scene integration view. These findings point to an audience design process that takes as input multiple types of representations about the perspectives of multiple addressees, and that bases the informational content of the to‐be‐designed utterance on a combination of the perspectives of the intended addressees. (shrink)

Norris et al.'s claim that feedback is unnecessary is compromised by (1) a questionable application of Occam's razor, given strong evidence for feedback in perception; (2) an idealization of the speech recognition problem that simplifies those aspects of the input that create conditions where feedback is useful; (3) Norris et al.'s use of decision nodes that incorporate feedback to model some important empirical results; and (4) problematic linking hypotheses between crucial simulations and behavioral data.

We adopt the visual-world eye-tracking paradigm to test the hypothesis that scalar implicatures are integrated very locally to the utterance of scalar terms. Focusing on the and,or scale, we show that early point-of-disambiguation effects similar to those triggered by the integration of the lexical meaning of and can be triggered by the integration of the exhaustive meaning of or. Some design issues and an independent interpretive asymmetry holding between and and or are discussed as possible explanations for remaining differences between (...) the effects found in the two cases. We conclude that the exclusivity implicature that is associated to sentences containing or seems to be calculated online, rather locally to the utterance of the disjunction. (shrink)

In order to investigate whether addressees can make immediate use of speaker‐based constraints during reference resolution, participant addressees' eye movements were monitored as they helped a confederate cook follow a recipe. Objects were located in the helper's area, which the cook could not reach, and the cook's area, which both could reach. Critical referring expressions matched one object (helper's area) or two objects (helper's and cook's areas), and were produced when the cook's hands were empty or full, which defined the (...) cook's reaching ability constraints. Helper's first and total fixations showed that they restricted their domain of interpretation to their own objects when the cook's hands were empty, and widened it to include the cook's objects only when the cook's hands were full. These results demonstrate that addressees can quickly take into account task‐relevant constraints to restrict their referential domain to referents that are plausible given the speaker's goals and constraints. (shrink)

© 2017. The American Astronomical Society. All rights reserved.We present new observations of the low-mass companion to HD 984 taken with the Gemini Planet Imager as a part of the GPI Exoplanet Survey campaign. Images of HD 984 B were obtained in the J and H bands. Combined with archival epochs from 2012 and 2014, we fit the first orbit to the companion to find an 18 au orbit with a 68% confidence interval between 14 and 28 au, an eccentricity (...) of 0.18 with a 68% confidence interval between 0.05 and 0.47, and an inclination of 119°with a 68% confidence interval between 114°and 125°. To address the considerable spectral covariance in both spectra, we present a method of splitting the spectra into low and high frequencies to analyze the spectral structure at different spatial frequencies with the proper spectral noise correlation. Using the split spectra, we compare them to known spectral types using field brown dwarf and low-mass star spectra and find a best-fit match of a field gravity M6.5 ±1.5 spectral type with a corresponding temperature of K. Photometry of the companion yields a luminosity of log=2.88 ± 0.07 dex with DUSTY models. Mass estimates, again from DUSTY models, find an age-dependent mass of 34 ±1 to 95 ±4 M Jup. These results are consistent with previous measurements of the object. (shrink)

We agree with Pickering & Garrod's (P&G's) claim that theories of language processing must address the interconnection of language production and comprehension. However, we have two concerns: First, the central notion of context when predicting what another person will say is underspecified. Second, it is not clear that P&G's dual-mechanism model captures the data better than a single-mechanism model would.

Semantic memory encompasses one's knowledge about the world. Distributional semantic models, which construct vector spaces with embedded words, are a proposed framework for understanding the representational structure of human semantic knowledge. Unlike some classic semantic models, distributional semantic models lack a mechanism for specifying the properties of concepts, which raises questions regarding their utility for a general theory of semantic knowledge. Here, we develop a computational model of a binary semantic classification task, in which participants judged target words for the (...) referent's size or animacy. We created a family of models, evaluating multiple distributional semantic models, and mechanisms for performing the classification. The most successful model constructed two composite representations for each extreme of the decision axis (e.g., one averaging together representations of characteristically big things and another of characteristically small things). Next, the target item was compared to each composite representation, allowing the model to classify more than 1,500 words with human‐range performance and to predict response times. We propose that when making a decision on a binary semantic classification task, humans use task prompts to retrieve instances representative of the extremes on that semantic dimension and compare the probe to those instances. This proposal is consistent with the principles of the instance theory of semantic memory. (shrink)

Inspired by early proposals in philosophy, dominant accounts of language posit a central role for mutual knowledge, either encoded directly in common ground, or approximated through other cognitive mechanisms. Using existing empirical evidence from language and memory, we challenge this tradition, arguing that mutual knowledge captures only a subset of the mental states needed to support communication. In a novel theoretical proposal, we argue for a cognitive architecture that includes separate, distinct representations of the self and other, and a cognitive (...) process that compares these representations continuously during conversation, outputting both similarities and differences in perspective. Our theory accounts for existing data, interfaces with findings from other cognitive domains, and makes novel predictions about the role of perspective in language use. We term this new account the Multiple Perspectives Theory of mental states in communication. (shrink)