Publications

• https://www.mpi.nl/publications/item3310165/referential-entropy-influences-production-overspecifications

@miscellaneous{Tourtourietal2018b,
title = {Referential entropy influences the production of overspecifications},
author = {Elli Tourtouri and Les Sikos and Matthew W. Crocker},
url = {https://www.mpi.nl/publications/item3310165/referential-entropy-influences-production-overspecifications},
year = {2018},
date = {2018},
booktitle = {10th Dubrovnik Conference on Cognitive Science, Communication, Pragmatics, and Theory of Mind (DuCog)},
publisher = {University of Zagreb},
address = {Dubrovnik, Croatia},
pubstate = {published},
type = {miscellaneous}
}

Copy BibTeX to Clipboard

In situated communication, reference can be established with expressions conveying either precise (Minimally-Specified, MS) or redundant (Over-Specified, OS) information. For example, while in Figure 1, “Find the blue ball” identifies exactly one object in all panels, only in the top displays is the adjective required. There is no consensus, however, concerning whether OS hinders processing (e.g., Engelhardt et al., 2011) or not (e.g., Tourtouri et al., 2015). Additionally, as incoming words incrementally restrict the referential domain, they contribute to the reduction of uncertainty regarding the target (i.e., referential entropy). Depending on the distribution of objects, the same utterance results in different entropy reduction profiles: “blue” reduces entropy by 1.58 bits in the right panels, and by .58 bits in the left ones, while “ball” reduces entropy by 1 and 2 bits, respectively. Thus, the adjective modulates the distribution of entropy reduction, resulting in uniform (UR) or non-uniform (NR) reduction profiles. This study seeks to establish whether referential processing is facilitated: a) by the use of redundant pre-nominal modification (OS), b) by the uniform reduction of entropy (cf. Jaeger, 2010), and c) when these two factors interact. Results from inspection probabilities and the Index of Cognitive Activity — a pupillometric measure of cognitive workload (Demberg & Sayeed, 2016) — indicate that processing was facilitated for both OS and UR, while fixation probabilities show a greater advantage for OS-UR. In conclusion, efficient processing is determined by both informativity of the reference and the rate of entropy reduction.

• https://www.researchgate.net/publication/322556329_The_interplay_of_specificity_and_referential_entropy_reduction_in_situated_communication

@inproceedings{Tourtourietal2017d,
title = {The interplay of specificity and referential entropy reduction in situated communication},
author = {Elli Tourtouri and Francesca Delogu and Matthew W. Crocker},
url = {https://www.researchgate.net/publication/322556329_The_interplay_of_specificity_and_referential_entropy_reduction_in_situated_communication},
year = {2017},
date = {2017},
booktitle = {10th Annual Embodied and Situated Language (ESLP) Conference},
publisher = {Higher School of Economics},
address = {Moscow, Russia},
abstract = {In situated communication, reference can be established with expressions conveying either precise (Minimally-Specified, MS) or redundant (Over-Specified, OS) information. For example, while in Figure 1, “Find the blue ball” identifies exactly one object in all panels, only in the top displays is the adjective required. There is no consensus, however, concerning whether OS hinders processing (e.g., Engelhardt et al., 2011) or not (e.g., Tourtouri et al., 2015). Additionally, as incoming words incrementally restrict the referential domain, they contribute to the reduction of uncertainty regarding the target (i.e., referential entropy). Depending on the distribution of objects, the same utterance results in different entropy reduction profiles: “blue” reduces entropy by 1.58 bits in the right panels, and by .58 bits in the left ones, while “ball” reduces entropy by 1 and 2 bits, respectively. Thus, the adjective modulates the distribution of entropy reduction, resulting in uniform (UR) or non-uniform (NR) reduction profiles. This study seeks to establish whether referential processing is facilitated: a) by the use of redundant pre-nominal modification (OS), b) by the uniform reduction of entropy (cf. Jaeger, 2010), and c) when these two factors interact. Results from inspection probabilities and the Index of Cognitive Activity — a pupillometric measure of cognitive workload (Demberg & Sayeed, 2016) — indicate that processing was facilitated for both OS and UR, while fixation probabilities show a greater advantage for OS-UR. In conclusion, efficient processing is determined by both informativity of the reference and the rate of entropy reduction.},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

Over-specifications (OS) are expressions that provide more information than minimally required for the identification of a referent, thereby violating Grice’s 2nd Quantity Maxim [1]. In Figure 1, for example, the expression “Find the blue ball” identifies exactly one object in all panels, but only in the top displays is the adjective required to disambiguate the target. In recent years, psycholinguistic research has tried to test the empirical validity of Grice’s Maxim, resulting in conflicting findings. That is, there is evidence both that OS hinders [2,3] and that it facilitates [4,5] referential processing. The current study investigates the influence of OS on visually-situated processing, when the context allows both a minimally-specified (MS) and an OS interpretation of pre-nominal adjectives (cf. Fig.1). Additionally, as the utterance unfolds over time, incoming words incrementally restrict the search space. In this sense, information on “blue” and “ball” is determined not only by their probability to occur in this context, but also by the amount of uncertainty about the target they reduce — in information theoretic terms [6]. A greater reduction of the referential set size on the adjective (A&C) results in a more uniform reduction profile (Uniform Reduction, UR), as the adjective reduces entropy by 1.58 bits and the noun by 1 bit. On the other hand, a moderate reduction of the set size on the adjective (B&D) results in a less uniform reduction profile (Nonuniform Reduction, NR): the adjective reduces entropy by .58 bits and the noun by 2 bits. This study examines whether, above and beyond any effects of specificity, the rate at which incoming words reduce visual entropy also affects referential processing.

• TourtouriDeloguCrocker     (0.54MB)
• https://www.researchgate.net/publication/322571202_Over-specification_Uniform_Reduction_of_Visual_Entropy_Facilitate_Referential_Processing

@inproceedings{Tourtourietal2017b,
title = {Overspecification and uniform reduction of visual entropy facilitate referential processing},
author = {Elli Tourtouri and Francesca Delogu and Matthew W. Crocker},
url = {https://www.researchgate.net/publication/322571202_Over-specification_Uniform_Reduction_of_Visual_Entropy_Facilitate_Referential_Processing},
year = {2017},
date = {2017},
booktitle = {XPrag2017},
address = {Cologne, Germany},
abstract = {Over-specifications (OS) are expressions that provide more information than minimally required for the identification of a referent, thereby violating Grice’s 2nd Quantity Maxim [1]. In Figure 1, for example, the expression “Find the blue ball” identifies exactly one object in all panels, but only in the top displays is the adjective required to disambiguate the target. In recent years, psycholinguistic research has tried to test the empirical validity of Grice’s Maxim, resulting in conflicting findings. That is, there is evidence both that OS hinders [2,3] and that it facilitates [4,5] referential processing. The current study investigates the influence of OS on visually-situated processing, when the context allows both a minimally-specified (MS) and an OS interpretation of pre-nominal adjectives (cf. Fig.1). Additionally, as the utterance unfolds over time, incoming words incrementally restrict the search space. In this sense, information on “blue” and “ball” is determined not only by their probability to occur in this context, but also by the amount of uncertainty about the target they reduce — in information theoretic terms [6]. A greater reduction of the referential set size on the adjective (A&C) results in a more uniform reduction profile (Uniform Reduction, UR), as the adjective reduces entropy by 1.58 bits and the noun by 1 bit. On the other hand, a moderate reduction of the set size on the adjective (B&D) results in a less uniform reduction profile (Nonuniform Reduction, NR): the adjective reduces entropy by .58 bits and the noun by 2 bits. This study examines whether, above and beyond any effects of specificity, the rate at which incoming words reduce visual entropy also affects referential processing.},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

Behavioral studies demonstrate the influence of speaker gaze in visually-situated spoken language comprehension. We present an ERP experiment examining the influence of speaker’s gaze congruency on listeners’ comprehension of referential expressions related to a shared visual scene. We demonstrate that listeners exploit speakers’ gaze toward objects in order to form sentence continuation expectations: Compared to a congruent gaze condition, we observe an increased N400 when (a) the lack of gaze (neutral) does not allow for upcoming noun prediction, and (b) when the noun violates gaze-driven expectations (incongruent). The later also results in a late (sustained) positivity, reflecting the need to update the assumed situation model. We take the combination of the N400 and late positivity as evidence that speaker gaze influences both lexical retrieval and integration processes, respectively (Brouwer et al., in press). Moreover, speaker gaze is interpreted as reflecting referential intentions (Staudte & Crocker, 2011).

• CogSci2017     (0.24MB)
• https://www.researchgate.net/publication/325969989_The_Influence_of_Speaker%27s_Gaze_on_Sentence_Comprehension_An_ERP_Investigation

@inproceedings{Jachmann2017,
title = {The Influence of Speaker's Gaze on Sentence Comprehension: An ERP Investigation},
author = {Torsten Jachmann and Heiner Drenhaus and Maria Staudte and Matthew W. Crocker},
url = {https://www.researchgate.net/publication/325969989_The_Influence_of_Speaker%27s_Gaze_on_Sentence_Comprehension_An_ERP_Investigation},
year = {2017},
date = {2017},
booktitle = {Proceedings of the 39th Annual Conference of the Cognitive Science Society},
pages = {2261-2266},
abstract = {Behavioral studies demonstrate the influence of speaker gaze in visually-situated spoken language comprehension. We present an ERP experiment examining the influence of speaker’s gaze congruency on listeners’ comprehension of referential expressions related to a shared visual scene. We demonstrate that listeners exploit speakers’ gaze toward objects in order to form sentence continuation expectations: Compared to a congruent gaze condition, we observe an increased N400 when (a) the lack of gaze (neutral) does not allow for upcoming noun prediction, and (b) when the noun violates gaze-driven expectations (incongruent). The later also results in a late (sustained) positivity, reflecting the need to update the assumed situation model. We take the combination of the N400 and late positivity as evidence that speaker gaze influences both lexical retrieval and integration processes, respectively (Brouwer et al., in press). Moreover, speaker gaze is interpreted as reflecting referential intentions (Staudte & Crocker, 2011).},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

In situated communication, reference to an entity in the shared visual context can be established using eitheranexpression that conveys precise (minimally specified) or redundant (over-specified) information. There is, however, along-lasting debate in psycholinguistics concerningwhether the latter hinders referential processing. We present evidence from an eyetrackingexperiment recordingfixations as well asthe Index of Cognitive Activity –a novel measure of cognitive workload –supporting the view that over-specifications facilitate processing. We further present originalevidence that, above and beyond the effect of specificity,referring expressions thatuniformly reduce referential entropyalso benefitprocessing

• Tourtouri, Delogu, Crocker - 2017 - Specificity and Entropy Reduction in situated referential processing     (2.47MB)
• https://www.mpi.nl/publications/item3309545/specificity-and-entropy-reduction-situated-referential-processing

@inproceedings{Tourtouri2017,
title = {Specificity and entropy reduction in situated referential processing},
author = {Elli Tourtouri and Francesca Delogu and Matthew W. Crocker},
url = {https://www.mpi.nl/publications/item3309545/specificity-and-entropy-reduction-situated-referential-processing},
year = {2017},
date = {2017},
booktitle = {39th Annual Conference of the Cognitive Science Society},
address = {Austin, Texas, USA},
abstract = {In situated communication, reference to an entity in the shared visual context can be established using eitheranexpression that conveys precise (minimally specified) or redundant (over-specified) information. There is, however, along-lasting debate in psycholinguistics concerningwhether the latter hinders referential processing. We present evidence from an eyetrackingexperiment recordingfixations as well asthe Index of Cognitive Activity –a novel measure of cognitive workload –supporting the view that over-specifications facilitate processing. We further present originalevidence that, above and beyond the effect of specificity,referring expressions thatuniformly reduce referential entropyalso benefitprocessing},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

The Uniform Information Density (UID) hypothesis links production strategies with comprehension processes, predicting that speakers will utilize flexibility in encoding in order to increase uniformity in the rate of information transmission, as measured by surprisal (Jaeger, 2010). Evidence in support of UID comes primarily from studies focusing on word-level effects, e.g. demonstrating that surprisal predicts the omission/inclusion of optional words. Here we investigate whether comprehenders are sensitive to the information density of alternative encodings that are more syntactically complex. We manipulated the syntactic encoding of complex noun phrases in German via meaning-preserving pre-nominal and post-nominal modification in contexts that were either predictive or non-predictive. We then used the G-maze reading task to measure online comprehension during self-paced reading. The results are consistent with the UID hypothesis. Length-adjusted reading times were facilitated for pre-nominally modified head nouns, and this effect was larger in non-predictive contexts.

• https://www.semanticscholar.org/paper/Information-density-of-encodings%3A-The-role-of-in-Sikos-Greenberg/06a47324b53bc53e0e4762fd1547091d8b2392f1

@inproceedings{Sikos2017,
title = {Information density of encodings: The role of syntactic variation in comprehension},
author = {Les Sikos and Clayton Greenberg and Heiner Drenhaus and Matthew W. Crocker},
url = {https://www.semanticscholar.org/paper/Information-density-of-encodings%3A-The-role-of-in-Sikos-Greenberg/06a47324b53bc53e0e4762fd1547091d8b2392f1},
year = {2017},
date = {2017},
booktitle = {Proceedings of the 39th Annual Conference of the Cognitive Science Society(CogSci 2017)},
pages = {3168-3173},
address = {Austin, Texas, USA},
abstract = {The Uniform Information Density (UID) hypothesis links production strategies with comprehension processes, predicting that speakers will utilize flexibility in encoding in order to increase uniformity in the rate of information transmission, as measured by surprisal (Jaeger, 2010). Evidence in support of UID comes primarily from studies focusing on word-level effects, e.g. demonstrating that surprisal predicts the omission/inclusion of optional words. Here we investigate whether comprehenders are sensitive to the information density of alternative encodings that are more syntactically complex. We manipulated the syntactic encoding of complex noun phrases in German via meaning-preserving pre-nominal and post-nominal modification in contexts that were either predictive or non-predictive. We then used the G-maze reading task to measure online comprehension during self-paced reading. The results are consistent with the UID hypothesis. Length-adjusted reading times were facilitated for pre-nominally modified head nouns, and this effect was larger in non-predictive contexts.},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

A model of sentence production is presented, which implements a strategy that produces sentences with more uniform surprisal profiles, as compared to other strategies, and in accordance to the Uniform Information Density Hypothesis (Jaeger, 2006; Levy & Jaeger, 2007). The model operates at the algorithmic level combining information concerning word probabilities and sentence lengths, representing a first attempt to model UID as resulting from underlying factors during language production. The sentences produced by this model showed indeed the expected tendency, having more uniform surprisal profiles and lower average word surprisal, in comparison to other production strategies.

• https://cogsci.mindmodeling.org/2017/papers/0333/paper0333.pdf

@inproceedings{Calvillo2017,
title = {Fast and Easy: Approximating uniform information density in language production},
author = {Jesús Calvillo},
url = {https://cogsci.mindmodeling.org/2017/papers/0333/paper0333.pdf},
year = {2017},
date = {2017},
publisher = {39th Annual Conference of the Cognitive Science Society},
address = {Austin, Texas, USA},
abstract = {A model of sentence production is presented, which implements a strategy that produces sentences with more uniform surprisal profiles, as compared to other strategies, and in accordance to the Uniform Information Density Hypothesis (Jaeger, 2006; Levy & Jaeger, 2007). The model operates at the algorithmic level combining information concerning word probabilities and sentence lengths, representing a first attempt to model UID as resulting from underlying factors during language production. The sentences produced by this model showed indeed the expected tendency, having more uniform surprisal profiles and lower average word surprisal, in comparison to other production strategies.},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

@inproceedings{Tourtourietal2017a,
title = {Overspecifications efficiently manage referential entropy in situated communication},
author = {Elli Tourtouri and Francesca Delogu and Matthew W. Crocker},
year = {2017},
date = {2017},
booktitle = {Paper presented at the 39th Annual Conference of the German Linguistic Society (DGfS)},
publisher = {Saarland University},
address = {Saarbruecken, Germany},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

A novel connectionist model of sentence production is presented, which employs rich situation model representations originally proposed for modeling systematicity in comprehension (Frank, Haselager, & van Rooij, 2009). The high overall performance of our model demonstrates that such representations are not only suitable for comprehension, but also for modeling language production. Further, the model is able to produce novel encodings (active vs. passive) for a particular semantics, as well as generate such encodings for previously unseen situations, thus demonstrating both syntactic and semantic systematicity. Our results provide yet further evidence that such connectionist approaches can achieve systematicity, in production as well as comprehension.

• Calvillo2016ConnectionistSemantic     (0.18MB)
• https://www.researchgate.net/publication/306400823_Connectionist_Semantic_Systematicity_in_Language_Production

@inproceedings{Calvillo2016,
title = {Connectionist semantic systematicity in language production},
author = {Jesús Calvillo and Harm Brouwer and Matthew W. Crocker},
url = {https://www.researchgate.net/publication/306400823_Connectionist_Semantic_Systematicity_in_Language_Production},
year = {2016},
date = {2016},
publisher = {38th Annual Conference of the Cognitive Science Society},
address = {Austin, Texas, USA},
abstract = {A novel connectionist model of sentence production is presented, which employs rich situation model representations originally proposed for modeling systematicity in comprehension (Frank, Haselager, & van Rooij, 2009). The high overall performance of our model demonstrates that such representations are not only suitable for comprehension, but also for modeling language production. Further, the model is able to produce novel encodings (active vs. passive) for a particular semantics, as well as generate such encodings for previously unseen situations, thus demonstrating both syntactic and semantic systematicity. Our results provide yet further evidence that such connectionist approaches can achieve systematicity, in production as well as comprehension.},
pubstate = {published},
type = {inproceedings}
}

Copy BibTeX to Clipboard

Violations of the maxims of Quantity occur when utterances provide more (over-specified) or less (under-specified) information than strictly required for referent identification. While behavioural data suggest that under-specified expressions lead to comprehension difficulty and communicative failure, there is no consensus as to whether over-specified expressions are also detrimental to comprehension. In this study we shed light on this debate, providing neurophysiological evidence supporting the view that extra information facilitates comprehension. We further present novel evidence that referential failure due to underspecification is qualitatively different from explicit cases of referential failure, when no matching referential candidate is available in the context.

• https://www.researchgate.net/publication/312296322_ERP_indices_of_situated_reference_in_visual_contexts

@article{Tourtouri2015,
title = {ERP Indices of situated reference in visual contexts},
author = {Elli Tourtouri and Francesca Delogu and Matthew W. Crocker},
url = {https://www.researchgate.net/publication/312296322_ERP_indices_of_situated_reference_in_visual_contexts},
year = {2015},
date = {2015},
publisher = {37th Annual Conference of the Cognitive Science Society},
address = {Austin, Texas, USA},
abstract = {Violations of the maxims of Quantity occur when utterances provide more (over-specified) or less (under-specified) information than strictly required for referent identification. While behavioural data suggest that under-specified expressions lead to comprehension difficulty and communicative failure, there is no consensus as to whether over-specified expressions are also detrimental to comprehension. In this study we shed light on this debate, providing neurophysiological evidence supporting the view that extra information facilitates comprehension. We further present novel evidence that referential failure due to underspecification is qualitatively different from explicit cases of referential failure, when no matching referential candidate is available in the context.},
pubstate = {published},
type = {article}
}

Copy BibTeX to Clipboard

• https://www.researchgate.net/publication/322570166_ERP_indices_of_referential_informativity_in_visual_contexts

@inproceedings{Tourtourietal2015a,
title = {ERP indices of referential informativity in visual contexts},
author = {Elli Tourtouri and Francesca Delogu and Matthew W. Crocker},
url = {https://www.researchgate.net/publication/322570166_ERP_indices_of_referential_informativity_in_visual_contexts},
year = {2015},
date = {2015},
booktitle = {Paper presented at the 28th CUNY Conference on Human Sentence Processing},
publisher = {University of South California},
address = {Los Angeles, USA},
abstract = {

Copy BibTeX to Clipboard