Semantic Ambiguity and Perceived Ambiguity

I explore some of the issues that arise when trying to establish a connection between the underspecification hypothesis pursued in the NLP literature and work on ambiguity in semantics and in the psychological literature. A theory of underspecification is developed `from the first principles', i.e., starting from a definition of what it means for a sentence to be semantically ambiguous and from what we know about the way humans deal with ambiguity. An underspecified language is specified as the translation language of a grammar covering sentences that display three classes of semantic ambiguity: lexical ambiguity, scopal ambiguity, and referential ambiguity. The expressions of this language denote sets of senses. A formalization of defeasible reasoning with underspecified representations is presented, based on Default Logic. Some issues to be confronted by such a formalization are discussed.Comment: Latex, 47 pages. Uses tree-dvips.sty, lingmacros.sty, fullname.st

Representation and processing of semantic ambiguity

One of the established findings in the psycholinguistic literature is that semantic ambiguity (e.g., “dog/tree bark”) slows word comprehension in neutral/ minimal context, though it is not entirely clear why this happens. Under the “semantic competition” account, this ambiguity disadvantage effect is due to competition between multiple semantic representations in the race for activation. Under the alternative “decision-making” account, it is due to decision-making difficulties in response selection. This thesis tests the two accounts by investigating in detail the ambiguity disadvantage in semantic relatedness decisions. Chapters 2-4 concentrate on homonyms, words with multiple unrelated meanings. The findings show that the ambiguity disadvantage effect arises only when the different meanings of homonyms are of comparable frequency (e.g., “football/electric fan”), and are therefore initially activated in parallel. Critically, homonymy has this effect during semantic activation of the ambiguous word, not during response selection. This finding, in particular, refutes any idea that the ambiguity disadvantage is due to decision making in response selection. Chapters 5 and 6 concentrate on polysemes, words with multiple related senses. The findings show that the ambiguity disadvantage effect arises for polysemes with irregular sense extension (e.g., “restaurant/website menu”), but not for polysemes with regular (e.g., “fluffy/marinated rabbit”) or figurative sense extension (e.g., “wooden/authoritative chair”). The latter two escape competition because they have only one semantic representation for the dominant sense, with rules of sense extension to derive the alternative sense on-line. Taken together, this thesis establishes that the ambiguity disadvantage is due to semantic competition but is restricted to some forms of ambiguity only. This is because ambiguous words differ in how their meanings are represented and processed, as delineated in this work

Characterizing Semantic Ambiguity of the Materials Science Ontologies

Growth in computational materials science and initiatives such as the Materials Genome Initiative (MGI) and the European Materials Modelling Council (EMMC) has motivated the development and application of ontologies. A key factor has been increased adoption of the FAIR principles, making research data findable, accessible, interoperable, and reusable (Wilkinson et al. 2016). This paper characterizes semantic interoperability among a subset of materials science ontologies in the MatPortal repository. Background context covers semantic interoperability, ontological commitment, and the materials science ontology landscape. The research focused on MatPortal's two interoperability protocols: LOOM term matching and URI matching. Results report the degree of overlap and demonstrate the different types of ambiguity among ontologies. The discussion considers implications for FAIR and AI, and the conclusion highlight key findings and next steps.Comment: 12 pages, International Society for Knowledge Organization (ISKO) 202

Logical relations for coherence of effect subtyping

A coercion semantics of a programming language with subtyping is typically defined on typing derivations rather than on typing judgments. To avoid semantic ambiguity, such a semantics is expected to be coherent, i.e., independent of the typing derivation for a given typing judgment. In this article we present heterogeneous, biorthogonal, step-indexed logical relations for establishing the coherence of coercion semantics of programming languages with subtyping. To illustrate the effectiveness of the proof method, we develop a proof of coherence of a type-directed, selective CPS translation from a typed call-by-value lambda calculus with delimited continuations and control-effect subtyping. The article is accompanied by a Coq formalization that relies on a novel shallow embedding of a logic for reasoning about step-indexing

Using Semantic Ambiguity Instruction to Improve Third Graders\u27 Metalinguistic Awareness and Reading Comprehension: An Experimental Study

An experiment examined whether metalinguistic awareness involving the detection of semantic ambiguity can be taught and whether this instruction improves students\u27 reading comprehension. Lower socioeconomic status third graders (M age = 8 years, 7 months) from a variety of cultural backgrounds (N = 46) were randomly assigned to treatment and control groups. Those receiving metalinguistic ambiguity instruction learned to analyze multiple meanings of words and sentences in isolation, in riddles, and in text taken from the Amelia Bedelia series (Parish, 1979, 988). The control group received a book-reading and discussion treatment to provide special attention and to rule out Hawthorne effects. Results showed that metalinguistic ambiguity instruction was effective in teaching students to identify multiple meanings of homonyms and ambiguous sentences and to detect inconsistencies in text. Moreover, this training enhanced students\u27 reading com prehension on a paragraph-completion task but not on a multiple-choice passage-recall task, possibly because the two tests differ in the array of linguistic or cognitive correlates influencing performance. Comprehension monitoring was not found to mediate the relationship between ambiguity instruction and reading comprehension. Results carry implications for the use of language-based methods to improve reading comprehension in the classroom

Modeling Ambiguity in a Multi-Agent System

This paper investigates the formal pragmatics of ambiguous expressions by modeling ambiguity in a multi-agent system. Such a framework allows us to give a more refined notion of the kind of information that is conveyed by ambiguous expressions. We analyze how ambiguity affects the knowledge of the dialog participants and, especially, what they know about each other after an ambiguous sentence has been uttered. The agents communicate with each other by means of a TELL-function, whose application is constrained by an implementation of some of Grice's maxims. The information states of the multi-agent system itself are represented as a Kripke structures and TELL is an update function on those structures. This framework enables us to distinguish between the information conveyed by ambiguous sentences vs. the information conveyed by disjunctions, and between semantic ambiguity vs. perceived ambiguity.Comment: 7 page