Lexical acquisition in elementary science classes

The purpose of this study was to further researchers' understanding of lexical acquisition in the beginning primary schoolchild by investigating word learning in small-group elementary science classes. Two experiments were conducted to examine the role of semantic scaffolding (e.g., use of synonymous terms) and physical scaffolding (e.g., pointing to referents) in children's acquisition of novel property terms. Children's lexical knowledge was assessed using multiple tasks (naming, comprehension, and definitional). Children struggled to acquire meanings of adjectives without semantic or physical scaffolding (Experiment 1), but they were successful in acquiring extensive lexical knowledge when offered semantic scaffolding (Experiment 2). Experiment 2 also shows that semantic scaffolding used in combination with physical scaffolding helped children acquire novel adjectives and that children who correctly named pictures of adjectives had acquired definitions

Passives in first language acquisition: What causes the delay?

The passive construction is a late acquisition in child language. In this paper I evaluate the claim that difficulty with noncanonical semantics, rather than non-mature subject-object A-chains, underlie young children’s poor performance on the passive. In a series of truth-value judgment tasks, 4- and 5-year-old English-speaking children were tested on their comprehension of matrix passives and passives embedded under raising-to-object (RO: want, need) and object control (OC: ask, tell) verbs. RO passives (Olivia wanted/needed Scott to be kissed by Misha) entail object-subject-object A-chains, but allow semantic patients to surface as syntactic objects; OC passives (Olivia asked/told Scott to be kissed by Misha) and matrix passives (Scott was kissed by Misha) involve similar A-chains but do not result in this syntactic-semantic configuration. I found that although 4-year-olds failed to comprehend matrix passives and passives embedded under OC verbs, they correctly interpreted passives under RO verbs. (5-year-olds performed above chance in all tasks.) I propose a “semantic scaffolding” account of children’s comprehension of the passive that rests on the prototypicality of subjects being agents and objects being patients, arguing against the view that difficulty with passives results from an inability to form A-chains

Folks in Folksonomies: Social Link Prediction from Shared Metadata

Web 2.0 applications have attracted a considerable amount of attention because their open-ended nature allows users to create light-weight semantic scaffolding to organize and share content. To date, the interplay of the social and semantic components of social media has been only partially explored. Here we focus on Flickr and Last.fm, two social media systems in which we can relate the tagging activity of the users with an explicit representation of their social network. We show that a substantial level of local lexical and topical alignment is observable among users who lie close to each other in the social network. We introduce a null model that preserves user activity while removing local correlations, allowing us to disentangle the actual local alignment between users from statistical effects due to the assortative mixing of user activity and centrality in the social network. This analysis suggests that users with similar topical interests are more likely to be friends, and therefore semantic similarity measures among users based solely on their annotation metadata should be predictive of social links. We test this hypothesis on the Last.fm data set, confirming that the social network constructed from semantic similarity captures actual friendship more accurately than Last.fm's suggestions based on listening patterns.Comment: http://portal.acm.org/citation.cfm?doid=1718487.171852

Design Research and Domain Representation

While diverse theories about the nature of design research have been proposed, they are rarely considered in relation to one another across the broader disciplinary field. Discussions of design research paradigms have tended to use overarching binary models for understanding differing knowledge frameworks. This paper focuses on an analysis of theories of design research and the use of Web 3 and open content systems to explore the potential of building more relational modes of conceptual representation. The nature of this project is synthetic, building upon the work of other design theorists and researchers. A number of theoretical frameworks will be discussed and examples of the analysis and modelling of key concepts and information relationships, using concept mapping software, collaborative ontology building systems and semantic wiki technologies will be presented. The potential of building information structures from content relationships that are identified by domain specialists rather than the imposition of formal, top-down, information hierarchies developed by information scientists, will be considered. In particular the opportunity for users to engage with resources through their own knowledge frameworks, rather than through logically rigorous but largely incomprehensible ontological systems, will be explored in relation to building resources for emerging design researchers. The motivation behind this endeavour is not to create a totalising meta-theory or impose order on the ‘ill structured’ and ‘undisciplined’, domain of design. Nor is it to use machine intelligence to ‘solve design problems’. It seeks to create dynamic systems that might help researchers explore design research theories and their various relationships with one another. It is hoped such tools could help novice researchers to better locate their own projects, find reference material, identify knowledge gaps and make new linkages between bodies of knowledge by enabling forms of data-poesis - the freeing of data for different trajectories. Keywords: Design research; Design theory; Methodology; Knowledge systems; Semantic web technologies.</p

Do What You Know: "Semantic Scaffolding" in Biclausal Raising and Control

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Neural Substrates of Semantic Prospection – Evidence from the Dementias

The ability to envisage personally relevant events at a future time point represents an incredibly sophisticated cognitive endeavor and one that appears to be intimately linked to episodic memory integrity. Far less is known regarding the neurocognitive mechanisms underpinning the capacity to envisage non-personal future occurrences, known as semantic future thinking. Moreover the degree of overlap between the neural substrates supporting episodic and semantic forms of prospection remains unclear. To this end, we sought to investigate the capacity for episodic and semantic future thinking in Alzheimer’s disease (n = 15) and disease-matched behavioral-variant frontotemporal dementia (n = 15), neurodegenerative disorders characterized by significant medial temporal lobe (MTL) and frontal pathology. Participants completed an assessment of past and future thinking across personal (episodic) and non-personal (semantic) domains, as part of a larger neuropsychological battery investigating episodic and semantic processing, and their performance was contrasted with 20 age- and education-matched healthy older Controls. Participants underwent whole-brain T1-weighted structural imaging and voxel-based morphometry analysis was conducted to determine the relationship between gray matter integrity and episodic and semantic future thinking. Relative to Controls, both patient groups displayed marked future thinking impairments, extending across episodic and semantic domains. Analyses of covariance revealed that while episodic future thinking deficits could be explained solely in terms of episodic memory proficiency, semantic prospection deficits reflected the interplay between episodic and semantic processing. Distinct neural correlates emerged for each form of future simulation with differential involvement of prefrontal, lateral temporal, and medial temporal regions. Notably, the hippocampus was implicated irrespective of future thinking domain, with the suggestion of lateralization effects depending on the type of information being simulated. Whereas episodic future thinking related to right hippocampal integrity, semantic future thinking was found to relate to left hippocampal integrity. Our findings support previous observations of significant MTL involvement for semantic forms of prospection and point to distinct neurocognitive mechanisms which must be functional to support future-oriented forms of thought across personal and non-personal contexts

Friendship prediction and homophily in social media

International audienceSocial media have attracted considerable attention because their open-ended nature allows users to create lightweight semantic scaffolding to organize and share content. To date, the interplay of the social and topical components of social media has been only partially explored. Here, we study the presence of homophily in three systems that combine tagging social media with online social networks. We find a substantial level of topical similarity among users who are close to each other in the social network. We introduce a null model that preserves user activity while removing local correlations, allowing us to disentangle the actual local similarity between users from statistical effects due to the assortative mixing of user activity and centrality in the social network. This analysis suggests that users with similar interests are more likely to be friends, and therefore topical similarity measures among users based solely on their annotation metadata should be predictive of social links. We test this hypothesis on several datasets, confirming that social networks constructed from topical similarity capture actual friendship accurately. When combined with topological features, topical similarity achieves a link prediction accuracy of about 92%

Semantic scaffolding in first language acquisition: the acquisition of raising-to-object and object control

This dissertation joins the debates on whether language is innate and/or modular, by examining English-speaking children's acquisition of raising-to-object (RO; (1)) and object control (OC; (2)) utterances. 1. RO: Suki wanted/needed Neili [ti to kiss Louise] 2. OC: Suki asked/told Neili [PROi to kiss Louise] While these verbs may appear in the same surface string, they map onto two distinct underlying structures. As a result, they differ in their syntactic and semantic behaviors, including the interpretation of embedded passives, and whether the subject of the embedded clause may be expletive or inanimate. Several truth-value and sentence judgment tasks yielded the following results: Children have adultlike comprehension of active RO/OC utterances by age 4. Children who fail on tests of matrix passives can interpret passives embedded under RO verbs (despite their greater length and syntactic complexity), but not under OC verbs (which have syntax more like matrix passives). In sentence judgment tasks, children preferentially parse the embedded clause alone. To account for these patterns, I offder the semantic scaffolding hypothesis, which comprises two major proposals: (a) children assume a canonical alignment of thematic and grammatical roles, resulting in agent-subjects and patient-objects, and (b) children assume a default clausal shape of contiguous subject and predicate. I argue that children use semantic scaffolding as a stepping stone on their way to adultlike syntactic and processing power. In short, movement may be easier than control structures, if these assumptions are not violated. Moreover, the fact that children do maintain a distinction between the verb classes is evidence for innateness and modularity in language. However, the language module interacts crucially with other cognitive modules (e.g., the conceptual-semantic system) and with domain-general faculties (e.g., attention, memory). Finally, the results presented here also bear on the following issues: There is no evidence for maturation of A-chains and/or control, contra Wexler. Children's performance on active RO, passives, and embedded passives suggest that RO utterances should instead be analyzed as instances of exceptional case marking. The data can neither support nor refute Hornstein's proposal that RO and OC both be analyzed as instances of movement