Visual Search and Target Selection Using a Bounded Optimal Model of State Estimation & Control

Visual attention and motor control are tightly coupled in domains requiring a human operator to interact with a visual interface. Here, we integrate a boundedly optimal visual attention model with two separate motor control models and compare the predictions made by these models against perceptual and motor data collected from human subjects engaged in a parafoveal detection task. The results indicate that humans use an optimal motor control policy limited by precision constraints – humans executed ballistic movements using near-optimal velocity (i.e., bang-bang control), but imprecision in those movements often caused participants to overshoot their targets, necessitating corrective action. Motor movements did not reflect response hedging, but rather a perceptual-motor policy permitting ballistic movements to a target only after localization confidence exceeded a threshold. We conclude that a boundedly-optimal perceptual-motor model can predict aspects of human performance visual search tasks requiring motor response

Epistemička modalnost u akademskom diskursu u hrvatskom i engleskom jeziku

The present thesis is the result of a cross-cultural, genre-based study whose main objective is to examine how writers of research articles in psychology in Croatian and English use epistemic modality devices in hedging their claims or in evaluating other scholars’ work. Based on the corpus of 60 research articles published in Croatian and English journals, the study aims to establish the patterns of similarities and differences in the use of the epistemic devices across the main rhetorical sections of a research article as well as to identify their major hedging functions. The overall results show that English writers use epistemic markers more frequently than their Croatian counterparts. This finding is generally in line with the previous cross-cultural studies, showing a more salient use of hedges and their more entrenched status in the Anglo- American writing as compared to academic writing in some other languages investigated. With respect to the individual categories of epistemic devices, the results show both similarities and differences in their uses across the two sub-corpora. In both the English and Croatian sub-corpus, epistemic modal verbs are employed most frequently, followed by epistemic verbs, while epistemic nouns are the least frequent category of epistemic devices. The major difference in the overall results concerns the distributional patterns in the use of epistemic devices. While epistemic modal verbs show a strikingly high frequency of occurrences as compared to other epistemic devices in the English corpus, the results of the frequency analysis of the Croatian corpus show that writers hedge their claims mostly by means of the modal verbs, epistemic verbs, and epistemic adverbs and particles, as attested by their overall similar frequencies. With respect to the distribution of epistemic devices across the research article sections, both English and Croatian writers hedge their claims mostly in the Discussion, followed by the Introduction section, while the use of epistemic devices in the remaining two sections is significantly lower by comparison. Generally, this complies with the major rhetorical functions of the research article sections. Thus, the highest density of hedges in the Discussion reflects its major rhetorical functions primarily concerned with writers’ interpretations and implications of the given research, which often requires a cautious and tentative use of language, shielding writers from the risks of negatibilty of the claims. By contrast, the use of hedges in the middle research article sections is less salient given their focus on the descriptive accounts of the methodological procedures and obtained findings. Drawing on Hyland’s (1998) polypragmatic model of scientific hedges, epistemic devices in both corpora are mostly concerned with the reliability type of hedges, concerned with indicating uncertainties towards the propositional content, signaling at the same time the extent to which the claims may be considered as accurate given the limited state of knowledge they are based on. In addition, epistemic markers may be used as writer-oriented hedges concerned with diminishing the writers’ presence in the text, allowing them to maintain distance from the proposed claims. Finally, the use of epistemic verbs co-occurring with the 1st person plural pronouns is interpreted in the present study as a writer’s strategic choice in foregrounding the epistemic stance. This use of epistemic devices is more frequent in the English as compared to the Croatian corpus, which is in line with some previous crosscultural research, indicating that self-mention is a more prominent feature of the Anglo- American writing as compared to that in other languages. In sum, the present findings provide an insight into the use of the epistemic language in the cross-cultural disciplinary writing and as such may be of particular use to the Croatian speaking disciplinary scholars, students and all those interested in writing research articles in English. On a more general note, it is expected that the study may incite further research on academic writing conventions in Croatian or their comparison with those in English as a lingua franca of science.Cilj je rada istražiti kako autori znanstvenih članaka iz područja psihologije na hrvatskom i engleskom jeziku koriste sredstva epistemičke modalnosti da bi izrazili različiti stupanj sigurnosti prema iznesenim tvrdnjama te iskazali stav prema tvrdnjama drugih autora. Analiza se temelji na korpusu 60 znanstvenih članaka objavljenim u znanstvenim časopisima na hrvatskom i engleskom jeziku. Cilj je analize utvrđivanje sličnosti i razlika u uporabi i učestalosti sredstava epistemičke modalnosti u glavnim retoričkim segmentima znanstvenog članka te istraživanje njihovih pragmatičkih funkcija kao sredstava ograđivanja u znanstvenom tekstu. Rezultati frekvencijske analize pokazuju veću zastupljenost sredstava epistemičke modalnosti u engleskom korpusu u odnosu na hrvatski, što je općenito u skladu s nalazima prethodnih međujezičnih istraživanja koja upućuju na učestaliju uporabu oznaka ograđivanja u akademskom stilu angloameričkog govornog područja u odnosu na akademske stilove pisanja u nekim drugim jezicima. Rezultati pokazuju da su modalni glagoli najčešća gramatička kategorija epistemičkih sredstava u oba korpusa, dok su epistemički glagoli sljedeća kategorija po čestotnosti. U oba korpusa najmanju zastupljenost pokazuje uporaba epistemičkih imenica. Unatoč navedenim sličnostima, rezultati analize pokazuju na istaknutu uporabu modalnih glagola u engleskom korpusu, dok učestalost ostalih sredstava epistemičke modalnosti ne pokazuje drastična odstupanja. Rezultati analize hrvatskog korpusa pokazuju da se najčešća sredstva grupiraju oko modalnih glagola, epistemičkih punoznačnih glagola te modalnih priloga i čestica, dok su ostala sredstva značajno manje zastupljena. Nalazi analize ukazuju da se u oba korpusa oznake ograđivanja najviše koriste u Raspravi, manje u Uvodu, dok je značajno manja učestalost zabilježena u Metodi i Rezultatima. Najveća zastupljenost oznaka ograđivanja u Raspravi ukazuje na autorovu potrebu iskazivanja opreza i odmaka u tumačenju nalaza istraživanja i pokušajima izvođenja zaključaka, što proizlazi iz svijesti o različitim ograničenjima istraživanja koja često ne dozvoljavaju iskazivanje visokog stupnja sigurnosti u iznošenju stavova. Manja zastupljenost oznaka ograđivanja u središnjim segmentima članka odražava njihovu primarnu usmjerenost na opise metodoloških postupaka i rezultata, što u pravilu ne zahtijeva izraženiju uporabu oznaka ograđivanja. U odnosu na Hylandov (1998) polipragmatički model ograđivanja u znanstvenom tekstu, rezultati pokazuju da se sredstva epistemičke modalnosti najčešće koriste za iskazivanje nižeg stupnja sigurnosti u odnosu na sadržaj tvrdnje, upućujući pritom da se iste mogu smatrati pouzdanim u okvirima postojećeg, često ograničenog, znanja na temelju kojeg se izvode. Osim na propozicijski sadržaj, pragmatičke funkcije epistemičkih sredstava mogu biti usmjerene i na autora, pri čemu se umanjuje njegova prisutnost u tekstu te omogućuje zadržavanje većeg odmaka od iznesenih tvrdnji. Naposlijetku, uporaba prvog lica i punoznačnih epistemičkih glagola u ovom se radu smatra autorovim izborom s ciljem isticanja osobnog epistemičkog stava. Rezultati pokazuju da je navedena uporaba epistemičkih sredstava učestalija u engleskom korpusu, što je općenito u skladu s nekim prethodnim međujezičnim istraživanjima koja ukazuju da je prisutnost autora istaknutija konvencija angloameričkog akademskog stila pisanja u odnosu na iste u nekim drugim istraživanim jezicima. Zaključno, pretpostavlja se da bi uočene specifičnosti u uporabi sredstava epistemičke modalnosti u psihologijskim člancima u engleskom i hrvatskom jeziku mogle koristiti predmetnim stručnjacima, studentima i svima onima koji počinju pisati ili već imaju iskustvo pisanja znanstvenih članaka kako na hrvatskom, tako i na engleskom jeziku. Očekuje se da bi postojeće istraživanje moglo potaknuti daljnja istraživanja konvencija akademskog pisanja, kako hrvatskog jezika, tako i njihove usporedbe s engleskim jezikom kao globalnim jezikom znanosti

AI Transparency in the Age of LLMs: A Human-Centered Research Roadmap

The rise of powerful large language models (LLMs) brings about tremendous opportunities for innovation but also looming risks for individuals and society at large. We have reached a pivotal moment for ensuring that LLMs and LLM-infused applications are developed and deployed responsibly. However, a central pillar of responsible AI -- transparency -- is largely missing from the current discourse around LLMs. It is paramount to pursue new approaches to provide transparency for LLMs, and years of research at the intersection of AI and human-computer interaction (HCI) highlight that we must do so with a human-centered perspective: Transparency is fundamentally about supporting appropriate human understanding, and this understanding is sought by different stakeholders with different goals in different contexts. In this new era of LLMs, we must develop and design approaches to transparency by considering the needs of stakeholders in the emerging LLM ecosystem, the novel types of LLM-infused applications being built, and the new usage patterns and challenges around LLMs, all while building on lessons learned about how people process, interact with, and make use of information. We reflect on the unique challenges that arise in providing transparency for LLMs, along with lessons learned from HCI and responsible AI research that has taken a human-centered perspective on AI transparency. We then lay out four common approaches that the community has taken to achieve transparency -- model reporting, publishing evaluation results, providing explanations, and communicating uncertainty -- and call out open questions around how these approaches may or may not be applied to LLMs. We hope this provides a starting point for discussion and a useful roadmap for future research

Embedding Predications

Written communication is rarely a sequence of simple assertions. More often, in addition to simple assertions, authors express subjectivity, such as beliefs, speculations, opinions, intentions, and desires. Furthermore, they link statements of various kinds to form a coherent discourse that reflects their pragmatic intent. In computational semantics, extraction of simple assertions (propositional meaning) has attracted the greatest attention, while research that focuses on extra-propositional aspects of meaning has remained sparse overall and has been largely limited to narrowly defined categories, such as hedging or sentiment analysis, treated in isolation. In this thesis, we contribute to the understanding of extra-propositional meaning in natural language understanding, by providing a comprehensive account of the semantic phenomena that occur beyond simple assertions and examining how a coherent discourse is formed from lower level semantic elements. Our approach is linguistically based, and we propose a general, unified treatment of the semantic phenomena involved, within a computationally viable framework. We identify semantic embedding as the core notion involved in expressing extra-propositional meaning. The embedding framework is based on the structural distinction between embedding and atomic predications, the former corresponding to extra-propositional aspects of meaning. It incorporates the notions of predication source, modality scale, and scope. We develop an embedding categorization scheme and a dictionary based on it, which provide the necessary means to interpret extra-propositional meaning with a compositional semantic interpretation methodology. Our syntax-driven methodology exploits syntactic dependencies to construct a semantic embedding graph of a document. Traversing the graph in a bottom-up manner guided by compositional operations, we construct predications corresponding to extra-propositional semantic content, which form the basis for addressing practical tasks. We focus on text from two distinct domains: news articles from the Wall Street Journal, and scientific articles focusing on molecular biology. Adopting a task-based evaluation strategy, we consider the easy adaptability of the core framework to practical tasks that involve some extra-propositional aspect as a measure of its success. The computational tasks we consider include hedge/uncertainty detection, scope resolution, negation detection, biological event extraction, and attribution resolution. Our competitive results in these tasks demonstrate the viability of our proposal

License to Deal: Mandatory Approval of Complex Financial Products

This Article explores the possibility of creating a system of mandatory pre-approval of complex financial products as an ex ante solution to the problem of systemic risk containment. Building on the concept of regulatory precaution borrowed from environmental and health law, and elements of pre-CFMA regulation of commodity futures, the Article outlines the broad contours of a new licensing scheme that would place the burden of proving social and economic utility of complex financial instruments on the intermediaries that structure and market them. Fundamentally a thought experiment, this proposal seeks to enrich the current policy debate by expanding the range of potentially plausible reform options