132,674 research outputs found

    Exploration and Exploitation of Victorian Science in Darwin's Reading Notebooks

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    Search in an environment with an uncertain distribution of resources involves a trade-off between exploitation of past discoveries and further exploration. This extends to information foraging, where a knowledge-seeker shifts between reading in depth and studying new domains. To study this decision-making process, we examine the reading choices made by one of the most celebrated scientists of the modern era: Charles Darwin. From the full-text of books listed in his chronologically-organized reading journals, we generate topic models to quantify his local (text-to-text) and global (text-to-past) reading decisions using Kullback-Liebler Divergence, a cognitively-validated, information-theoretic measure of relative surprise. Rather than a pattern of surprise-minimization, corresponding to a pure exploitation strategy, Darwin's behavior shifts from early exploitation to later exploration, seeking unusually high levels of cognitive surprise relative to previous eras. These shifts, detected by an unsupervised Bayesian model, correlate with major intellectual epochs of his career as identified both by qualitative scholarship and Darwin's own self-commentary. Our methods allow us to compare his consumption of texts with their publication order. We find Darwin's consumption more exploratory than the culture's production, suggesting that underneath gradual societal changes are the explorations of individual synthesis and discovery. Our quantitative methods advance the study of cognitive search through a framework for testing interactions between individual and collective behavior and between short- and long-term consumption choices. This novel application of topic modeling to characterize individual reading complements widespread studies of collective scientific behavior.Comment: Cognition pre-print, published February 2017; 22 pages, plus 17 pages supporting information, 7 pages reference

    Neural signals encoding shifts in beliefs

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    Dopamine is implicated in a diverse range of cognitive functions including cognitive flexibility, task switching, signalling novel or unexpected stimuli as well as advance information. There is also longstanding line of thought that links dopamine with belief formation and, crucially, aberrant belief formation in psychosis. Integrating these strands of evidence would suggest that dopamine plays a central role in belief updating and more specifically in encoding of meaningful information content in observations. The precise nature of this relationship has remained unclear. To directly address this question we developed a paradigm that allowed us to decompose two distinct types of information content, information-theoretic surprise that reflects the unexpectedness of an observation, and epistemic value that induces shifts in beliefs or, more formally, Bayesian surprise. Using functional magnetic-resonance imaging in humans we show that dopamine-rich midbrain regions encode shifts in beliefs whereas surprise is encoded in prefrontal regions, including the pre-supplementary motor area and dorsal cingulate cortex. By linking putative dopaminergic activity to belief updating these data provide a link to false belief formation that characterises hyperdopaminergic states associated with idiopathic and drug induced psychosis

    Final report TransForum WP-046 : images of sustainable development of Dutch agriculture and green space

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    In the project “Images of sustainable development of Dutch agriculture and green space” three PhD candidates studied the topic of images in sustainable development. Frans Hermans focused on the topic of societal images and their role and influence in innovation projects. The title of his subproject was “Social learning for sustainability in dynamic agricultural innovation networks.” Joost Vervoort explored the topic of “visualisation”, that is, using and producing images for specific purposes, in the context of innovation projects and programmes, in a subproject called “Step into the system: interactive media strategies for the exchange of insights on social-ecological change.” Finally, Dirk van Apeldoorn took a complex adaptive systems approach to images. He modelled various agro-ecosystems to compare images of those systems with the behaviour of those systems. His subproject was called “Modeling resilience of agro-ecosystems.

    Dialogical encounter argument as a source of rigour in the practice based PhD

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    This paper distinguishes between three views of argument: “argument as structure,” “argument as confrontation” and “argument as dialogical encounter.” Empirical studies of the criteria that examiners bring to the assessment of PhDs are cited. The studies provide evidence that qualities that align one or other of the three modes of argument figure significantly in the criteria that examiners bring to the assessment process. Embedded in the studies are respondents’ comments that suggest that the range of conceptions of argument held by PhD examiners is broad. Explicit use of the term “argument” is often made in reference to a minimal concept of argument ¬– “argument as structure.” However, the reported comments indicate a significant bias towards qualities associated with concepts of argument that lie somewhere along the spectrum between “argument as confrontation” and “argument as dialogical encounter” as a marker of quality in PhD research. Drawing on the work of Hans Georg Gadamer the paper will explore the possibilities opened up by adopting the view of “argument as dialogical encounter” in the context of the PhD. In particular I consider the issue of how PhD projects be structured so as to support the construction of arguments appropriate to practice based research in design? Keywords: Argument; Gadamer; Hermeneutics; Rigour; Practice Based Research; Phd Examination</p

    ”Other” or “one of us”?: the porn user in public and academic discourse

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    The consumption of sexually explicit media has long been a matter of public and political concern. It has also been a topic of academic interest. In both these arenas a predominantly behaviourist model of effects and regulation has worked to cast the examination of sexually explicit texts and their consumption as a debate about harm. The broader area of investigation remains extraordinarily undeveloped. Sexually explicit media is a focus of interest for academics because of the way it ‘speaks’ sex and sexuality for its culture. In this paper I examine existing and emerging figures of the porn consumer, their relation to ways of thinking and speaking about pornography, and the implications of these for future work on porn consumption. </p

    Using term clouds to represent segment-level semantic content of podcasts

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    Spoken audio, like any time-continuous medium, is notoriously difficult to browse or skim without support of an interface providing semantically annotated jump points to signal the user where to listen in. Creation of time-aligned metadata by human annotators is prohibitively expensive, motivating the investigation of representations of segment-level semantic content based on transcripts generated by automatic speech recognition (ASR). This paper examines the feasibility of using term clouds to provide users with a structured representation of the semantic content of podcast episodes. Podcast episodes are visualized as a series of sub-episode segments, each represented by a term cloud derived from a transcript generated by automatic speech recognition (ASR). Quality of segment-level term clouds is measured quantitatively and their utility is investigated using a small-scale user study based on human labeled segment boundaries. Since the segment-level clouds generated from ASR-transcripts prove useful, we examine an adaptation of text tiling techniques to speech in order to be able to generate segments as part of a completely automated indexing and structuring system for browsing of spoken audio. Results demonstrate that the segments generated are comparable with human selected segment boundaries
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