165 research outputs found

    The information effect: Constructive memory, testimony, and epistemic luck

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    Cataloged from PDF version of article.The incorporation of post-event testimonial information into an agent’s memory representation of the event via constructive memory processes gives rise to the misinformation effect, in which the incorporation of inaccurate testimonial information results in the formation of a false memory belief. While psychological research has focussed primarily on the incorporation of inaccurate information, the incorporation of accurate information raises a particularly interesting epistemological question: do the resulting memory beliefs qualify as knowledge? It is intuitively plausible that they do not, for they appear to be only luckily true. I argue, however, that, despite its intuitive plausibility, this view is mistaken: once we adopt an adequate (modal) conception of epistemic luck and an adequate (adaptive) general approach to memory, it becomes clear that memory beliefs resulting from the incorporation of accurate testimonial information are not in general luckily true. I conclude by sketching some implications of this argument for the psychology of memory, suggesting that the misinformation effect would better be investigated in the context of a broader “information effect”

    Opening the doors of memory: Is declarative memory a natural kind?

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    Klein's target article argues that autonoetic consciousness is a necessary condition for memory; this unusually narrow view of the scope of memory implies that only episodic memory is, strictly speaking, memory. The narrow view is opposed to the standard broad view, on which causal connection with past experience is sufficient for memory; on the broad view, both declarative (i.e., episodic and semantic) and procedural memory count as genuine forms of memory. Klein mounts a convincing attack on the broad view, arguing that it opens the "doors of memory" too far, but this commentary contends that the narrow view does not open them far enough. It may be preferable to adopt an intermediate view of the scope of memory, on which causal connection is sufficient for memory only when it involves encoding, storage, and retrieval of content. More demanding than the simple causal condition but less demanding than the autonoesis condition, the encoding-storage-retrieval condition implies that both episodic and semantic memory count as genuine forms of memory but that procedural memory does not

    Anatomy of the Soft-Photon Approximation in Hadron-Hadron Bremsstrahlung

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    A modified Low procedure for constructing soft-photon amplitudes has been used to derive two general soft-photon amplitudes, a two-s-two-t special amplitude MÎŒTsTtsM^{TsTts}_{\mu} and a two-u-two-t special amplitude MÎŒTuTtsM^{TuTts}_{\mu}, where s, t and u are the Mandelstam variables. MÎŒTsTtsM^{TsTts}_{\mu} depends only on the elastic T-matrix evaluated at four sets of (s,t) fixed by the requirement that the amplitude be free of derivatives (∂\partialT/∂\partials and /or ∂\partialT/∂t\partial t). Likewise MÎŒTuTtsM^{TuTts}_{\mu} depends only on the elastic T-matrix evaluated at four sets of (u,t). In deriving these amplitudes, we impose the condition that MÎŒTsTtsM^{TsTts}_{\mu} and MÎŒTuTtsM^{TuTts}_{\mu} reduce to MˉΌTsTts\bar{M}^{TsTts}_{\mu} and MˉΌTuTts\bar{M}^{TuTts}_{\mu}, respectively, their tree level approximations. The amplitude MˉΌTsTts\bar{M}^{TsTts}_{\mu} represents photon emission from a sum of one-particle t-channel exchange diagrams and one-particle s-channel exchange diagrams, while the amplitude MˉΌTuTts\bar{M}^{TuTts} _{\mu} represents photon emission from a sum of one-particle t-channel exchange diagrams and one-particle u-channel exchange diagrams. The precise expressions for MˉΌTsTts\bar{M}^{TsTts}_{\mu} and MˉΌTuTts\bar{M}^{TuTts}_{\mu} are determined by using the radiation decomposition identities of Brodsky and Brown. We point out that it is theoretically impossible to describe all bremsstrahlung processes by using only a single class of soft-photon amplitudes. At least two different classes are required: the amplitudes which depend on s and t or the amplitudes which depend on u and t. When resonance effects are important, the amplitude MÎŒTsTtsM^{TsTts}_{\mu}, not MÎŒLow(st)M^{Low(st)}_{\mu}, should be used. For processes with strong u-channel exchange effects, the amplitude MÎŒTuTtsM^{TuTts}_{\mu} should be the first choice.Comment: 49 pages report # LA-UR-92-270

    Metacognition as Evidence for Evidentialism

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    Metacognition is the monitoring and controlling of cognitive processes. I examine the role of metacognition in ‘ordinary retrieval cases’, cases in which it is intuitive that via recollection the subject has a justiïŹed belief. Drawing on psychological research on metacognition, I argue that evidentialism has a unique, accurate prediction in each ordinary retrieval case: the subject has evidence for the proposition she justiïŹedly believes. But, I argue, process reliabilism has no unique, accurate predictions in these cases. I conclude that ordinary retrieval cases better support evidentialism than process reliabilism. This conclusion challenges several common assumptions. One is that non-evidentialism alone allows for a naturalized epistemology, i.e., an epistemology that is fully in accordance with scientiïŹc research and methodology. Another is that process reliabilism fares much better than evidentialism in the epistemology of memory

    Proton-proton bremsstrahlung below and above pion-threshold: the influence of the Δ\Delta-isobar

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    The proton-proton bremsstrahlung is investigated within a coupled-channel model with the Δ\Delta degree of freedom. The model is consistent with the NNNN scattering up to 1 GeV and the ÎłNΔ\gamma N\Delta vertex determined in the study of pion photoproduction reactions. It is found that the Δ\Delta excitation can significantly improve the agreements with the pp→ppÎłpp \rightarrow pp\gamma at Elab=280E_{lab}=280 MeV. Predictions at Elab=550E_{lab}=550 and 800800 MeV are presented for future experimental tests.Comment: 26 pages Revtex, 12 figures are available from the authors upon request ([email protected]

    Delta--Excitation and Exchange Corrections for NN--Bremsstrahlung

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    The role of the relativistic amplitudes for a number of O(k){\cal O}(k) processes usually neglected in potential model calculations of NN--bremsstrahlung is investigated. In particular, we consider the Δ\Delta--excitation pole contributions related to the one--pion and one--rho exchange and in addition include the exchange contributions induced by the radiative ω,â€‰Ïâ†’Ï€Îł\omega,\,\rho \to \pi \gamma decays. The contributions are calculated from relativistic Born amplitudes fitted to Δ\Delta--production and absorption data in the energy range up to 1 GeV and then used to supplement potential model and soft photon calculations for nucleon--nucleon bremsstrahlung. The effects on NNÎłNN\gamma--observables, although moderate in general, are found to be important in some kinematic domains.Comment: 15 pages in LaTex, using Revtex, 6 figures as uufile'd, compressed Postscript file included, TRIUMF preprint TRI-PP-94-9

    Field transformations and simple models illustrating the impossibility of measuring off-shell effects

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    In the context of simple models illustrating field transformations in Lagrangian field theories we discuss the impossibility of measuring off-shell effects in nucleon-nucleon bremsstrahlung, Compton scattering, and related processes. To that end we introduce a simple phenomenological Lagrangian describing nucleon-nucleon bremsstrahlung and perform an appropriate change of variables leading to different off-shell behavior in the nucleon-nucleon amplitude as well as the photon-nucleon vertex. As a result we obtain a class of equivalent Lagrangians, generating identical S-matrix elements, of which the original Lagrangian is but one representative. We make use of this property in order to show that what appears as an off-shell effect in an S-matrix element for one Lagrangian may originate in a contact term from an equivalent Lagrangian. By explicit calculation we demonstrate for the case of nucleon-nucleon bremsstrahlung as well as nucleon Compton scattering the equivalence of observables from which we conclude that off-shell effects cannot in any unambiguous way be extracted from an S-matrix element. Finally, we also discuss some implications of introducing off-shell effects on a phenomenological basis, resulting from the requirement that the description of one process be consistent with that of other processes described by the same Lagrangian.Comment: 19 pages, Latex, using RevTe
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