Inexact Knowledge with Introspection

Standard Kripke models are inadequate to model situations of inexact knowledge with introspection, since positive and negative introspection force the relation of epistemic indiscernibility to be transitive and euclidean. Correlatively, Williamson’s margin for error semantics for inexact knowledge invalidates axioms 4 and 5. We present a new semantics for modal logic which is shown to be complete for K45, without constraining the accessibility relation to be transitive or euclidean. The semantics corresponds to a system of modular knowledge, in which iterated modalities and simple modalities are not on a par. We show how the semantics helps to solve Williamson’s luminosity paradox, and argue that it corresponds to an integrated model of perceptual and introspective knowledge that is psychologically more plausible than the one defended by Williamson. We formulate a generalized version of the semantics, called token semantics, in which modalities are iteration-sensitive up to degree n and insensitive beyond n. The multi-agent version of the semantics yields a resource-sensitive logic with implications for the representation of common knowledge in situations of bounded rationality.     

‘Our way of life is worth defending’: testing a model of attitudes towards superordinate group membership through a study of Scots' attitudes towards Britain

This research used a survey design (N = 227) to investigate Scottish people's support or opposition to independence from Britain. It was hypothesised that political attitudes towards supra‐national bodies are not a direct function of the degree of ingroup (Scottish) identification, but are moderated by the extent to which the expression of ingroup identity is seen as being undermined within the larger entity. This feeling of identity undermining is assumed to arise from perceptions of incompatibility with the outgroup and ingroup powerlessness within the common group. The results provided support for these hypotheses. Only for those participants who had high feelings of identity undermining did identification lead to stronger separatist attitudes. Moreover, incompatibility with the outgroup and ingroup powerlessness predicted feelings of identity undermining while this latter mediated their impact on attitudes to being part of Britain. These findings underline the importance of taking into account (a) the contents ascribed to identities and their relations, and (b) the practical ability to pursue a way of live based on these contents in order to understand the way identity processes shape attitudes towards superordinate groups. Copyright © 2008 John Wiley & Sons, Ltd.     

Parsing Pregroup Grammars and Lambek Calculus Using Partial Composition

The paper presents a way to transform pregroup grammars into contextfree grammars using functional composition. The same technique can also be used for the proof-nets of multiplicative cyclic linear logic and for Lambek calculus allowing empty premises.     

Situational consistency in behavioral patterns of aggressive boys: Methodological considerations on observational measures

The issue of situational consistency is of great interest for early intervention with aggressive boys, but efforts to show behavior stability across settings have been unsuccessful to date, due principally to methodological problems. It is argued here that a more appropriate matching of response form, interaction partner, and situations should increase the situation consistency of observed behavior. The results support this proposition in that, more crosssetting behavior consistency was found in the pairing of situations where aggressive boys (age 6–7 years) were interacting with an adult female (mother/child versus baby-sitter/child) than in the pairing of situations where the boys were interacting with an adult male (mother/child versus father/child) or with the teacher in a nondyadic situation (classroom). The implications of using an extreme group are also discussed.This research program was funded by Le Conseil Québécois de la Recherche Sociale, the Quebec Government's FCAR research program, the Social Sciences and Humanities Research Council of Canada, the Canadian Ministry of Employment and Immigration, and the University of Montreal FDR program.     

Apparent duration and spatial structure

In three experiments, we investigated the relative perceived duration of a full bandwidth iniage and a set of high- and lowpass filtered images of a scene, briefly presented on a visual display unit. In Experiment 1, the various images were compared with each other, using a paired comparison method. All images were presented for 40 msec, and observers were asked to judge which of each pair of images had the longest duration. The results showed that images containing a wide spatial frequency bandwidth were judged to be of longer duration than were images of a narrower bandwidth, regardless of whether the latter were high- or lowpass filtered. In Experiment 2, a 40-msec presentation of each of the images was compared with a presentation of a probe that was 20,40, 60, or 80 msec in duration. Observers again judged which of each pair of images had the longest duration. The results were very similar to those of Experiment 1, with wide bandwidth images being judged to be of longer duration than were narrow bandwidth images. In Experiment 3, instead of comparing the various filtered versions of the image with each other, we attempted to obtain a direct measure of perceived duration by comparing a flashing LED to a 40-msec flash of a subset of the images used in the previous experiments. The observers’ task was to adjust the duration of the LED flash to match the perceived duration of each image. The results confirmed the results of the previous experiments, again indicating that wide bandwidth images are perceived to have longer phenomenal durations than narrow bandwidth images are perceived to have. These results could be predicted from previous research in the literature on the effects of spatial frequency on perceptual lag but not from research on visual persistence. It is argued that the effects described here can probably be explained best by postulating a link between perceived duration and the integration of separately processed spatial frequency information.     

PASTIS: A program for curve and distribution analyses

Reaction time (RT) data afford different types of analyses. One type of analysis, called “curve analysis,” can be used to characterize the evolution of performance at different moments over the course of learning. By contrast, distribution analysis aims at characterizing the spread of RTs at a specific moment. Techniques to deduce free parameters are described for both types of analyses, given an a priori choice of the curve or distribution one wants to fit, along with statistical tests of significance for distribution analysis: The log likelihood technique is used if the probability density function is given; otherwise, a root-mean-square-deviation minimization technique is used. A program—PASTIS—that searches for the optimal parameters of the following curves is presented: power law, exponential, and e-based exponential. PASTIS also searches for Weibull and the ex-Gaussian distributions. Some tests of the software are presented.