The enduring scandal of deduction

Deductive inference is usually regarded as being “tautological” or “analytical”: the information conveyed by the conclusion is contained in the information conveyed by the premises. This idea, however, clashes with the undecidability of first-order logic and with the (likely) intractability of Boolean logic. In this article, we address the problem both from the semantic and the proof-theoretical point of view. We propose a hierarchy of propositional logics that are all tractable (i.e. decidable in polynomial time), although by means of growing computational resources, and converge towards classical propositional logic. The underlying claim is that this hierarchy can be used to represent increasing levels of “depth” or “informativeness” of Boolean reasoning. Special attention is paid to the most basic logic in this hierarchy, the pure “intelim logic”, which satisfies all the requirements of a natural deduction system (allowing both introduction and elimination rules for each logical operator) while admitting of a feasible (quadratic) decision procedure. We argue that this logic is “analytic” in a particularly strict sense, in that it rules out any use of “virtual information”, which is chiefly responsible for the combinatorial explosion of standard classical systems. As a result, analyticity and tractability are reconciled and growing degrees of computational complexity are associated with the depth at which the use of virtual information is allowed.     

Logical fallacies as informational shortcuts

The paper argues that the two best known formal logical fallacies, namely denying the antecedent (DA) and affirming the consequent (AC) are not just basic and simple errors, which prove human irrationality, but rather informational shortcuts, which may provide a quick and dirty way of extracting useful information from the environment. DA and AC are shown to be degraded versions of Bayes’ theorem, once this is stripped of some of its probabilities. The less the probabilities count, the closer these fallacies become to a reasoning that is not only informationally useful but also logically valid.     

Perceiving ingroup members who use stereotypes: implicit conformity and similarity

Previous studies have shown that people subtly conform more to ingroup members who use stereotype‐consistent rather than stereotype‐inconsistent information when describing an outgroup member (Castelli, Vanzetto, Sherman, & Arcuri, 2001 ). In the present article, we will address two important issues. First, we will examine whether this subtle conformity toward stereotypers is related to individuals' prejudice level (Study 1). Second, we will examine one of the processes that underlie the perception of ingroup members who use stereotype‐consistent information, hypothesizing that individuals implicitly feel more similar to such sources than to ingroup members who use stereotype‐inconsistent information (Study 2). Both hypotheses were confirmed and results are discussed in terms of the distinction between implicit and explicit attitudes and their implications in the maintenance of social stereotypes. Copyright © 2002 John Wiley & Sons, Ltd.     

Influence of maternal reflective functioning on mothers’ and children's weight: A follow-up study

Based on cross-sectional research linking poor reflective functionining (RF) to eating disorders, the current follow-up study tested whether maternal RF would explain the variance of mothers’ and children's weight beyond the effects of maternal emotional dysregulation. During pregnancy (Time 1 [T1]), 51 women were administered the Difficulties in Emotion Regulation Scale (DERS) and interviewed using the Adult Attachment Interview (AAI). Seven months after delivery (Time 2 [T2]), mother–baby dyads who remained in the study (n = 44) were videotaped (Feeding Scale) during their feeding interaction. Last (Time 3 [T3]), the weight of the 34 children who were still in the study was collected at 3 years of age. Maternal AAI-RF at T1 did not correlate with the DERS at T1 nor with the quality of the feeding interacions at T2. However, it correlated, significantly, with maternal body mass index (BMI) at T1, r = −.298, P = .034, and marginally significantly with baby's BMI at T3, r = −.296, P = .089. Moreover, multiple regression models showed a trend indicating that maternal AAI-RF might explain the variance of mothers’ and children's weight beyond the effects of maternal emotional dysregulation. These findings suggest that working on maternal mentalization might contribute to helping prevent childhood obesity from pregnancy.     

A defence of informational structural realism

This is the revised version of an invited keynote lecture delivered at the 1st Australian Computing and Philosophy Conference (CAP@AU; the Australian National University in Canberra, 31 October–2 November, 2003). The paper is divided into two parts. The first part defends an informational approach to structural realism. It does so in three steps. First, it is shown that, within the debate about structural realism (SR), epistemic (ESR) and ontic (OSR) structural realism are reconcilable. It follows that a version of OSR is defensible from a structuralist-friendly position. Second, it is argued that a version of OSR is also plausible, because not all relata (structured entities) are logically prior to relations (structures). Third, it is shown that a version of OSR is also applicable to both sub-observable (unobservable and instrumentally-only observable) and observable entities, by developing its ontology of structural objects in terms of informational objects. The outcome is informational structural realism, a version of OSR supporting the ontological commitment to a view of the world as the totality of informational objects dynamically interacting with each other. The paper has been discussed by several colleagues and, in the second half, ten objections that have been moved to the proposal are answered in order to clarify it further.     

Depth stratification in illusory-contour figures on heterogeneous backgrounds is independent of contour clarity and brightness enhancement

Depth stratification in illusory-contour figures was studied by superimposing Kanizsa figures on heterogeneous backgrounds. Gaussian-noise textures were employed in two rating-scale experiments to explore observers' judgments of (i) illusory-contour clarity, (ii) brightness enhancement, and (iii) depth stratification. In experiment 1, depth stratification was found to be stronger in heterogeneous conditions. In experiment 2, texture coarseness was manipulated to determine how depth stratification is affected by linear elements of different sizes in the background, and to relate the variation to contour clarity and brightness enhancement. Results suggest that depth stratification is independent of contour clarity and brightness enhancement. Preliminary novel observations on illusory-contour formation are reported.     

Role of serotonin in human aggressive behaviour

This study aimed to evaluate a peripheral serotonergic marker, ³H-imipramine (³H-IMI) binding to platelet membranes, in a group of severely aggressive subjects (A), institutionalized since childhood for mental retardation, as compared with suicide attempters (S) and healthy controls (H). The maximum binding capacity of ³H-IMI to platelet membranes was statistically lower in (A) and (S) than in (H). In addition, a statistically significant difference was observed between the Bmax values of aggressive subjects and those of suicide attempters. No changes in the dissociation constant (Kd) of IMI binding were observed. These data provide further supporting evidence for the hypothesis of an abnormality of the 5HT system in aggressive behaviour and suggest that such an abnormality, as reflected by platelet markers, is more severe in suicide attempters. © 1993 Wiley-Liss, Inc.     

Effect of previous fighting on the dynamic of agonistic encounters in zebrafish males

Animal Cognition - Aggression among individuals which compete for resources such as food or territory, or to establish dominance relationships, can cause injuries that may be risky for the...