Buying a passport to heaven: Usury, restitution, and the merchants of medieval Genoa

Historians have argued that the ecclesiastic ban on loans at interest delayed the development of capital markets in the middle ages, and have supported this by pointing to well-documented cases of restitutions of usurious gains by famous moneylenders. Strictly, however, such evidence does not prove that usury laws affected lending, because donations by rich bankers may reflect other motivations. If usury laws had an impact, we have to exclude the Medicis or the Fuggers from the sample, and look for it among the small moneylenders of medieval Europe. Data from late medieval Genoa show that donations by merchants were no greater than those of the population at large once personal wealth is accounted for. However, among merchants the value of pious bequests correlates more closely with mercantile activity than personal wealth, a finding that supports the view that usury laws created an effective constraint on medieval capital markets.     

Response additivity: effects of superimposed free reinforcement on a variable-interval baseline

Three experiments examined the effects of superimposing free reinforcement (Free VI 30-sec) on behavior maintained by a response dependent mult VI 2-min VI 2-min schedule of reinforcement. Experiment I used pigeons as subjects, key pecking as the response, and colors of response key as the stimuli associated with the multiple-schedule components. When free reinforcement was added during only one component (Differential condition) a large and highly significant increase in response rate developed in this component. Adding free reinforcement during both components (Nondifferential condition) produced smaller and far less-consistent effects. An entirely different pattern of results was obtained in two subsequent experiments, where similar procedures and reinforcement conditions were used with rats as subjects and bar pressing as the response. In both Experiments II and III, response rates decreased to the stimulus associated with added free reinforcement in the Differential condition. These findings are interpreted as the result of interactions between behavior maintained by response-reinforcer contingencies and behavior maintained by stimulus-reinforcer contingencies. As such, they support the main assumption of an autoshaping theory of behavioral contrast, that additivity of responding generated by the two kinds of contingency can occur only in situations favorable to autoshaping.     

Williamson on Counterpossibles

A counterpossible conditional is a counterfactual with an impossible antecedent. Common sense delivers the view that some such conditionals are true, and some are false. In recent publications, Timothy Williamson has defended the view that all are true. In this paper we defend the common sense view against Williamson’s objections.     

Some Notes on Boolos’ Semantics: Genesis,Ontological Quests and Model-Theoretic Equivalence to Standard Semantics

The main aim of this work is to evaluate whether Boolos’ semantics for second-order languages is model-theoretically equivalent to standard model-theoretic semantics. Such an equivalence result is, actually, directly proved in the “Appendix”. I argue that Boolos’ intent in developing such a semantics is not to avoid set-theoretic notions in favor of pluralities. It is, rather, to prevent that predicates, in the sense of functions, refer to classes of classes. Boolos’ formal semantics differs from a semantics of pluralities for Boolos’ plural reading of second-order quantifiers, for the notion of plurality is much more general, not only of that set, but also of class. In fact, by showing that a plurality is equivalent to sub-sets of a power set, the notion of plurality comes to suffer a loss of generality. Despite of this equivalence result, I maintain that Boolos’ formal semantics does not committ (directly) second-order languages (theories) to second-order entities (and to set theory), contrary to standard semantics. Further, such an equivalence result provides a rationale for many criticisms to Boolos’ formal semantics, in particular those by Resnik and Parsons against its alleged ontological innocence and on its Platonistic presupposition. The key set-theoretic notion involved in the equivalence proof is that of many-valued function. But, first, I will provide a clarification of the philosophical context and theoretical grounds of the genesis of Boolos’ formal semantics.     

Do dogs exhibit jealous behaviors when their owner attends to their companion dog?

Jealousy appears to have clear adaptive functions across species: it emerges when an important social relationship with a valued social partner is threatened by third-party that is perceived as a rival. Dyads of dogs living together and their owners were tested adapting a procedure devised to study jealousy in young human siblings. Owners at first ignored both dogs while reading a magazine (Control episode), and then petted and praised one of the dogs while ignoring the other, and vice versa (Experimental episodes). We found several differences in the dogs’ behavior between the Experimental episodes and the Control episode, even though only monitoring (gazing at the owner) was exhibited for a significantly greater amount of time in the Experimental episodes. Remarkable individual behavioral differences emerged, suggesting that the dogs’ reactions could be influenced by the relationships that they establish with their owner and the companion dog. Overall, current results do not clearly support our prediction that the ignored dogs would exhibit more behaviors aimed at regaining the owner’s attention when their owner directed attention and care to a companion dog, compared to the control situation. The great intra- and inter-dyad behavioral variability and the choice to test cohabiting dogs could have prevented the emergence of a clear jealous reaction. These findings do not exclude that dogs may exhibit a primordial form of jealousy in a realistic situation, but an additional research is needed to fully gauge which situations, if any, could trigger jealousy in dogs and to rule out alternative explanations.     

New protocol for dissociating visuospatial working memory ability in reaching space and in navigational space

Several studies have demonstrated that the processing of visuospatial memory for locations in reaching space and in navigational space is supported by independent systems, and that the coding of visuospatial information depends on the modality of the presentation (i.e., sequential or simultaneous). However, these lines of evidence and the most common neuropsychological tests used by clinicians to investigate visuospatial memory have several limitations (e.g., they are unable to analyze all the subcomponents of this function and are not directly comparable). Therefore, we developed a new battery of tests that is able to investigate these subcomponents. We recruited 71 healthy subjects who underwent sequential and simultaneous navigational tests by using an innovative sensorized platform, as well as comparable paper tests to evaluate the same components in reaching space (Exp. 1). Consistent with the literature, the principal-component method of analysis used in this study demonstrated the presence of distinct memory for sequences in different portions of space, but no distinction was found for simultaneous presentation, suggesting that different modalities of eye gaze exploration are used when subjects have to perform different types of tasks. For this purpose, an infrared Tobii Eye-Tracking X50 system was used in both spatial conditions (Exp. 2), showing that a clear effect of the presentation modality was due to the specific strategy used by subjects to explore the stimuli in space. Given these findings, the neuropsychological battery established in the present study allows us to show basic differences in the normal coding of stimuli, which can explain the specific visuospatial deficits found in various neurological conditions.     

Working memory deficits, increased anxiety-like traits, and seizure susceptibility in BDNF overexpressing mice

BDNF regulates components of cognitive processes and has been implicated in psychiatric disorders. Here we report that genetic overexpression of the BDNF mature isoform (BDNF-tg) in female mice impaired working memory functions while sparing components of fear conditioning. BDNF-tg mice also displayed reduced breeding efficiency, higher anxiety-like scores, high self-grooming, impaired prepulse inhibition, and higher susceptibility to seizures when placed in a new empty cage, as compared with wild-type (WT) littermate controls. Control measures of general health, locomotor activity, motor coordination, depression-related behaviors, and sociability did not differ between genotypes. The present findings, indicating detrimental effects of life-long increased BDNF in mice, may inform human studies evaluating the role of BDNF functional genetic variations on cognitive abilities and vulnerability to psychiatric disorders.     

When does mimicry affect evaluative judgment?

We investigated the effect of subliminally presented happy or angry faces on evaluative judgments when the facial muscles of participants were free to mimic or blocked. We hypothesized and showed that subliminally presented happy expressions lead to more positive judgments of cartoons compared to angry expressions only when facial muscles were not blocked. These results reveal the influence of socially driven embodied processes on affective judgments and have also potential implications for phenomena such as emotional contagion. (PsycINFO Database Record (c) 2011 APA, all rights reserved).