Integration of base rates and new information in an abstract hypothesis‐testing task

In two studies, we investigated how people use base rates and the presence versus the absence of new information to judge which of two hypotheses is more likely. Participants were given problems based on two decks of cards printed with 0–4 letters. A table showed the relative frequencies of the letters on the cards within each deck. Participants were told the letters that were printed on or absent from a card the experimenter had drawn. Base rates were conveyed by telling participants that the experimenter had chosen the deck by drawing from an urn containing, in different proportions, tickets marked either ‘deck 1’ or ‘deck 2’. The task was to judge from which of the two decks the card was most likely drawn. Prior probabilities and the evidential strength of the subset of present clues (computed as ‘weight of evidence’) were the only significant predictors of participants’ dichotomous (both studies) and continuous (Study 2) judgments. The evidential strength of all clues was not a significant predictor of participants’ judgments in either study, and no significant interactions emerged. We discuss the results as evidence for additive integration of base rates and the new present information in hypothesis testing.     

Cannabis use and the risk behavior syndrome in Italian university students: are they related to suicide risk?

The aim of this study was to examine the association of cannabis use with risky behaviors and suicide risk in university students. A convenience sample of 246 students was recruited from four universities in Rome during the 2004 academic year. Participants completed the Zung scales for anxiety and depression, the Suicide Score Scale, and an ad hoc questionnaire assessing risky behaviors. The findings indicated a widespread use of cannabis among students and its association with risky behaviors, anxiety and depression, and suicide risk. A regression tree analysis resulted in 3 splits indicating that the Zung Self-Rating Depression Scale is a good predictor of suicide risk, discriminating individuals at lower risk from those at higher risk. Individuals at higher risk for suicide could also be discriminated by self-reported lifetime drug use. Limitations of the study are related to the small sample size and use of a convenience sample.     

Sensitivity to social contingency or stability of interaction? Modelling the dynamics of perceptual crossing

We introduce a series of evolutionary robotics simulations that address the behaviour of individuals in socially contingent interactions. The models are based on a recent study by Auvray, Lenay and Stewart [(2006). The attribution of intentionality in a simulated environment: The case of minimalist devices. In Tenth meeting of the association for the scientific study of consciousness, Oxford, UK, 23-26 June, 2006] on tactile perceptual crossing in a minimal virtual environment. In accordance, both the empirical experiments and our simulations point out the essential character of global embodied interaction dynamics for the sensitivity to contingency to arise. Rather than being individually perceived by any of the interactors, sensitivity to contingency arises from processes of circular causality that characterise the collective dynamics. Such global dynamical aspects are frequently neglected when studying social cognition. Furthermore, our synthetic studies point out interesting aspects of the task that are not immediately obvious in the empirical data. They, in addition, generate new hypotheses for further experiments. We conclude by promoting a minimal but tractable, dynamic and embodied account to social interaction, combining synthetic and empirical findings as well as concrete predictions regarding sensorimotor strategies, the role of time-delays and robustness to perturbations in interactive dynamics.     

Aristotle on a Puzzle about Logical Consequence: Necessity of Being vs. Necessity of Saying

In the Posterior Analytics (I 6, 75a18–27) Aristotle discusses a puzzle which endangers the possibility of inferring a non-necessary conclusion. His solution relies on the distinction between the necessity of the conclusion's being the case and the necessity of admitting the conclusion once one has admitted the premisses. The former is a factual necessity, whereas the latter is meant to be a normative or deontic necessity that is independent of the facts stated by the premisses and the conclusion. This paper maintains that Aristotle resorts to this distinction because he thinks that, as long as it is conceived as a factual relation, logical consequence cannot exist independently of the facts expressed by the premisses and the conclusion. As a corollary, the necessity of such a consequence relation always requires the necessity of these facts. Aristotle holds this factual conception of logical consequence responsible for the puzzle, since it cannot account for valid syllogisms with contingent or false premisses. The alternative conception of necessity is then introduced by him in order to make good this deficiency. The distinction between the necessity of being and the necessity of saying was revived by the Oxford logician E. W. B. Joseph, and taken over by Frank Ramsey in his seminal Truth and Probability, but has not received attention from recent interpreters of Aristotle's logic. This paper, however, argues that, in spite of its intrinsic interest, the distinction bore no significant fruit in Aristotle's logical doctrine.     

Aristotle on the Liar

Topoi - The only passage from Aristotle's works that seemsto discuss the paradox of the liar is within chapter 25 of Sophistici Elenchi (180a34–b7). This passage raises several questions:...     

Mediating and moderating processes in the relationship between multicultural ideology and attitudes towards immigrants in emerging adults

Few studies examine intercultural relations in emerging adulthood. Framed from the perspective of the Mutual Intercultural Relations in Plural Societies (MIRIPS) project, the current paper examined the mediating role of tolerance and perceived consequences of immigration in the relationship between multicultural ideology and attitudes towards immigrants. Additionally, the moderating role of context was analysed. A two‐group structural equation modelling was performed on data collected from 305 Italian emerging adults living both in northern and in southern Italy with different socio‐political climates towards immigrants. In both groups, tolerance and perceived consequences of immigration mediated the relationship between multicultural ideology and attitudes towards immigrants. Also, this indirect relationship was significantly higher for the northern than southern Italians. These findings provide provisional evidence of mediating and moderating processes in the relationship between multicultural ideology and attitudes towards immigrants and suggest important implications for practitioners interested in promoting intercultural relations among emerging adults.     

Predicting pleasure at others’ misfortune: Morality trumps sociability and competence in driving deservingness and schadenfreude

Schadenfreude occurs when people feel pleasure at others’ misfortunes. Previous research suggested that individuals feel such a malicious pleasure when the misfortune befalls social targets perceived as highly competent but lacking human warmth. Two experiments explored whether the two components of warmth (i.e., sociability and morality) have distinct roles in driving schadenfreude. Study 1 (N = 128) compared a competent but immoral individual to a competent but unsociable person and found that people felt more schadenfreude when a misfortune befell an individual lacking morality. Study 2 (N = 199) confirmed the primary role of morality in driving schadenfreude by manipulating not only morality and sociability, but also competence. Moreover, both experiments showed that social targets lacking moral qualities elicited higher levels of schadenfreude because their misfortunes were perceived as deserved. Overall, our findings suggest that morality has a primary role over other basic dimensions of person perception (i.e., sociability and competence) in driving schadenfreude.     

Working memory in healthy aging and in Parkinson’s disease: evidence of interference effects

Focusing on relevant information while suppressing the irrelevant one are critical abilities for different cognitive processes. However, their functioning has been scarcely investigated in the working memory (WM) domain, in both healthy and pathological conditions. The present research aimed to study these abilities in aging and Parkinson’s disease (PD), testing three groups of healthy participants (young, older and elderly) and one of PD patients, employing a new experimental paradigm. Results showed that the transient storing of irrelevant information in WM causes substantial interference effects, which were remarkable in elderly individuals on both response latency and accuracy. Interestingly, PD patients responded faster and were equally accurate compared to a matched control group. Taken together, findings confirm the existence of similar mechanisms for orienting attention inwards to WM contents or outwards to perceptual stimuli, and suggest the suitability of our task to assess WM functioning in both healthy aging and PD.