First-Order Logic Formalisation of Impossibility Theorems in Preference Aggregation

In preference aggregation a set of individuals express preferences over a set of alternatives, and these preferences have to be aggregated into a collective preference. When preferences are represented as orders, aggregation procedures are called social welfare functions. Classical results in social choice theory state that it is impossible to aggregate the preferences of a set of individuals under different natural sets of axiomatic conditions. We define a first-order language for social welfare functions and we give a complete axiomatisation for this class, without having the number of individuals or alternatives specified in the language. We are able to express classical axiomatic requirements in our first-order language, giving formal axioms for three classical theorems of preference aggregation by Arrow, by Sen, and by Kirman and Sondermann. We explore to what extent such theorems can be formally derived from our axiomatisations, obtaining positive results for Sen’s Theorem and the Kirman-Sondermann Theorem. For the case of Arrow’s Theorem, which does not apply in the case of infinite societies, we have to resort to fixing the number of individuals with an additional axiom. In the long run, we hope that our approach to formalisation can serve as the basis for a fully automated proof of classical and new theorems in social choice theory.     

Bilattices with Implications

In a previous work we studied, from the perspective of Abstract Algebraic Logic, the implicationless fragment of a logic introduced by O. Arieli and A. Avron using a class of bilattice-based logical matrices called logical bilattices. Here we complete this study by considering the Arieli-Avron logic in the full language, obtained by adding two implication connectives to the standard bilattice language. We prove that this logic is algebraizable and investigate its algebraic models, which turn out to be distributive bilattices with additional implication operations. We axiomatize and state several results on these new classes of algebras, in particular representation theorems analogue to the well-known one for interlaced bilattices.     

Dissociating the influence of familiarity and meaningfulness from word frequency in naming and lexical decision performance

Performance in two experiments was compared on a list of words of high and low frequency in which familiarity/meaningfulness (FM) was balanced and on a list of high- and low-frequency words in which FM was confounded with frequency (i.e., high frequency--high familiarity vs. low frequency--low familiarity). Both repetition and task (lexical decision and naming) were investigated. In the lexical decision task of Experiment 1, both frequency and repetition effects were larger in the list with FM confounded than in the list with FM matched. In the naming task, frequency and repetition effects and their interaction were significant, but there was no influence of FM list context. In Experiment 2, in which the repetitions occurred across blocks, as opposed to randomly intermixed within a list, similar results were found; however, there was no interaction between list and repetition. The results suggest that an evaluation of items in terms of their meaning and familiarity explains a large part of the variance, only in lexical decision. These dimensions may be cued both by subjective feelings of familiarity and the extent to which semantic information is available and by episodic traces due to recent encounters with the item.     

Psychoanalysis and the Catholic Church in Italy: the role of Father Agostino Gemelli, 1925-1953

Agostino Gemelli, a Catholic priest, psychiatrist, administrator, and educator, was an important figure in the early history of psychoanalysis in Italy. He was one of the few establishment figures to grapple with Freud's ideas in Italy during the first half of the twentieth century, a period during which Italy, compared to the rest of Europe and to the United States, was relatively impermeable to psychoanalysis. One of the factors that contributed to this was the opposition of the powerful Catholic Church, which identified in psychoanalysis a challenge to its authority. The author argues that Father Gemelli's shifting positions about psychoanalysis between 1925 and 1953 reflected the exigencies of his historical circumstances. Gemelli was able to identify in psychoanalysis an integrated view of the human condition in stark opposition to the brutal reductionism of psychiatry in Italy at that time, but also encountered in it elements intolerable to the Church. Examining specifically what it is that Gemelli could accept of psychoanalysis, and what needed to be rejected, between 1925 and 1953, illustrates the particular challenge posed by psychoanalysis to Catholicism in Italy.     

Extent and limits of the matching concept in monkeys (Cebus apella)

In Experiment 1, 8 monkeys, experimentally naive with regard to visual stimuli, were trained on identity matching with a two-sample set based on two-dimensional stimuli. On a subsequent test employing two new samples, 4 of the 8 applied the matching rule to the new sample stimuli (as defined by our transfer criterion), and 3 showed substantial savings in learning to match the new samples. Two of these 3 transferred the matching rule when given a second test with two new samples, and the third showed immediate and complete transfer when tested with a third pair of new stimuli. These results indicate a much stronger representation of the matching concept in monkeys than in pigeons, even when the conditions of assessment are reasonably comparable. In Experiment 2, however, 4 monkeys from Experiment 1 failed to transfer the matching rule to steady versus flashing green samples, indicating that the matching concept did not immediately extend beyond the general class of visual stimuli with which it was developed. These and related results in the literature suggest that representation of the matching concept in animals varies along a specificity-abstractness dimension, reflecting the degree to which the concept is tied to the conditions and context of its development.     

Constraints on the range of context-independent priming from ambiguous words

The semantic priming technique was used to explore the semantic information activated by the contextually irrelevant meanings of ambiguous words in sentence contexts. The nature of the relationship between prime and target was systematically manipulated. Evidence of priming was obtained when the target was an approximate synonym of the prime (e.g., coach-bus), and when the target was a category coordinate of low similarity, but high category typicality (e.g., raincoat jumper, in Italian). No priming was obtained when the target was event related to the prime (coach-driver), nor when it was a highly similar category co-ordinate (raincoat overcoat, in Italian). However, in these latter cases, robust priming effects were obtained when the prime was presented out of context. The results are discussed in terms of the different kinds of semantic-retrieval operations that may be performed, depending upon whether or not the subjects attend to the meaning of the prime.     

Semantic and pragmatic factors in the representation of “near” and “far”

The processing of two spatial terms which refer to proximity and distance, near and far, was investigated in a word-picture comparison task. Two alternative hypotheses were tested, one based on the notion of linguistic markedness and supporting the positive status of far, and the other based on semantic-pragmatic factors and proposing that near is the positive member of the pair. An analysis of the true-false decision latencies indicated that near was generally verified faster than far in judgments in which the terms were used to describe both ego-to-object and object-to-object distance. A third experiment addressed the question of whether the advantage obtained in the verification of near may be accounted for in terms of the priority of the interpersonal dimension of representation relative to the objective one. The results are discussed with regard to the semantic representation of the two words.     

Dissociation of covert and overt spatial attention during prehension movements: Selective interference effects

In four experiments, the influence of distractor objects on the temporal evolution of the reach-tograsp movement toward a target object (an apple) was examined. In the first experiment, the distractor was another apple, which moved laterally behind the target and occasionally changed direction toward the target, thus becoming the to-be-grasped object. In the second and third experiments, the distractor was a stationary piece of fruit, which sometimes became the to-be-grasped object because of a change in illumination. The fourth experiment was a combination of the first two experiments. In all cases, selective interference effects on the transport and manipulation components were observed only when attention to the distractor was covert rather than overt. It is proposed that covert visuospatial attention selects information about distracting but potentially important stimuli, such that a registration of significance is accomplished without the need to process all available information.     

Early markers of lexical stress in visual word recognition

The goal of the present study was to investigate the time-course of suprasegmental information in visual word recognition. To this aim we measured event-related brain potentials (ERPs) during a simple lexical decision task in Italian. Two factors were manipulated: Stress dominance (the most frequent stress type) and stress neighborhood consistency (the proportion and number of existent words sharing orthographic ending and stress pattern). Participants were presented with target words either bearing dominant (on the penultimate syllable; 'graNIta,' 'seNIle,' slush, senile) or non-dominant stress (on the antepenultimate syllable; 'MISsile,' 'BIbita,' missile, drink), and either having a consistent (graNIta, MISsile) or an inconsistent stress neighborhood (seNIle, BIbita). Our results showed in the initial stages of processing an effect that we interpreted as an early orthographic marker of stress neighborhood in interaction with dominance. Later, from 250 ms after target onset, a marker of the lexical stress difference also emerged. The role of stress assignment in word recognition is discussed.