Working memory capacity can be improved by recoding the memorized information in a condensed form. Here, we tested the theory that human adults encode binary sequences of stimuli in memory using an abstract internal language and a recursive compression algorithm. The theory predicts that the psychological complexity of a given sequence should be proportional to the length of its shortest description in the proposed language, which can capture any nested pattern of repetitions and alternations using a limited number of instructions. Five experiments examine the capacity of the theory to predict human adults' memory for a variety of auditory and visual sequences. We probed memory using a sequence violation paradigm in which participants attempted to detect occasional violations in an otherwise fixed sequence. Both subjective complexity ratings and objective violation detection performance were well predicted by our theoretical measure of complexity, which simply reflects a weighted sum of the number of elementary instructions and digits in the shortest formula that captures the sequence in our language. While a simpler transition probability model, when tested as a single predictor in the statistical analyses, accounted for significant variance in the data, the goodness-of-fit with the data significantly improved when the language-based complexity measure was included in the statistical model, while the variance explained by the transition probability model largely decreased. Model comparison also showed that shortest description length in a recursive language provides a better fit than six alternative previously proposed models of sequence encoding. The data support the hypothesis that, beyond the extraction of statistical knowledge, human sequence coding relies on an internal compression using language-like nested structures.

The capacity to store information in working memory strongly depends upon the ability to recode the information in a compressed form. Here, we tested the theory that human adults encode binary sequences of stimuli in memory using a recursive compression algorithm akin to a “language of thought”, and capable of capturing nested patterns of repetitions and alternations. In five experiments, we probed memory for auditory or visual sequences using both subjective and objective measures. We used a sequence violation paradigm in which participants detected occasional violations in an otherwise fixed sequence. Both subjective ratings of complexity and objective sequence violation detection rates were well predicted by complexity, as measured by minimal description length (also known as Kolmogorov complexity) in the binary version of the “language of geometry”, a formal language previously found to account for the human encoding of complex spatial sequences in the proposed language. We contrasted the language model with a model based solely on surprise given the stimulus transition probabilities. While both models accounted for variance in the data, the language model dominated over the transition probability model for long sequences (with a number of elements far exceeding the limits of working memory). We use model comparison to show that the minimal description length in a recursive language provides a better fit than a variety of previous encoding models for sequences. The data support the hypothesis that, beyond the extraction of statistical knowledge, human sequence coding relies on an internal compression using language-like nested structures.

Recent approaches to human concept learning have successfully combined the power of symbolic, infinitely productive rule systems and statistical learning to explain our ability to learn new concepts from just a few examples. The aim of most of these studies is to reveal the underlying language structuring these representations and providing a general substrate for thought. However, describing a model of thought that is fixed once trained is against the extensive literature that shows how experience shapes concept learning. Here, we ask about the plasticity of these symbolic descriptive languages. We perform a concept learning experiment that demonstrates that humans can change very rapidly the repertoire of symbols they use to identify concepts, by compiling expressions that are frequently used into new symbols of the language. The pattern of concept learning times is accurately described by a Bayesian agent that rationally updates the probability of compiling a new expression according to how useful it has been to compress concepts so far. By portraying the language of thought as a flexible system of rules, we also highlight the difficulties to pin it down empirically.

Probabilistic proposals of Language of Thoughts (LoTs) can explain learning across different domains as statistical inference over a compositionally structured hypothesis space. While frameworks may differ on how a LoT may be implemented computationally, they all share the property that they are built from a set of atomic symbols and rules by which these symbols can be combined. In this work we propose an extra validation step for the set of atomic productions defined by the experimenter. It starts by expanding the defined LoT grammar for the cognitive domain with a broader set of arbitrary productions and then uses Bayesian inference to prune the productions from the experimental data. The result allows the researcher to validate that the resulting grammar still matches the intuitive grammar chosen for the domain. We then test this method in the language of geometry, a specific LoT model for geometrical sequence learning. Finally, despite the fact of the geometrical LoT not being a universal (i.e. Turing-complete) language, we show an empirical relation between a sequence's probability and its complexity consistent with the theoretical relationship for universal languages described by Levin's Coding Theorem.

Recent approaches to human concept learning have successfully combined the power of symbolic, infinitely productive, rule systems and statistical learning. The aim of most of these studies is to reveal the underlying language structuring these representations and providing a general substrate for thought. Here, we ask about the plasticity of symbolic descriptive languages. We perform two concept learning experiments, that consistently demonstrate that humans can change very rapidly the repertoire of symbols they use to identify concepts, by compiling expressions which are frequently used into new symbols of the language. The pattern of concept learning times is accurately described by a Bayesian agent that rationally updates the probability of compiling a new expression according to how useful it has been to compress concepts so far. By portraying the Language of Thought as a flexible system of rules, we also highlight the intrinsic difficulties to pin it down empirically.

In this paper, we present a theoretical effort to connect the theory of program size to psychology by implementing a concrete language of thought with Turing-computable Kolmogorov complexity ($LT^2C^2$ ) satisfying the following requirements: 1) to be simple enough so that the complexity of any given finite binary sequence can be computed, 2) to be based on tangible operations of human reasoning (printing, repeating,. . . ), 3) to be sufficiently powerful to generate all possible sequences but not too powerful as to identify regularities which would be invisible to humans. We first formalize $LT^2C^2$ , giving its syntax and semantics, and defining an adequate notion of program size. Our setting leads to a Kolmogorov complexity function relative to $LT^2C^2$ which is computable in polynomial time, and it also induces a prediction algorithm in the spirit of Solomonoff’s inductive inference theory. We then prove the efficacy of this language by investigating regularities in strings produced by participants attempting to generate random strings. Participants had a profound understanding of randomness and hence avoided typical misconceptions such as exaggerating the number of alternations. We reasoned that remaining regularities would express the algorithmic nature of human thoughts, revealed in the form of specific patterns. Kolmogorov complexity relative to $LT^2C^2$ passed three expected tests examined here: 1) human sequences were less complex than control PRNG sequences, 2) human sequences were not stationary showing decreasing values of complexity resulting from fatigue 3) each individual showed traces of algorithmic stability since fitting of partial data was more effective to predict subsequent data than average fits. This work extends on previous efforts to combine notions of Kolmogorov complexity theory and algorithmic information theory to psychology, by explicitly proposing a language which may describe the patterns of human thoughts.Received: 12 December 2012, Accepted: 3 February 2013; Edited by: G. Mindlin; DOI: http://dx.doi.org/10.4279/PIP.050001Cite as: S Romano, M Sigman, S Figueira, Papers in Physics 5, 050001 (2013)

The theme of this afternoon’s session is theology and religion. We have been lucky to be able to call around this table people who, because of their personal and academic interests, are somewhat representative of great monotheistic confessions. The Catholic Church, represented by a cardinal; the Islamic world, represented by an islamologist. Reformed Christianity is represented by a scholar who is a minister of the Anglican Church, and we also have an Egyptologist who will perhaps talk to us about the relationship between Egyptian religion and monotheistic religions. The first speaker is Cardinal Cottier, who is from Geneva. He entered the Dominican order in 1945, was ordained in 1951 and became a professor in Geneva. In 1989, he was elected secretary of the International Theological Committee, and in 1990 he became Pontifical Theologian. As Titular Archbishop of Tullia he was created cardinal by Pope John Paul II in 2003.

In this paper Ambassador Romano reflects on the principal changes that have occurred in the orientation of Italian foreign policy (the alliance with the USA, relations with Europe, Russia, the Balkans, the Middle East) over the past decade, assessing and evaluating the effectiveness of the innovations made during the Berlusconi governments.

Thirty-seven basidiomycetous yeasts belonging to 30 species of seven genera were grown on media containing l-cysteine or l-methionine as sole nitrogen sources with the objective of evaluating volatile organic sulfur compound (VOSC) production. The headspace of yeast cultures was analyzed by the solid-phase microextraction (SPME) sampling method, and volatile compounds were quantified and identified by GC-MS techniques. Ten strains assimilating L-methionine produced the following VOSCs: 3-(methylthio)-1-propanol, methanethiol, S-methyl thioacetate, dimethyl disulfide, dimethyl trisulfide, allyl methyl sulphide and 4,5-dihydro-3(2H)-thiophenone. Production was <1 mgl(-1) except for 3-(methylthio)-1-propanol of which between 40 and 400 mgl(-1) was synthesized. Higher alcohols (isobutyl alcohol, isoamyl alcohol and active amyl alcohol) and esters (ethyl acetate, ethyl propionate, n-propyl acetate, isobutyl acetate, n-propyl propionate, n-butyl acetate, isoamyl acetate, amyl acetate, isoamyl propionate, amyl propionate and 2-phenylmethyl acetate) were also sporadically produced. This is the first report of VOSCs production by basidiomycetous yeasts. Consequently, basidiomycetous yeasts may be considered an interesting new group of microbial VOSCs producers for the flavor industry.

A 51-year-old native of Rio de Janeiro presented with bilateral synchronous Paget's sarcomas in the tibiae, which developed in the upper right tibia and in the distal third of the left tibia. There were no other areas of Paget's disease. The largest tumor spread to the right inguinal nodes and also soft tissue. The tumor in the left tibia spread dramatically in the soft tissues up the leg and only involved the medullary cavity in its inferior portion. The patient died, but there was no autopsy. Comments are made about the prevalence of Paget's disease in Rio de Janeiro.

A bulky tumor of the first lumbar vertebra is described. The case is the 21st to be reported. The tumor resembled an aneurysmal bone cyst radiologically. It was resected without incident. The previously reported cases are reviewed and the literature discussed.

Après des rapports italo-yougoslaves difficiles de 1918 à la Seconde Guerre mondiale, l'Italie établit, par les accords d'Osimo de 1975, des relations privilégiées avec le régime de Belgrade. D'où les efforts italiens en 1991 pour empêcher, autant que possible, la désagrégation de la Yougoslavie. En ce qui concerne l'Europe du Danube et des Balkans, le gouvernement italien a essayé de mettre sur pied, après les événements de 1989, une association politique et économique avec les pays de la région (Pologne, Tchécoslovaquie, Hongrie, Autriche, Yougoslavie) visant à leur faciliter l'accès à la Communauté européenne. En dépit de l'éclatement de l'État yougoslave, l'Italie continue à poursuivre ce but.

Sergio Romano, La politica estera dei partiti e la politica estera degli Stati, p. 485-492. Pour étudier le thème proposé il faudrait prendre en considération toutes les associations formelles ou informelles qui rassemblent à un niveau international des partis, des mouvements et des groupes de pression. Comme dans le cas de l'Association internationale des travailleurs, ces associations précèdent souvent la constitution des partis politiques qui se reconnaisent dans leur principes. Nous devons prêter une attention particulière aux Internationales socialistes et communistes car elles développent assez rapidement une « diplomatie de la révolution ». La crise du socialisme à la veille de la première guerre mondiale se traduit naturellement par la crise de l'Internationale, mais la naissance de l'État soviétique nous amènera à nous inter- (v. au verso) roger sur les contradictions existant souvent entre la «diplomatie de la révolution» et la diplomatie de l'État qui en assure la direction. Il n'y a pas qu'une diplomatie des Internationales contre les États. Il peut y avoir aussi une diplomatie coordonnée des États contre les Internationales. Il y a là un autre sujet pour nos réflexions.

Previous articleNext article No AccessBook ReviewsIn Stalin's Shadow: Angelo Tasca and the Crisis of the Left in Italy and France, 1910-1945. Alexander J. De Grand Sergio RomanoSergio Romano Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Modern History Volume 60, Number 2Jun., 1988 Article DOIhttps://doi.org/10.1086/600365 Views: 3Total views on this site Copyright 1988 The University of ChicagoPDF download Crossref reports no articles citing this article.