2,315 research outputs found
The dynamics of innovation through the expansion in the adjacent possible
No full textThe experience of something new is part of our daily life. At different scales, innovation is also a crucial feature of many biological, technological and social systems. Recently, large databases witnessing human activities allowed the observation that novelties —such as the individual process of listening a song for the first time— and innovation processes —such as the fixation of new genes in a population of bacteria— share striking statistical regularities. We here indicate the expansion into the adjacent possible as a very general and powerful mechanism
able to explain such regularities. Further, we will identify statistical signatures of the presence of the expansion into the adjacent possible in the analyzed datasets, and we will show that our modeling scheme is able to predict remarkably well these observations
A complex system approach to language evolution. The case of regular versus irregular verbs in English
No full textRegularities in natural language systems, despite their cognitive advantages in terms of storage and learnability, often coexist with exceptions, raising the question of whether and why irregularities survive. We offer a complex system perspective on this issue, focusing on the irregular past tense forms in English. Two separate processes affect the overall regularity: new verbs constantly entering the vocabulary in the regular form at low frequency, and transitions in both directions (from irregular to regular and vice-versa) occurring in a narrow frequency range. The introduction of new verbs leads to an increase in regular types, that, entering at low frequencies, have a small impact on the perceived irregularity in terms of tokens. The frequency of usage acts as a control parameter, the majority of verbs types being fully-regular(irregular) at low(high) frequencies, with no evidence of irregularity facing extinction. Very few verbs types in an intermediate frequency region exhibit both regular and irregular forms at the same time, suggesting that the coexistence is unstable. The observed pattern of usage showing an abrupt change in response to small variations of the control parameter only appears in agent-based models provided that the word state is non-binary. By introducing this key ingredient, high-frequency irregular past-tense can survive the tendency to regularize over time, as observed in natural languages
Opinion Dynamics: Models, Extensions and External Effects
No full textRecently, social phenomena have received a lot of attention not only from social scientists, but also from physicists, mathematicians and computer scientists, in the emerging interdisciplinary field of complex system science. Opinion dynamics is one of the processes studied, since opinions are the drivers of human behaviour, and play a crucial role in many global challenges that our complex world and societies are facing: global financial crises, global pandemics, growth of cities, urbanisation and migration patterns, and last but not least important, climate change and environmental sustainability and protection. Opinion formation is a complex process affected by the interplay of different elements, including the individual predisposition, the influence of positive and negative peer interaction (social networks playing a crucial role in this respect), the information each individual is exposed to, and many others. Several models inspired from those in use in physics have been developed to encompass many of these elements, and to allow for the identification of the mechanisms involved in the opinion formation process and the understanding of their role, with the practical aim of simulating opinion formation and spreading under various conditions. These modelling schemes range from binary simple models such as the voter model, to multi-dimensional continuous approaches. Here, we provide a review of recent methods, focusing on models employing both peer interaction and external information, and emphasising the role that less studied mechanisms, such as disagreement, has in driving the opinion dynamics. Due to the important role that external information (mainly in the form of mass media broadcast) can have in enhancing awareness of social issues, a special emphasis will be devoted to study different forms it can take, investigating their effectiveness in driving the opinion formation at the population level. The review shows that, although a large number of approaches exist, some mechanisms such as the effect of multiple external information sources could largely benefit from further studies. Additionally, model validation with real data, which are starting to become available, is still largely lacking and should in our opinion be the main ambition of future investigations
Data-compression approach to authorship attribution
No full textAuthorship attribution is a fascinating field at the crossroad between linguistics and information science. Its relevance goes much beyond the specific predictions that different tools can make about authors whose identity is uncertain or hidden behind known “noms de plume”. Correctly spotting the unknown author of a text is far from reflecting a “keyhole” attitude, representing instead the tip of an iceberg whose main body is made of solid tools and algorithms able to extract syntactic, possibly semantic, information out of generic strings of characters. Here we follow a data- compression approach to authorship attribution through which we define a notion of similarity between generic strings of characters (in particular literary texts). We start by assessing the overall performance of our set of tools in performing authorship attribution both on the wide corpus adopted in this volume and on an extended corpus. We then concentrate on the well-known “affaire Ferrante” (originally treated by some of us back in 20061), confirming and strengthening our original claim that, within the corpus considered, Domenico Starnone is the most likely author behind Elena Ferrante. We stress again that, despite the strong hints pointing to Starnone, we cannot rule out the possibility that Ferrante’s signature could hide another author (or several authors) not included in the corpus. Specific analyses are still in order to shed light on this last point
In Silico Linguistics Comment on "Modeling the cultural evolution of language" by Luc Steels
No full text[No abstract available
Language Games. Comment on "Modeling language evolution: examples and predictions" by Tao Gon, Lan Shuai, Menghan Zhang
No full textLarge Scale Engagement Through Web-Gaming and Social Computations
No full textIn the last few years the Web has progressively acquired the status of an infrastructure for social computation that allows researchers to coordinate the cognitive abilities of human agents, so to steer the collective user activity towards predefined goals. This general trend is also triggering the adoption of web-games as an alternative laboratory to run experiments in the social sciences and whenever the contribution of human beings can be effectively used for research purposes. Web-games introduce a playful aspect in scientific experiments with the result of increasing participation of people and of keeping their attention steady in time. The aim of this chapter is to suggest a general purpose web-based platform scheme for web-gaming and social computation. This platform will simplify the realization of web-games and will act as a repository of different scientific experiments, thus realizing a sort of showcase that stimulates users’ curiosity and helps researchers in recruiting volunteers. A platform built by following these criteria has been developed within the EveryAware project, the Experimental Tribe (XTribe) platform, which is operational and ready to be used. Finally, a sample web-game hosted by the XTribe platform will be presented with the aim of reporting the results, in terms of participation and motivation, of two different player recruiting strategies
Spin glasses on Bethe lattices for large coordination number
No full textWe study spin glasses on random lattices with finite connectivity. In the infinite connectivity limit they reduce to the Sherrington Kirkpatrick model. In this paper we investigate the expansion
around the high connectivity limit. Within the replica symmetry breaking scheme at two steps, we
compute the free energy at the first order in the expansion in inverse powers of the average
connectivity (z), both for the fixed connectivity and for the fluctuating connectivity random
lattices. It is well known that the coefficient of the 1/z correction for the free energy is
divergent at low temperatures if computed in the one step approximation. We find that this annoying
divergence becomes much smaller if computed in the framework of the more accurate two steps
breaking. Comparing the temperature dependance of the coefficients of this divergence in the replica
symmetric, one step and two steps replica symmetry breaking, we conclude that this divergence is an
artefact due to the use of a finite number of steps of replica symmetry breaking. The 1/z
expansion is well defined also in the zero temperature limit
A minimal stochastic model for influenza evolution
No full textWe introduce and discuss a minimal individual based model for influenza dynamics. The model takes into account the effects of specific immunization against viral strains, but also infectivity randomness and the presence of a short lived strain-transcending immunity recently suggested in the literature. We show by simulations that the resulting model exhibits substitution of viral strains along the years, but that their divergence remains bounded. We also show that dropping any of these features results in a drastically different behaviour, leading either to the extinction of the disease, to the proliferation of the viral strains or to their divergence
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