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Geometric Structures of Information, edited by:Nielsen, Frank, Springer International Publishing, Cham, 2019. pp.69--103.
Exponential families and mixture families are parametric probability models that can be geometrically studied as smooth statistical manifolds with respect to any statistical divergence like the Kullback–Leibler (KL) divergence or the Hellinger divergence. When equipping a statistical manifold with the KL divergence, the induced manifold structure is dually flat, and the KL divergence between distributions amounts to an equivalent Bregman divergence on their corresponding parameters. In practice, the corresponding Bregman generators of mixture/exponential families require to perform definite integral calculus that can either be too time-consuming (for exponentially large discrete support case) or even do not admit closed-form formula (for continuous support case). In these cases, the dually flat construction remains theoretical and cannot be used by information-geometric algorithms. To bypass this problem, we consider performing stochastic Monte Carlo (MC) estimation of those integral-based mixture/exponential family Bregman generators. We show that, under natural assumptions, these MC generators are almost surely Bregman generators. We define a series of dually flat information geometries, termed Monte Carlo Information Geometries, that increasingly-finely approximate the untractable geometry. The advantage of this MCIG is that it allows a practical use of the Bregman algorithmic toolbox on a wide range of probability distribution families. We demonstrate our approach with a clustering task on a mixture family manifold. We then show how to generate MCIG for arbitrary separable statistical divergence between distributions belonging to a same parametric family of distributions.
CoRR, abs/1901.03634, 2019.
2018.
19th International Society for Music Information Retrieval Conference (ISMIR), 2018.
19th International Society for Music Information Retrieval Conference (ISMIR), 2018.
19th International Society for Music Information Retrieval Conference (ISMIR), 2018.
Journal of New Music Research, 2018.
Neural Computing and Applications, special issue on Deep Learning and Music, 2018.
Language Dynamics and Change, 2018.
The reconstruction of phylogenies of cultural artefacts represents an open problem that mixes theoretical and computational challenges. Existing bench- marks rely on simulated phylogenies, where hypotheses on the underlying evolutionary mechanisms are unavoidable, or in real data phylogenies, for which no true evolutionary history is known. Here we introduce a web-based game, Copystree, where users create phylogenies of manuscripts, through successive copying actions, in a fully monitored setup. While players enjoy the experience, Copystree allows to build artificial phylogenies whose evolutionary processes do not obey to any pre-defined theoretical mechanisms, being generated instead with the unpredictability of human creativity. We present the analysis of the data gathered during the first set of experiments and use the artificial phylogenies gathered for a first test of existing phylogenetic algorithms.
submitted to Journal of The Royal Society Interface, 2018.
Submitted to Entropy, 2018.
Submitted for publication, 2018.
European conference dedicated to the future use of ICT in the agri-food sector, bioresource and biomass sector (EFITA), Montpellier, France, July, 2017.
ICCV 2017 workshop on Computer Vision Problems in Plant Phenotyping, Venise, Italy, November, 2017.
The AAAI 2017 Spring Symposium on Computational Construction Grammar and Natural Language Understanding Technical Report, SS-17-02, Association for the Advancement of Artificial Intelligence, Stanford, 2017. pp.266--273.
Human language users are capable of proficiently learning new constructions and using a language for everyday communication even if they have only acquired a basic linguistic inventory. This paper argues that such robustness can best be achieved through a constructional processing model in which grammatical structures may emerge spontaneously as a side effect of how constructions are combined with each other. This claim is substantiated by a fully operational precision model for Basic English in Fluid Construction Grammar, which is available for online testing. The precision model is the first ever to incorporate key properties from construction grammar in a large-scale setting, such as argument structure constructions and the surface generalization hypothesis, and is therefore a milestone achievement in the field of construction grammar.
Proceedings of the 34th International Conference on Machine Learning, edited by:Doina Precup and Yee Whye Teh, 70, PMLR, International Convention Centre, Sydney, Australia, August, 2017. pp.1362--1371.
Proceedings of the 18th International Society for Music Information Retrieval Conference, ISMIR, Suzhou, China, October, 2017. pp.23-27.
2017 IEEE Symposium Series on Computational Intelligence (SSCI 2017), IEEE, 2017. pp.1--7.
CoRR, abs/1711.10436, August, 2017.
CoRR, abs/1709.00740, 2017.
PloS one, edited by:Public Library of Science, 12, 6, 2017. pp.e0179303.
The emergence of novelties and their rise and fall
in popularity is an ubiquitous phenomenon in human
activities. The coexistence of always popular
milestones with novel and sometimes ephemeral trends
pervades technological, scientific and artistic
production. By introducing suitable statistical
measures, we demonstrate that different systems of
human activities, i.e. the creation of hashtags in
Twitter, the interaction with online program code
repositories, the creation of texts and the
listening of songs on an on-line platform, exhibit
surprisingly similar properties. We then introduce
a general framework to explain those
regularities. We propose a simple mathematical model
based on the expansion into the adjacent possible,
that has been proven to be a very general and
powerful mechanism able to explain many of the
statistical patterns emerging in innovation
dynamics, to which we add two crucial elements. On
the one hand we quantify the idea that, while
exploring a conceptual or physical space, inertia
exists towards known already discovered elements. On
the other hand, we highlight the role of the
collective dynamics – where many users interact, in
a direct or indirect way in the emergence and
diffusion of novelties and innovations.
2017.
The study of the dynamics behind the emergence of
novelties and innovation is a relatively recent
field of study in complex systems, fostered by the
abundance of data about the creations and sharing of
artworks and about on-line activity in
general. Despite this recentness, many works have
been able to discover and characterise several
interesting statistical patterns related to the
emergence of new creative elements and a very
general mathematical framework describing the
collective process of discovering and sharing
novelties come out. However, still a lot has to be
discovered concerning the conditions, either
historical and social, fostering the emergence of
creative elements from a group of interacting
individuals. From a social perspective, many
hypotheses have been developed and tested
concerning the relations between individual like the
presence of ?weak ties? in social networks or the
?folding? of different social groups into a larger
one sharing a common goal. Complex Systems Science
has given little contributions to the
understanding of how the dynamics behind social
interactions contributes to foster the emergence of
creativity. This work of thesis is devoted to the
analysis of data collected during a collective
social experiment in which individuals were asked to
collaborate in the realisation of a set of LEGO
bricks sculptures. The participants to the
experiments were provided with particular RFID tags,
developed in the framework of the SOCIOPATTERNS
project, that enabled a quite precise mapping of the
social interactions occurring during their activity
within the experiment. The interaction with the LEGO
Sculptures were similarly mapped by means of other
RFID tags placed around the sculptures, and their
growth in volume has been recorded with the aid of
infra-red depth sensors. The RFID sensors allowed
for a reconstruction of the dynamical network of
social interactions between the participants in the
experiment. We looked for correlations between the
evolving structure of this social net- work and the
growing patterns of the sculptures, spotting the
local social structures more prone for a rapid
growth of the volume in small amounts of times and
in long term periods. In this way, we were able to
identify the social patterns more fruitful in terms
of ?local consensus? around the development of the
collective artwork, indicating a shared vision
around the actions to be performed on it. Moreover,
we were able to identify how the presence of
‘influential individuals’ characterised by means of
information spreading models favoured the growth of
the sculptures in the long-term. The novelty behind
the proposed approach could contribute to shed light
on the phenomena related to creativity and could be
useful in conceiving and designing new collecting
creativity experiments.
Cognition, 159, Elsevier, 2017. pp.25--32.
Rules are an efficient feature of natural languages
which allow speakers to use a finite set of
instructions to generate a virtually infinite set of
utterances. Yet, for many regular rules, there are
irregular exceptions. There has been lively debate
in cognitive science about how individual learners
acquire rules and exceptions; for example, how they
learn the past tense of preach is preached, but for
teach it is taught. However, for most population or
language-level models of language structure,
particularly from the perspective of language
evolution, the goal has generally been to examine
how languages evolve stable structure, and neglects
the fact that in many cases, languages exhibit
exceptions to structural rules. We examine the
dynamics of regularity and irregularity across a
population of interacting agents to investigate how,
for example, the irregular teach coexists beside the
regular preach in a dynamic language system. Models
show that in the absence of individual biases
towards either regularity or irregularity, the
outcome of a system is determined entirely by the
initial condition. On the other hand, in the
presence of individual biases, rule systems exhibit
frequency dependent patterns in regularity
reminiscent of patterns found in natural
language. We implement individual biases towards
regularity in two ways: through ?child? agents who
have a preference to generalise using the regular
form, and through a memory constraint wherein an
agent can only remember an irregular form for a
finite time period. We provide theoretical arguments
for the prediction of a critical frequency below
which irregularity cannot persist in terms of the
duration of the finite time period which constrains
agent memory. Further, within our framework we also
find stable irregularity, arguably a feature of most
natural languages not accounted for in many other
cultural models of language structure.
Royal Society Open Science, 4, 7, The Royal Society, 2017.
PLOS ONE, 12, 2, Public Library of Science, 2017. pp.e0170746.
Scientific Reports, 7, 1, Nature Publishing Group, 2017. pp.9172.
Human Computation Journal, 2016.
Proceedings of the 2nd AES Workshop on Intelligent Music Production (WIMP2016), London (UK), September, 2016.
September, 2016.
AAAI, France, February, 2016.
November, 2016.
November, 2016.
December, 2016.
October, 2016.
Frontiers in Psychology, 7, 474, 2016.
Paris, France, June, 2016.
4, Language Science Press, Berlin, 2016.
Children's Creative Music Making: Adventures with Reflexive Interactive Technology, Routledge, 2016.
Belgian Journal of Linguistics, 30, 1, 2016. pp.1--13.
After several decades in scientific purgatory, language evolution has reclaimed its place as one of the most important branches in linguistics. This renewed interest is accompanied by powerful new methods for making empirical observations. At the same time, construction grammar is increasingly embraced in all areas of linguistics as a fruitful way of making sense of all these new data, and it has enthused formal and computational linguists, who have developed sophisticated tools for exploring issues in language processing and learning. Separately, linguists and computational linguists are able to explain which changes take place in language and how these changes are possible. When working together, however, they can also address the question of why language evolves over time and how it emerged in the first place. This special issue therefore brings together key contributions from both fields to put evidence and methods from both perspectives on the table.
Creativity and Universality in Language, edited by:Degli Esposti, M. and Altmann, E. and Pachet, Fran{c{c}}ois, Springer, 2016.
Belgian Journal of Linguistics, 30, 1, 2016. pp.15--38.
Word order, argument structure and unbounded dependencies are among the most important topics in linguistics because they touch upon the core of the syntax-semantics interface. One question is whether ?marked? word order patterns, such as The man I talked to vs. I talked to the man, require special treatment by the grammar or not. Mainstream linguistics answers this question affirmatively: in the marked order, some mechanism is necessary for ?extracting? the man from its original argument position, and a special placement rule (e.g. topicalization) is needed for putting the constituent in clause-preceding position. This paper takes an opposing view and argues that such formal complexity is only required for analyses that are based on syntactic trees. A tree is a rigid data structure that only allows information to be shared between local nodes, hence it is inadequate for non-local dependencies and can only allow restricted word order variations. A construction, on the other hand, offers a more powerful representation device that allows word order variations ? even unbounded dependencies ? to be analyzed as the side-effect of how language users combine the same rules in different ways in order to satisfy their communicative needs. This claim is substantiated through a computational implementation of English argument structure constructions in Fluid Construction Grammar that can handle both comprehension and formulation.
Journ{'e}es Francophones sur les R{'e}seaux Bay{'e}siens et les Mod{`e}les Graphiques Probabilistes, Clermont-Ferrand, France, June, 2016.
Proceedings of COLING 2016, the 26th International Conference on Computational Linguistics: Technical Papers, The COLING 2016 Organizing Committee, Osaka, 2016. pp.1646--1656.
Human languages have multiple strategies that allow us to discriminate objects in a vast variety of contexts. Colours have been extensively studied from this point of view. In particular, previous research in artificial language evolution has shown how artificial languages may emerge based on specific strategies to distinguish colours. Still, it has not been shown how several strategies of diverse complexity can be autonomously managed by artificial agents . We propose an intrinsic motivation system that allows agents in a population to create a shared artificial language and progressively increase its expressive power. Our results show that with such a system agents successfully regulate their language development, which indicates a relation between population size and consistency in the emergent communicative systems.
Proceedings of the 22nd International Conference on Principles and Practice of Constraint Programming - CP, Springer, Toulouse, France, September, 2016.
Nederlandse Taalkunde, 21, 1, March, 2016. pp.93--119.
Long-distance dependencies belong to the most controversial challenges in linguistics. These patterns seem to contain constituents that have left their original position in a sentence and that have landed in a different place. A typical example is the relative clause the person I have talked to yesterday, in which the direct object (the person) is not situated in an argument position following the verb, but instead is located at the beginning of the utterance. Upon closer inspection, however, all problems related to long-distance dependencies can be reduced to the limits of phrase structural analyses. A phrase structure tree is a rigid data structure in which information is shared between local nodes. These analyses therefore need to resort to more complex formal machinery in order to overcome this locality constraint, such as using transformations or positing filler-gap constructions. However, there exists a more intuitive alternative within the tradition of cognitive-functional linguistics in which long-distance dependencies do not require special treatment. Instead, these patterns are simply the side effect of how grammatical constructions combine with each other in order to satisfy the communicative needs of language users. Through a computational implementation in Fluid Construction Grammar, this article demonstrates that it is perfectly feasible to formalize this alternative in a model that is capable of both formulating and comprehending utterances.
Proceedings of the 22nd International Conference on Principles and Practice of Constraint Programming - CP, Toulouse, France, September, 2016.
Nederlandse Taalkunde, 21, 1, March, 2016. pp.137--150.
Music Perception, 33, 5, June, 2016.
2016.
The recent spread of social networks and ICT systems
has allowed for a huge availability of data on
social phenomena and collective behaviour. This has
induced a deep change in social dynamics field, that
moved from an essentially theoretical approach to a
strongly data driven one. In such framework, the
present work aims at exploring the collaboration
dynamics and the organisational structures within
the GitHub platform. Moreover, the purpose is using
success and popularity as feedbacks to check whether
some particular structures exist that are associated
with more efficiency, better results and
subsequently more innovative features in the
development of the code. GitHub is based on the Git
revision control system and is currently the most
important platform for open source coding, counting
millions of repositories and active users. Moreover,
the complete timeline of GitHub activity is publicly
accessible on the GitHub Archive website. GitHub is
therefore a particularly suitable system to observe
and analyse collective social behaviours and
collaborative dynamics. The collaboration among
users fosters an uninterrupted flow of new ideas
which actualise in many different events such as the
creation of new projects and updating of existing
ones through code modifications. The analysis
required a preliminary selection of the data
downloaded from GitHub Archive in order to create a
database containing all the necessary information
about projects activity. The analysis carried out on
this database was mostly inspired by previous
research on innovation dynamics in the framework of
complex systems. Every project was mapped in a
network structure in order to observe dynamically
the development and the modifications of the
code. Some metrics were defined that could estimate
the collaboration degree among users and the
organization of the workload within the developing
branches. Other metrics were chosen in order to
evaluate both the success and the popularity reached
by a project and its potential
innovation. Correlation analysis between the metrics
and the indexes above mentioned allow for some
evaluations about the interdependence between
attention received and structural features of the
projects. This thesis work follows up several
quantitative analyses on GitHub presented in
literature and proposes a new visualisation of
internal structures and collaborative dynamics
within GitHub projects. Moreover, identifying
successful patterns could help in highlighting the
most influential and pioneering projects and
encouraging their development.
submitted to ICCC 2016 - The Seventh International Conference on Computational Creativity, Proceedings of the Seventh International Conference on Computational Creativity, June 2016, 2016.
It is common opinion that many innovations are
triggered by serendipity whose notion is associated
with fortuitous events leading to unintended
consequences. One might argue that this
interpretation is due to the poor understanding of
the dynamics of innovations. Very little is known,
in fact, about how innovations proceed and samples
the space of potential novelties. This space is
usually referred to as the adjacent possible, a
concept originally introduced in the study of
biological systems to indicate the set of
possibilities that are one step away from what
actually exists. In this paper we focus on the
problem of defining the adjacent possible space, and
analyzing its dynamics, for a particular system,
namely the cultural system of the network of movies.
We synthesized to this end the graph emerging from
the Internet Movies Database (IMDb) and looked at
the static and dynamical properties of this
network. We deal, in particular, with the subtle
mechanism of the adjacent possible by measuring the
expansion and the coverage of this elusive space
during the global evolution of the system. Finally,
we introduce the concept of adjacent possibilities
at the level of single node and try to elucidate its
nature by looking at the correlations with
topological and user annotation metrics.
COMPLEXIS 2016, 1st International Conference on Complex Information Systems, Rome, 22-24 April 2016, 2016.
The dynamics of political votes has been widely
studied, both for its practical interest and as a
paradigm of the dynamics of mass opinions and
collective phenomena, where theoretical predictions
can be easily tested. However, the vote outcome is
often influenced by many factors beyond the bare
opinion on the candidate, and in most cases it is
bound to a single preference. The voter perception
of the political space is still to be elucidated. We
here propose a web experiment (laPENSOcos`ı) where
we explicitly investigate participants’ opinions on
political entities (parties, coalitions, individual
candidates) of the Italian political scene. As a
main result, we show that the political perception
follows a Weber-Fechner-like law, i.e., when ranking
political entities according to the user expressed
preferences, the perceived distance of the user from
a given entity scales as the logarithm of this
rank.
The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11), edited by:S.G. Roberts and C. Cuskley and L. McCrohon and L. Barcel'o-Coblijn and O. Feh'er and T. Verhoef, 2016.
Rules are an efficient feature of natural languages
which allow speakers to use a finite set of
instructions to generate a virtually infinite set of
utterances. Yet, for many regular rules, there are
irregular exceptions. There has been lively debate
in cognitive science about how individual learners
acquire rules and exceptions; for example, how they
learn the past tense of preach is preached, but for
teach it is taught. In this paper, we take a
different perspective, examining the dynamics of
regularity and irregularity across a population of
interacting agents to investigate how inflectional
rules are applied to verbs. We show that in the
absence of biases towards either regularity or
irregularity, the outcome is determined by the
initial condition, irrespective of the frequency of
usage of the given lemma. On the other hand, in
presence of biases, rule systems exhibit frequency
dependent patterns in regularity reminiscent of
patterns in natural language corpora. We examine the
case where individuals are biased towards linguistic
regularity in two ways: either as child learners, or
through a memory constraint wherein irregular forms
can only be remembered by an individual agent for a
finite time period. We provide theoretical arguments
for the prediction of a critical frequency below
which irregularity cannot persist in terms of the
duration of the finite time period which constrains
agent memory.
The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11), edited by:S.G. Roberts and C. Cuskley and L. McCrohon and L. Barcel'o-Coblijn and O. Feh'er and T. Verhoef, 2016.
Studies in literature and narrative have begun to
argue more forcefully for considering human
evolution as central to understanding stories and
storytelling more generally (Sugiyama, 2001;
Hernadi, 2002). However, empirical studies in
language evolution have focused primarily on
language structure or the language faculty, leaving
the evolution of stories largely unexplored
(although see Von Heiseler, 2014). Stories are
unique products of human culture enabled principally
by human language. Given this, the dynamics of
creativity in stories, and the traits which make
successful stories, are of crucial interest to
understanding the evolution of language in the
context of human evolution more broadly. The current
work aims to illuminate how stories emerge, evolve,
and change in the context of a collaborative
cultural effort. We present results from a novel
experimental paradigm centered around a story game
where players write short continuations (between 60
and 120 characters) of existing stories. These
continuations then become open to other players to
continue in turn. Stories are subject to player
selection, allowing for variation and speciation of
the resulting narratives, and evolve as a result of
collaborative effort between players. The game
starts with a seed of over 60 potential stories, and
players choose which stories to continue, providing
a player-driven story selection mechanism. In this
way, stories which are creative, intriguing, and
open ended spawn more stories, and eventually lead
to longer story paths as play continues. The game
also introduces further limitations by constraining
a players’�� view of the story path: players have
access only to a story and its parent, meaning
knowledge of the existing narrative is limited. We
present data from hundreds of players and stories,
creating large story trees which explore the space
of different possible narratives which grow out of a
confined set of starting points. This data allows us
to investigate several aspects of the growing story
trees to illuminate not only what makes a story
successful, but how creative stories trigger new
stories, and what makes individual storytellers
successful. Given the selection mechanism central to
game play, we identify the most successful stories
by their number of offspring. Particularly
successful storytellers emerge measured both by how
many children their stories have spawned, and also
how long their story path extends. We also show that
coherent stories often emerge, despite the fact that
they are authored by several different players, and
any given player only sees a limited snapshot of the
story path. We contextualise the results of the game
and connect it to language evolution in two
ways. First, we look for detectable triggers of
innovation and creativity within the story trees,
and identify these as expanding the adjacent
possible (e.g., new adaptations open the space of
other possible adaptations in the future; Tria,
Loreto, Servedio, & Strogatz, 2014). We argue that
this concept can be extended to stories, using
evidence from the game bolstered by evidence from
more traditional literature (the Gutenberg
Corpus). Second, we frame the results in terms of
recurring themes found in storytelling
cross-culturally (Tehrani, 2013). We suggest that
the most successful triggers of innovation in
stories combine original novelty and a firm
grounding in existing recurring story frameworks in
human culture. This indicates that much like other
cultural and biological systems, stories are subject
to competing pressures for stability and
conservation on the one hand, and innovation and
novelty on the other.
The Evolution of Language: Proceedings of the 11th International Conference (EVOLANGX11), edited by:S.G. Roberts and C. Cuskley and L. McCrohon and L. Barcel'o-Coblijn and O. Feh'er and T. Verhoef, 2016.
Creole languages offer an invaluable opportunity to
study the processes leading to the emergence and
evolution of Language, thanks to the short –
typically a few generations – and reasonably well
defined time-scales involved in their
emergence. Another well-known case of a very fast
emergence of a Language, though referring to a much
smaller population size and different ecological
conditions, is that of the Nicaraguan Sign
Language. What these two phenomena have in common is
that in both cases what is emerging is a contact
language, i.e., a language born out of the
non-trivial interaction of two (or more) parent
languages. This is a typical case of what is known
in biology as horizontal transmission. In many
well-documented cases, creoles emerged in large
segregated sugarcane or rice plantations on which
the slave labourers were the overwhelming
majority. Lacking a common substrate language,
slaves were naturally brought to shift to the
economically and politically dominant European
language (often referred to as the lexifier) to
bootstrap an effective communication system among
themselves. Here, we focus on the emergence of
creole languages originated in the contacts of
European colonists and slaves during the 17th and
18th centuries in exogenous plantation colonies of
especially the Atlantic and Indian Ocean, where
detailed census data are available. Those for
several States of USA can be found at
http://www.census.gov/history, while for Central
America and the Caribbean can be found at
http://www.jamaicanfamilysearch.com/Samples/1790al11.htm. Without
entering in the details of the creole formation at a
fine-grained linguistic level, we aim at uncovering
some of the general mechanisms that determine the
emergence of contact languages, and that
successfully apply to the case of creole formation.
Creativity and universality in language, Springer, 2016. pp.59--83.
Topics in cognitive science, 8, 2, Wiley Online Library, 2016. pp.469--480.
The complex organization of syntax in hierarchical
structures is one of the core design features of
human language. Duality of patterning refers for
instance to the organization of the meaningful
elements in a language at two distinct levels: a
combinatorial level where meaningless forms are
combined into meaningful forms and a compositional
level where meaningful forms are composed into
larger lexical units. The question remains wide open
regarding how such a structure could have
emerged. Furthermore a clear mathematical framework
to quantify this phenomenon is still lacking. The
aim of this paper is that of addressing these two
aspects in a self-consistent way. First, we
introduce suitable measures to quantify the level of
combinatoriality and compositionality in a language,
and present a framework to estimate these
observables in human natural languages. Second, we
show that the theoretical predictions of a
multi-agents modeling scheme, namely the Blending
Game, are in surprisingly good agreement with
empirical data. In the Blending Game a population of
individuals plays language games aiming at success
in communication. It is remarkable that the two
sides of duality of patterning emerge simultaneously
as a consequence of a pure cultural dynamics in a
simulated environment that contains meaningful
relations, provided a simple constraint on message
transmission fidelity is also considered.
COMPLEXIS 2016, 1st International Conference on Complex Information Systems, Rome, 22-24 April 2016, 2016.
The understanding and the characterisation of
individual mobility patterns in urban environments
is important in order to improve liveability and
planning of big cities. In relatively recent times,
the availability of data regarding human movements
have fostered the emergence of a new branch of
social studies, with the aim to unveil and study
those patterns thanks to data collected by means of
geolocalisation technologies. In this paper we
analyse a large dataset of GPS tracks of cars
collected in Rome (Italy). Dividing the drivers in
classes according to the number of trips they
perform in a day, we show that the sequence of the
travelled space connecting two consecutive stops
shows a precise behaviour so that the shortest trips
are performed at the middle of the sequence, when
the longest occur at the beginning and at the end
when drivers head back home. We show that this
behaviour is consistent with the idea of an
optimisation process in which the total travel time
is minimised, under the effect of spatial
constraints so that the starting points is on the
border of the space in which the dynamics takes
place.
1, WSPC, 2016.
Coping with the complexities of the social world in
the 21st century requires deeper quantitative and
predictive understanding. Forty-three
internationally acclaimed scientists and thinkers
share their vision for complexity science in the
next decade in this invaluable book. Topics cover
how complexity and big data science could help
society to tackle the great challenges ahead, and
how the newly established Complexity Science Hub
Vienna might be a facilitator on this path.
1st International Conference on Technologies for Music Notation and Representation (TENOR 2015), Paris (France), May, 2015.
Workshop AI and Feedback, 24th International Joint Conference on Artificial Intelligence (IJCAI 2015), Buenos Aires, Argentina, July, 2015.
Workshop AI and Feedback, 24th International Joint Conference on Artificial Intelligence (IJCAI 2015), Buenos Aires (Argentina), July, 2015.
Multidisciplinary Contributions to the Science of Creative Thinking (Creativity in the Twenty First Century), edited by:Corazza, G.E., and Agnoli, S., Springer, September, 2015.
24th International Joint Conference on Artificial Intelligence (IJCAI 2015), Buenos Aires (Argentina), July, 2015. pp.4136-4137.
24th International Joint Conference on Artificial Intelligence (IJCAI 2015), Buenos Aires (Argentina), July, 2015.
September, 2015.
Proceedings of Complex Systems Digital Campus '15 (CS-DC'15), Phoenix, Arizona (USA), Sept. 28-Oct. 2, 2015.
24th International Joint Conference on Artificial Intelligence (IJCAI 2015), Buenos Aires (Argentina), July, 2015. pp.4140-4142.
Proceedings of the European Conference on Artificial Life 2015, edited by:Andrews, Paul and Caves, Leo and Doursat, Ren'{e} and Hickinbotham, Simon and Polack, Fiona and Stepney, Susan and Taylor, Tim, MIT Press, Cambridge MA, 2015. pp.571--578.
Natural languages enable humans to engage in highly complex social and conversational interactions with each other. Alife approaches to the origins and emergence of language typically manage this complexity by carefully staging the learning paths that embodied artificial agents need to follow in order to bootstrap their own communication system from scratch. This paper investigates how these scaffolds introduced by the experimenter can be removed by allowing agents to autonomously set their own challenges when they are driven by intrinsic motivation and have the capacity to self-assess their own skills at achieving their communicative goals. The results suggest that intrinsic motivation not only allows agents to spontaneously develop their own learning paths, but also that they are able to make faster transitions from one learning phase to the next.
Proceedings of the EuroAsianPacific Joint Conference on Cognitive Science, 2015. pp.187-192.
Proceedings of the EuroAsianPacific Joint Conference on Cognitive Science, edited by:Airenti, Gabriella and Bara, Bruni G. and Sandini, Giulio, University of Torino, Turin, 2015. pp.668--673.
Sign languages (SL) require a fundamental rethinking of many basic assumptions about human language processing because instead of using linear speech, sign languages coarticulate facial expressions, shoulder and hand movements, eye gaze and usage of a three-dimensional space. SL researchers have therefore advocated SL-specific approaches that do not start from the biases of models that were originally developed for vocal languages. Unfortunately, there are currently no processing models that adequately achieve both language comprehension and formulation, and the SL-specific developments run the risk of becoming alienated from other linguistic research. This paper explores the hypothesis that a construction grammar architecture offers a solution to these problems because constructions are able to simultaneously access and manipulate information coming from many different sources. This claim is illustrated by a proof-of-concept implementation of a basic grammar for French Sign Language in Fluid Construction Grammar.
Cognitive Linguistics, 26, 4, 2015. pp.613--632.
One of the most salient hallmarks of construction grammar is its approach to argument structure and coercion: rather than positing many different verb senses in the lexicon, the same lexical construction may freely interact with multiple argument structure constructions. This view has however been criticized from within the construction grammar movement for leading to overgeneration. This paper argues that this criticism falls flat for two reasons: (1) lexicalism, which is the alternative solution proposed by the critics, has already been proven to overgenerate itself, and (2) the argument of overgeneration becomes void if grammar is implemented as a problem-solving model rather than as a generative competence model; a claim that the paper substantiates through a computational operationalization of argument structure and coercion in Fluid Construction Grammar. The paper thus shows that the current debate on argument structure is hiding a much more fundamental rift between practitioners of construction grammar that touches upon the role of grammar itself.
Proceedings of the 16th ISMIR Conference, Malaga, Spain, 2015.
Geometric Science of Information, edited by:Nielsen, Frank and Barbaresco, Fr{'e}d{'e}ric, Springer International Publishing, Cham, 2015. pp.586--594.
Phys. Rev. E, 91, American Physical Society, 2015. pp.012808.
Empirical evidence shows that the rate of irregular
usage of English verbs exhibits discontinuity as a
function of their frequency: the most frequent verbs
tend to be totally irregular. We aim to
qualitatively understand the origin of this feature
by studying simple agent-based models of language
dynamics, where each agent adopts an inflectional
state for a verb and may change it upon interaction
with other agents. At the same time, agents are
replaced at some rate by new agents adopting the
regular form. In models with only two inflectional
states (regular and irregular), we observe that
either all verbs regularise irrespective of their
frequency, or a continuous transition occurs between
a low-frequency state, where the lemma becomes fully
regular, and a high-frequency one, where both forms
coexist. Introducing a third (mixed) state, wherein
agents may use either form, we find that a third,
qualitatively different behaviour may emerge,
namely, a discontinuous transition in frequency. We
introduce and solve analytically a very general
class of three-state models that allows us to fully
understand these behaviours in a unified
framework. Realistic sets of interaction rules,
including the well-known naming game (NG) model,
result in a discontinuous transition, in agreement
with recent empirical findings. We also point out
that the distinction between speaker and hearer in
the interaction has no effect on the collective
behaviour. The results for the general three-state
model, although discussed in terms of language
dynamics, are widely applicable.
Journal of Memory and Language, 84, 2015. pp.205 - 223.
Several recent theories have suggested that an
increase in the number of non-native speakers in a
language can lead to changes in morphological
rules. We examine this experimentally by contrasting
the performance of native and non-native English
speakers in a simple Wug-task, showing that
non-native speakers are significantly more likely to
provide non -ed (i.e., irregular) past-tense forms
for novel verbs than native speakers. Both groups
are sensitive to sound similarities between new
words and existing words (i.e., are more likely to
provide irregular forms for novel words which sound
similar to existing irregulars). Among both natives
and non-natives, irregularizations are non-random;
that is, rather than presenting as truly irregular
inflectional strategies, they follow identifiable
sub-rules present in the highly frequent set of
irregular English verbs. Our results shed new light
on how native and non-native learners can affect
language structure.
PloS one, 10, 12, Public Library of Science, 2015. pp.e0143799.
The comprehension of vehicular traffic in urban
environments is crucial to achieve a good management
of the complex processes arising from people
collective motion. Even allowing for the great
complexity of human beings, human behavior turns out
to be subject to strong constraints—physical,
environmental, social, economic—that induce the
emergence of common patterns. The observation and
understanding of those patterns is key to setup
effective strategies to optimize the quality of life
in cities while not frustrating the natural need for
mobility. In this paper we focus on vehicular
mobility with the aim to reveal the underlying
patterns and uncover the human strategies
determining them. To this end we analyze a large
dataset of GPS vehicles tracks collected in the Rome
(Italy) district during a month. We demonstrate the
existence of a local optimization of travel times
that vehicle drivers perform while choosing their
journey. This finding is mirrored by two additional
important facts, i.e., the observation that the
average vehicle velocity increases by increasing the
travel length and the emergence of a universal
scaling law for the distribution of travel times at
fixed traveled length. A simple modeling scheme
confirms this scenario opening the way to further
predictions.
PloS one, 10, 5, Public Library of Science, 2015. pp.e0125019.
Language universals have long been attributed to an
innate Universal Grammar. An alternative explanation
states that linguistic universals emerged
independently in every language in response to
shared cognitive or perceptual biases. A
computational model has recently shown how this
could be the case, focusing on the paradigmatic
example of the universal properties of colour naming
patterns, and producing results in quantitative
agreement with the experimental data. Here we
investigate the role of an individual perceptual
bias in the framework of the model. We study how,
and to what extent, the structure of the bias
influences the corresponding linguistic universal
patterns. We show that the cultural history of a
group of speakers introduces population-specific
constraints that act against the pressure for
uniformity arising from the individual bias, and we
clarify the interplay between these two forces
PloS one, 10, 5, Public Library of Science, 2015. pp.e0125546.
Scientific reports, 5, Nature Publishing Group, 2015. pp.10286.
ICML Workshop on Constructive Machine Learning, 2015.
We introduce a model for music generation where
melodies are seen as a network of interacting
notes. Starting from the principle of maximum
entropy we assign to this network a probability
distribution, which is learned from an existing
musical corpus. We use this model to generate novel
musical sequences that mimic the style of the
corpus. Our main result is that this model can
reproduce high-order patterns despite having a
polynomial sample complexity. This is in contrast
with the more traditionally used Markov models that
have an exponential sample complexity.
PLoS ONE, 10, 4, Public Library of Science, 2015. pp.e0120771.
Contact languages are born out of the non-trivial
interaction of two (or more) parent
languages. Nowadays, the enhanced possibility of
mobility and communication allows for a strong
mixing of languages and cultures, thus raising the
issue of whether there are any pure languages or
cultures that are unaffected by contact with
others. As with bacteria or viruses in biological
evolution, the evolution of languages is marked by
horizontal transmission; but to date no reliable
quantitative tools to investigate these phenomena
have been available. An interesting and well
documented example of contact language is the
emergence of creole languages, which originated in
the contacts of European colonists and slaves during
the 17th and 18th centuries in exogenous plantation
colonies of especially the Atlantic and Indian
Ocean. Here, we focus on the emergence of creole
languages to demonstrate a dynamical process that
mimics the process of creole formation in American
and Caribbean plantation ecologies. Inspired by the
Naming Game (NG), our modeling scheme incorporates
demographic information about the colonial
population in the framework of a non-trivial
interaction network including three populations:
Europeans, Mulattos/Creoles, and Bozal slaves. We
show how this sole information makes it possible to
discriminate territories that produced modern
creoles from those that did not, with a surprising
accuracy. The generality of our approach provides
valuable insights for further studies on the
emergence of languages in contact ecologies as well
as to test specific hypotheses about the peopling
and the population structures of the relevant
territories. We submit that these tools could be
relevant to addressing problems related to contact
phenomena in many cultural domains: e.g., emergence
of dialects, language competition and hybridization,
globalization phenomena.
28th Conference on Artificial Intelligence (AAAI 2014), Quebec (Canada), July, 2014. pp. 2731--2737.
Journal of the Audio Engineering Society, 62, 10, October, 2014. pp.643--653.
Language and Cognition, 6, 02, Cambridge University Press, 2014. pp.242--270.
Long-distance dependencies are notoriously diffi cult to analyze in a formally explicit way because they involve constituents that seem to have been extracted from their canonical position in an utterance. The most widespread solution is to identify a GAP at an EXTRACTION SITE and to communicate information about that gap to its FILLER, as in What_FILLER did you see_GAP? This paper rejects the filler?gap solution and proposes a cognitive-functional alternative in which long-distance dependencies spontaneously emerge as a side eff ect of how grammatical constructions interact with each other for expressing diff erent conceptualizations. The proposal is supported by a computational implementation in Fluid Construction Grammar that works for both parsing and production.
The Evolution of Language (EVOLANG-X), edited by:Cartmill, E.A. and Roberts, S. and Lyn, H. and Cornish, H., World Scientific Press, Singapore, 2014. pp.334--341.
Computational experiments in cultural language evolution are important because they help to reveal the cognitive mechanisms and cultural processes that continuously shape and reshape the structure and knowledge of language. However, understanding the intricate relations between these mechanisms and processes can be a daunting challenge. This paper proposes to recruit the concept of fitness landscapes from evolutionary biology and computer science for visualizing the ?linguistic fitness? of particular language systems. Through a case study on the German paradigm of definite articles, the paper shows how such landscapes can shed a new and unexpected light on non-trivial cases of language evolution. More specifically, the case study falsifies the widespread assumption that the paradigm is the accidental by-product of linguistic erosion. Instead, it has evolved to optimize the cognitive and perceptual resources that language users employ for achieving successful communication.
PLoS ONE, 9, Public Library of Science, 2014.
Human languages are rule governed, but almost
invariably these rules have exceptions in the form
of irregularities. Since rules in language are
efficient and productive, the persistence of
irregularity is an anomaly. How does irregularity
linger in the face of internal (endogenous) and
external (exogenous) pressures to conform to a rule?
Here we address this problem by taking a detailed
look at simple past tense verbs in the Corpus of
Historical American English. The data show that the
language is open, with many new verbs entering. At
the same time, existing verbs might tend to
regularize or irregularize as a consequence of
internal dynamics, but overall, the amount of
irregularity sustained by the language stays roughly
constant over time. Despite continuous vocabulary
growth, and presumably, an attendant increase in
expressive power, there is no corresponding growth
in irregularity. We analyze the set of irregulars,
showing they may adhere to a set of minority rules,
allowing for increased stability of irregularity
over time. These findings contribute to the debate
on how language systems become rule governed, and
how and why they sustain exceptions to rules,
providing insight into the interplay between the
emergence and maintenance of rules and exceptions in
language.
Scientific reports, 4, Nature Publishing Group, 2014. pp.5890.
Journal of New Music Research, Special issue on Music and Machine Learning, 43, 3, 2014. pp.276--290.
5th International Conference on Computational Creativity (ICCC 2014), Ljubljiana (Slovenia), June, 2014. pp.100--107.
21st European Conference on Artificial Intelligence (ECAI 2014), Prague (Czech Republic), August, 2014. pp.1077--1078.
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics, Association for Computational Linguistics, Sofia, 2013. pp.127--132.
Fluid Construction Grammar (FCG) is an open-source computational grammar formalism that is becoming increasingly popular for studying the history and evolution of language. This demonstration shows how FCG can be used to operationalise the cultural processes and cognitive mechanisms that underly language evolution and change.
Constructions and Frames, 5, 2013. pp.88--116.
Construction Grammar has reached a stage of maturity where many researchers are looking for an explicit formal grounding of their work. Recently, there have been exciting developments to cater for this demand, most notably in Sign-Based Construction Grammar (SBCG) and Fluid Construction Grammar (FCG). Unfortunately, like playing a music instrument, the formalisms used by SBCG and FCG take time and effort to master, and linguists who are unfamiliar with them may not always appreciate the far-reaching theoretical consequences of adopting this or that approach. This paper undresses SBCG and FCG to their bare essentials, and offers a linguist-friendly comparison that looks at how both approaches define constructions, linguistic knowledge and language processing.
Language Dynamics and Change, 3, 2013. pp.105--132.
The German definite article paradigm, which is notorious for its case syncretism, is widely considered to be the accidental by-product of diachronic changes. This paper argues instead that the evolution of the paradigm has been motivated by the needs and constraints of language usage. This hypothesis is supported by experiments that compare the current paradigm to its Old High German ancestor (OHG; 900?1100ad) in terms of linguistic assessment criteria such as cue reliability, processing efficiency and ease of articulation. Such a comparison has been made possible by ?bringing back alive? the OHG system through a computational reconstruction
in the form of a processing model.The experiments demonstrate that syncretism has made the New High German system more efficient for processing, pronunciation and perception than its historical predecessor, without harming the language?s strength at disambiguating utterances.
Paris (France), July, 2013.
EUROPHYSICS LETTERS, 101, 2013.
The naming game (NG) describes the agreement
dynamics of a population of N agents interacting
locally in pairs leading to the emergence of a
shared vocabulary. This model has its relevance in
the novel fields of semiotic dynamics and
specifically to opinion formation and language
evolution. The application of this model ranges from
wireless sensor networks as spreading algorithms,
leader election algorithms to user-based social
tagging systems. In this paper, we introduce the
concept of overhearing (i.e., at every time step of
the game, a random set of N-delta individuals are
chosen from the population who overhear the
transmitted word from the speaker and accordingly
reshape their inventories). When delta = 0 one
recovers the behavior of the original NG. As one
increases delta, the population of agents reaches a
faster agreement with a significantly low-memory
requirement. The convergence time to reach global
consensus scales as log N as delta approaches
1. Copyright (C) EPLA, 2013
10th International Symposium on Computer Music Multidisciplinary Research (CMMR 2013), Marseille (France), October, 2013. pp.64--77.
23rd International Joint Conference on Artificial Intelligence (IJCAI 2013), Beijin (China), August, 2013.
27th Conference on Artificial Intelligence (AAAI 2013), Bellevue, Washington (USA), August, 2013.
Paris (France), July, 2013.
14th International Society for Music Information Retrieval Conference (ISMIR 2013), Curitiba (Brazil), November, 2013. pp.341--346.
SIGCHI ACM Conference on Human Factors in Computing Systems, ACM, Paris (France), 2013. pp.2205--2208.
2013 Marconi Institute for Creativity Conference (MIC 2013), 80, Bologna (Italy), September, 2013.
14th International Society for Music Information Retrieval Conference (ISMIR 2013), Curitiba (Brazil), November, 2013. pp.275--280.
27th Conference on Artificial Intelligence (AAAI 2013), Bellevue, Washington (USA), June, 2013.
Sony Computer Science Laboratory Paris, January, 2012.
The Evolution of Language (EVOLANG 9), 2012.
The Evolution of Language (EVOLANG 9), edited by:Scott-Phillips, T.C. and Tamariz, M. and Cartmill, E.A. and Hurford, J.R., World Scientific, Singapore, 2012. pp.360--368.
Despite centuries of research, the origins of grammatical case are more mysterious than ever. This paper addresses some unanswered questions through language game experiments in which a multi-agent population self-organizes a morphosyntactic case system. The experiments show how the formal part of grammatical constructions may pressure such emergent systems to become more economical.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, 3, John Benjamins, Amsterdam, 2012. pp.169--205.
Case has fascinated linguists for centuries without however revealing its most important secrets. This paper offers operational explanations for case through language game experiments in which autonomous agents describe real-world events to each other. The experiments demonstrate (a) why a language may develop a case system, (b) how a population can self-organize a case system, and (c) why and how an existing case system may take on new functions in a language.
Proceedings of the 13th Conference of the European Chapter of the Association for Computational Linguistics, ACL, Avignon, 2012. pp.829--839.
German case syncretism is often assumed to be the accidental by-product of historical development. This paper contradicts this claim and argues that the evolution of German case is driven by the need to optimize the cognitive effort and memory required for processing and interpretation. This hypothesis is supported by a novel kind of computational experiments that reconstruct and compare attested variations of the German definite article paradigm. The experiments show how the intricate interaction between those variations and the rest of the German ?linguistic landscape? may direct language change.
Language Grounding in Robots, edited by:Steels, Luc and Hild, M., Springer, New York, 2012. pp.215--234.
Linguistic utterances are full of errors and novel expressions, yet linguistic communication is remarkably robust. This paper presents a double-layered architecture for open-ended language processing, in which ?diagnostics? and ?repairs? operate on a meta-level for detecting and solving problems that may occur during habitual processing on a routine layer. Through concrete operational examples, this paper demonstrates how such an architecture can directly monitor and steer linguistic processing, and how language can be embedded in a larger cognitive system.
Language Grounding in Robots, edited by:Steels, Luc and Hild, Manfred, Springer, New York, 2012. pp.255--276.
Almost all languages in the world have a way to formulate commands. Commands specify actions that the body should undertake (such as “stand up”), possibly involving other objects in the scene (such as “pick up the red block”). Action language involves various competences, in particular (i) the ability to perform an action and recognize which action has been performed by others (the so-called mirror problem), and (ii) the ability to identify which objects are to participate in the action (e.g. “the red block” in “pick up the red block”) and understand what role objects play, for example whether it is the agent or undergoer of the action, or the patient or target (as in “put the red block on top of the green one”). This chapter describes evolutionary language game experiments exploring how these competences originate, can be carried out and acquired, by real robots, using evolutionary language games and a whole systems approach.
Proceedings of the 13th Conference of the European Chapter of the Association for Computational Linguistics, ACL, Avignon, 2012.
Cognitive linguistics has reached a stage of maturity where many researchers are looking for an explicit formal grounding of their work. Unfortunately, most current models of deep language processing incorporate assumptions from generative grammar that are at odds with the cognitive movement in linguistics. This demonstration shows how Fluid Construction Grammar (FCG), a fully operational and bidirectional unification-based grammar formalism, caters for this increasing demand. FCG features many of the tools that were pioneered in computational linguistics in the 70s-90s, but combines them in an innovative way. This demonstration highlights the main differences between FCG and related formalisms.
Language Grounding in Robots, edited by:Steels, Luc and Hild, Manfred, Springer, New York, 2012. pp.1--22.
This chapter introduces a new experimental paradigm for studying issues in the grounding of language and robots, and the integration of all aspects of intelligence into a single system. The paradigm is based on designing and implementing artificial agents so that they are able to play language games about situations they perceive and act upon in the real world. The agents are not pre-programmed with an existing language but with the necessary cognitive functions to self-organize communication systems from scratch, to learn them from human language users if there are sufficiently frequent interactions, and to participate in the on-going cultural evolution of language.
Language Grounding in Robots, edited by:Steels, Luc and Hild, M., Springer, New York, 2012. pp.195--213.
This chapter introduces very briefly the framework and tools for lexical and grammatical processing that have been used in the evolutionary language game experiments reported in this book. This framework is called Fluid Construction Grammar (FCG) because it rests on a constructional approach to language and emphasizes flexible grammar application. Construction grammar organizes the knowledge needed for parsing or producing utterances in terms of bi-directional mappings between meaning and form. In line with other contemporary linguistic formalisms, FCG uses feature structures and unification and includes several innovations which make the formalism more adapted to implement flexible and robust language processing systems on real robots. This chapter is an introduction to the formalism and how it is used in processing.
Language Grounding in Robots, edited by:Steels, Luc and Hild, Manfred, Springer, New York, 2012. pp.153--172.
This chapter introduces the computational infrastructure that is used to bridge the gap between results from sensorimotor processing and language. It consists of a system called Incremental Recruitment Language (IRL) that is able to configure a network of cognitive operations to achieve a particular communicative goal. IRL contains mechanisms for finding such networks, chunking subnetworks for more efficient later reuse, and completing partial networks (as possibly derived from incomplete or only partially understood sentences).
Language Grounding in Robots, edited by:Steels, Luc and Hild, Manfred, Springer, 2012. pp.89--110.
This chapter describes key aspects of a visual perception system as a key component for language game experiments on physical robots. The vision system is responsible for segmenting the continuous flow of incoming visual stimuli into segments and computing a variety of features for each segment. This happens by a combination of bottom-up way processing that work on the incoming signal and top-down processing based on expectations about what was seen before or objects stored in memory. This chapter consists of two parts. The first one is concerned with extracting and maintaining world models about spatial scenes, without any prior knowledge of the possible objects involved. The second part deals with the recognition of gestures and actions which establish the joint attention and pragmatic feedback that is an important aspect of language games.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, John Benjamins, Amsterdam, 2012. pp.233--256.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, John Benjamins, Amsterdam, 2012. pp.1--37.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, John Benjamins, Amsterdam, 2012. pp.41--59.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, 3, John Benjamins, Amsterdam, 2012. pp.207-232.
This chapter explores a semantics-oriented approach to the origins of syntactic structure. It reports on preliminary experiments whereby speakers introduce hierarchical constructions and grammatical markers to express which conceptualization strategy hearers are supposed to invoke. This grammatical information helps hearers to avoid semantic ambiguity or errors in interpretation. A simulation study is performed for spatial grammar using robotic agents that play language games about objects in their shared world. The chapter uses a reconstruction of a fragment of German spatial language to identify the niche of spatial grammar, and then reports on acquisition and formation experiments in which agents seeded with a `pidgin German’ without grammar are made to interact until rudiments of hierarchical structure and grammatical marking emerge.
Five Approaches to Language Evolution, edited by:McCrohon, L. and Fujimura, T. and Fujita, K. and Martin, R. and Okanoya, K. and Suzuki, R. and Yusa, N., Evolang9 Organization Committee, Tokyo, 2012. pp.130--139.
Language Grounding in Robots, edited by:Steels, Luc and Hild, M., Springer, New York, 2012. pp.173--192.
Grounding language in sensorimotor spaces is an important and difficult task. In order, for robots to be able to interpret and produce utterances about the real world, they have to link symbolic information to continuous perceptual spaces. This requires dealing with inherent vagueness, noise and differences in perspective in the perception of the real world. This paper presents two case studies for spatial language and quantification that show how cognitive operations – the building blocks of grounded procedural semantics – can be efficiently grounded in sensorimotor spaces.
Language Grounding in Robots, edited by:Steels, Luc and Hild, M., Springer, New York, 2012. pp.237--254.
Russian requires speakers of the language to conceptualize events using temporal language devices such as Aktionsarten and aspect, which relate to particular profiles and characteristics of events such as whether the event just started, whether it is ongoing or it is a repeated event. This chapter explores how such temporal features of events can be processed and learned by robots through grounded situated interactions. We use a whole systems approach, tightly integrating perception, conceptualization grammatical processing and learning and demonstrate how a system of Aktionsarten can be acquired.
Language Grounding in Robots, edited by:Steels, Luc and Hild, M., Springer, New York, 2012. pp.111-130.
Basic postures such as sit, stand and lie are ubiquitous in human interaction. In order to build robots that aid and support humans in their daily life, we need to understand how posture categories can be learned and recognized. This paper presents an unsupervised learning approach to posture recognition for a biped humanoid robot. The approach is based on Slow Feature Analysis (SFA), a biologically inspired algorithm for extracting slowly changing signals from signals varying on a fast time scale. Two experiments are carried out: First, we consider the problem of recognizing static postures in a multimodal sensory stream which consists of visual and proprioceptive stimuli. Secondly, we show how to extract a low-dimensional representation of the sensory state space which is suitable for posture recognition in a more complex setting. We point out that the beneficial performance of SFA in this task can be related to the fact that SFA computes manifolds which are used in robotics to model invariants in motion and behavior. Based on this insight, we also propose a method for using SFA components for guided exploration of the state space.
Language Grounding in Robots, edited by:Steels, Luc and Hild, M., Springer, New York, 2012. pp.25--44.
This chapter introduces the modular humanoid robot Myon, covering its mechatronical design, embedded low-level software, distributed processing architecture, and the complementary experimental environment. The Myon humanoid is the descendant of various robotic hardware platforms which have been built over the years and therefore combines the latest research results on the one hand, and the expertise of how a robot has to be built for experiments on embodiment and language evolution on the other hand. In contrast to many other platforms, the Myon humanoid can be used as a whole or in parts. Both the underlying architecture and the supportive application software allow for ad hoc changes in the experimental setup.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, 3, John Benjamins, Amsterdam, 2012. pp.111-141.
This chapter studies how basic spatial categories such as left-right, front-back, far-near or north-south can emerge in a population of robotic agents in co-evolution with terms that express these categories. It introduces various language strategies and tests them first in reconstructions of German spatial terms, then in acquisition experiments to demonstrate the adequacy of the strategy for learning these terms, and finally in language formation experiments showing how a spatial vocabulary and the concepts expressed by it can emerge in a population of embodied agents from scratch.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, 3, John Benjamins, Amsterdam, 2012. pp.87--109.
This chapter investigates how a vocabulary for talking about body actions can emerge in a population of grounded autonomous agents instantiated as humanoid robots. The agents play a Posture Game in which the speaker asks the hearer to take on a certain posture. The speaker either signals success if the hearer indeed performs an action to achieve the posture or he shows the posture himself so that the hearer can acquire the name. The challenge of emergent body language raises not only fundamental issues in how a perceptually grounded lexicon can arise in a population of autonomous agents but also more general questions of human cognition, in particular how agents can develop a body model and a mirror system so that they can recognize actions of others as being the same as their own.
Experiments in Cultural Language Evolution, edited by:Steels, Luc, 3, John Benjamins, Amsterdam, 2012. pp.257--276.
This chapter explores a possible language strategy for verbalizing aspect: the encoding of Aktionsarten by means of morphological markers. Russian tense-aspect system is used as a model. We first operationalize this system and reconstruct the learning operators needed for acquiring it. Then we perform a first language formation experiment in which a novel system of Aktionsarten emerges and gets coordinated between the agents, driven by a need for higher expressivity.
ECAI2012: The 20th European Conference on Artificial Intelligence, edited by:De Raedt, L. and Bessiere, C. and Dubois, D. and Doherty, P. and Frasconi, P. and Heintz, F. and Lucas, P., 242, IOS Press, Amsterdam, 2012. pp.798--803.
Language change is increasingly recognized as one of the most crucial sources of evidence for understanding human cognition. Unfortunately, despite sophisticated methods for documenting which changes have taken place, the question of why languages evolve over time remains open for speculation. This paper presents a
novel research method that addresses this issue by combining agent-based experiments with deep language processing, and demonstrates the approach through a case study on German definite articles. More specifically, two populations of autonomous agents are equipped with a model of Old High German (500?1100 AD) and Modern High
German definite articles respectively, and a set of self-assessment criteria for evaluating their own linguistic performances. The experiments show that inefficiencies detected in the grammar by the Old High German agents correspond to grammatical forms that have actually undergone the most important changes in the German language.
The results thus suggest that the question of language change can be reformulated as an optimization problem in which language users try to achieve their communicative goals while allocating their cognitive resources as efficiently as possible.
Advances in Complex Systems, 15, 3--4, 2012.
The question how a shared vocabulary can arise in a multi-agent population despite the fact that each agent autonomously invents and acquires words has been solved. The solution is based on alignment: Agents score all associations between words and meanings in their lexicons and update these preference scores based on communicative success. A positive feedback loop between success and use thus arises which causes the spontaneous self-organization of a shared lexicon. The same approach has been proposed for explaining how a population can arrive at a shared grammar, in which we get the same problem of variation because each agent invents and acquires their own grammatical constructions. However, a problem arises if constructions reuse parts that can also exist on their own. This happens particularly when frequent usage patterns, which are based on compositional rules, are stored as such. The problem is how to maintain systematicity. This paper identifies this problem and proposes a solution in the form of multilevel alignment. Multilevel alignment means that the updating of preference scores is not restricted to the constructions that were used in the utterance but also downward and upward in the subsumption hierarchy.
Computational Issues in Fluid Construction Grammar, edited by:Steels, Luc, Springer, Heidelberg, 2012.
Becoming a proficient speaker of a language requires more than just learning a set of words and grammar rules, it also implies mastering the ways in which speakers of that language typically innovate: stretching the meaning of words, introducing new grammatical constructions, introducing a new category, and so on. This paper demonstrates that such meta-knowledge can be represented and applied by reusing similar representations and processing techniques as needed for routine linguistic processing, which makes it possible that language processing makes use of computational reflection.
edited by:Steels, Luc, 3, John Benjamins, Amsterdam, 2012.
The fascinating question of the origins and evolution of language has been drawing a lot of attention recently, not only from linguists, but also from anthropologists, evolutionary biologists, and brain scientists. This groundbreaking book explores the cultural side of language evolution. It proposes a new overarching framework based on linguistic selection and self-organization and explores it in depth through sophisticated computer simulations and robotic experiments. Each case study investigates how a particular type of language system can emerge in a population of language game playing agents and how it can continue to evolve in order to cope with changes in ecological conditions. Case studies cover on the one hand the emergence of concepts and words for proper names, color terms, names for bodily actions, spatial terms and multi-dimensional words. The second set of experiments focuses on the emergence of grammar, specifically case grammar for expressing argument structure, functional grammar for expressing different uses of spatial relations, internal agreement systems for marking constituent structure, morphological expression of aspect, and quantifiers expressed as articles. The book is ideally suited as study material for an advanced course on language evolution and it will be of interest to anyone who wonders how human languages may have originated.
edited by:Steels, Luc and Hild, Manfred, Springer, New York, 2012.
Written by leading international experts, this volume presents contributions establishing the feasibility of human language-like communication with robots. The book explores the use of language games for structuring situated dialogues in which contextualized language communication and language acquisition can take place. Within the text are integrated experiments demonstrating the extensive research which targets artificial language evolution. Language Grounding in Robots uses the design layers necessary to create a fully operational communicating robot as a framework for the text, focusing on the following areas: Embodiment; Behavior; Perception and Action; Conceptualization; Language Processing; Whole Systems Experiments. This book serves as an excellent reference for researchers interested in further study of artificial language evolution.
New Directions in Logic, Language, and Computation, edited by:Slavkovik, M. and Lassiter, D., Springer, 2012.
Proceedings of the 20th European Conference on Artificial Intelligence (ECAI 2012), edited by:Luc De Raedt et al., 2012. pp.115--120.
Computers and Creativity, edited by:McCormack, J and D'Inverno, M, Springer, 2012.
PLOS ONE, 2012. pp.e37744-1--e37744-8.
The lexicons of human languages organize their units
at two distinct levels. At a first combinatorial
level, meaningless forms (typically referred to as
phonemes) are combined into meaningful units
(typically referred to as morphemes). Thanks to
this, many morphemes can be obtained by relatively
simple combinations of a small number of
phonemes. At a second compositional level of the
lexicon, morphemes are composed into larger lexical
units, the meaning of which is related to the
individual meanings of the composing morphemes. This
duality of patterning is not a necessity for
lexicons and the question remains wide open
regarding how a population of individuals is able to
bootstrap such a structure and the evolutionary
advantages of its emergence. Here we address this
question in the framework of a multi-agents model,
where a population of individuals plays simple
naming games in a conceptual environment modeled as
a graph. We demonstrate that errors in communication
as well as a blending repair strategy, which
crucially exploits a shared conceptual
representation of the environment, are sufficient
conditions for the emergence of duality of
patterning, that can thus be explained in a pure
cultural way. Compositional lexicons turn out to be
faster to lead to successful communication than
purely combinatorial lexicons, suggesting that
meaning played a crucial role in the evolution of
language.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (PNAS), 2012.
One of the fundamental problems in cognitive science
is how humans categorize the visible color
spectrum. The empirical evidence of the existence of
universal or recurrent patterns in color naming
across cultures is paralleled by the observation
that color names begin to be used by individual
cultures in a relatively fixed order. The origin of
this hierarchy is largely unexplained. Here we
resort to multiagent simulations, where a population
of individuals, subject to a simple perceptual
constraint shared by all humans, namely the human
Just Noticeable Difference, categorizes and names
colors through a purely cultural negotiation in the
form of language games. We found that the time
needed for a population to reach consensus on a
color name depends on the region of the visible
color spectrum. If color spectrum regions are ranked
according to this criterion, a hierarchy with [red,
(magenta)-red], [violet], [green/yellow], [blue],
[orange], and [cyan], appearing in this order, is
recovered, featuring an excellent quantitative
agreement with the empirical observations of the
WCS. Our results demonstrate a clear possible route
to the emergence of hierarchical color categories,
confirming that the theoretical modeling in this
area has now attained the required maturity to make
significant contributions to the ongoing debates
concerning language universals.
Geoscientific Model Development, 4, 3, 2011. pp.835--844.
Advances in Artificial Life, ECAL 2011, edited by:Lenaerts, T. and Giacobini, M. and Bersini, H. and Bourgine, P. and Dorigo, M. and Doursat, R., MIT Press, 2011. pp.771--778.
All languages of the world have a way to talk about space and spatial relations of objects. Cross-culturally, immense variation in how people conceptualize space for language has been attested. Different spatial conceptualization strategies such as proximal, projective and absolute have been identified to underlie peoples conception of spatial reality. This paper argues that spatial conceptualization strategies are negotiated in a cultural process of linguistic selection. Conceptualization strategies originate in the cognitive capabilities of agents. The ecological conditions and the structure of the environment influence the conceptualization strategy agents invent and which corresponding system of lexicon and ontology of spatial relations is selected for. The validity of these claims is explored using populations of humanoid robots.
Proceedings of the 23rd Benelux Conference on Artificial Intelligence (BNAIC 2011), edited by:De Causmaecker, P. and Maervoet, J. and Messelis, T. and Verbeeck, K. and Vermeulen, T., KAHO Sint-Lieven, Ghent, 2011. pp.288--295.
This paper compares two prominent approaches in artificial language evolution: Iterated Learning and Social Coordination. More specifically, the paper contrasts experiments in both approaches on how populations of artificial agents can autonomously develop a grammatical case marking system for indicating event structure (i.e. ?who does what to whom?). The comparison demonstrates that only the Social Coordination approach leads to a shared communication system in a multi-agent population. The paper concludes with an analysis and discussion of the results, and argues that Iterated Learning in its current form cannot explain the emergence of more complex natural language-like phenomena.
Physics of Life Reviews, 8, 4, December, 2011. pp.339--356.
The paper surveys recent research on language evolution, focusing in particular on models of cultural evolution and how they are being developed and tested using agent-based computational simulations and robotic experiments. The key challenges for evolutionary theories of language are outlined and some example results are discussed, highlighting models explaining how linguistic conventions get shared, how conceptual frameworks get coordinated through language, and how hierarchical structure could emerge. The main conclusion of the paper is that cultural evolution is a much more powerful process that usually assumed, implying that less innate structures or biases are required and consequently that human language evolution has to rely less on genetic evolution.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, 11, John Benjamins, Amsterdam, 2011. pp.115--146.
This paper presents a design pattern for handling argument structure and offers a concrete operationalization of this pattern in Fluid Construction Grammar. Argument structure concerns the mapping between ?participant structure? (who did what to whom) and instances of ?argument realization? (the linguistic expression of participant structures). This mapping is multilayered and indirect, which poses great challenges for grammar design. In the proposed design pattern, lexico-phrasal constructions introduce their semantic and syntactic potential of linkage. Argument structure constructions, then, select from this potential the values that they require and implement the actual linking.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, 11, John Benjamins, Amsterdam, 2011. pp.205--236.
This paper illustrates the use of ?feature matrices?, a technique for handling ambiguity and feature indeterminacy in feature structure grammars using unification as the single mechanism for processing. Both phenomena involve forms that can be mapped onto multiple, often conflicting values. This paper illustrates their respective challenges through German case agreement, which has become the litmus test for demonstrating how well a grammar formalism deals with multifunctionality. After reviewing two traditional solutions, the paper demonstrates how complex grammatical categories can be represented as feature matrices instead of single-valued features. Feature matrices allow a free flow of constraints on possible feature-values coming from any part of an utterance, and they postpone commitment to any particular value until sufficient constraints have been identified. All examples in this paper are operationalized in Fluid Construction Grammar, but the design principle can be extended to other unification-grammars as well.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, 11, John Benjamins, Amsterdam, 2011. pp.301--330.
Natural languages are fluid. New conventions may arise and there is never absolute consensus in a population. How can human language users nevertheless have such a high rate of communicative success? And how do they deal with the incomplete sentences, false starts, errors and noise that is common in normal discourse? Fluidity, ungrammaticality and error are key problems for formal descriptions of language and for computational implementations of language processing because these seem to be necessarily rigid and mechanical. This chapter discusses how these issues are approached within the framework of Fluid Construction Grammar. Fluidity is not achieved by a single mechanism but through a combination of intelligent grammar design and flexible processing principles.
KI 2011: ADVANCES IN ARTIFICIAL INTELLIGENCE, 7006, Springer, Berlin, 2011. pp.14--25.
One of the key components for achieving flexible, robust, adaptive and open-ended language-based communication between humans and robots – or between robots and robots – is rich deep semantics. AI has a long tradition of work in the representation of knowledge, most of it within the logical tradition. This tradition assumes that an autonomous agent is able to derive formal descriptions of the world which can then be the basis of logical inference and natural language understanding or production. This paper outlines some difficulties with this logical stance and reports alternative research on the development of an ?embodied cognitive semantics? that is grounded in the world through a robot?s sensori-motor system and is evolutionary in the sense that the conceptual frameworks underlying language are assumed to be adapted by agents in the course of dialogs and thus undergo constant change.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, John Benjamins, Amsterdam, 2011. pp.3--30.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, John Benjamins, Amsterdam, 2011. pp.31--68.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, John Benjamins, Amsterdam, 2011. pp.71--145.
Design Patterns in Fluid Construction Grammar, edited by:Steels, Luc, 11, John Benjamins, Amsterdam, 2011. pp.265--298.
This chapter presents an operational grammar for German spatial language, in particular German locative phrases, as a case study for processing distributed information. It investigates the complex interplay of syntactic phenomena and spatial semantics, with a specific emphasis on efficient processing of syntactic indeterminacy and semantic ambiguity. Since FCG applies constructions in a sequence one after the other, the main challenge lies in mutual dependencies between constructions, that is, some constructions require pieces of information in order to make decisions that are only later on provided by other constructions. We present solutions and design patterns for dealing with these processing issues, which all have in common the strategy of postponing decisions as long as possible in processing until all the necessary information for making the decision is available.
Brussels, Belgium, 2011.
This thesis contributes to our understanding of the origins of spatial language by carrying out language game experiments with artificial agents instantiated as humanoid robots. It tests the theory of language evolution by linguistic selection, which states that language emerges through a cultural process based on the recruitment of various cognitive capacities in the service of language. Agents generate possible paradigmatic choices in their language systems and explore different language strategies. Which ones survive and dominate depends on linguistic selection criteria, such as expressive adequacy with respect to the ecological challenges and conditions in the environment, minimization of cognitive effort, and communicative success. To anchor this case study in empirical phenomena, the thesis reconstructs the syntax and semantics of German spatial language, in particular German locative phrases. Syntactic processing is organized using Fluid Construction Grammar (FCG), a computational formalism for representing linguistic knowledge. For the semantics the thesis focusses in particular on proximal, projective and absolute spatial categories as well as perspective, perspective reversal and frame of reference. The semantic investigations use the perspective of Embodied Cognitive Semantics. The spatial semantics is grounded in the sensorimotor experiences of the robot and made compositional by using the Incremental Recruitment Language (IRL) developed for this purpose. The complete reconstructed system allows humanoid robots to communicate successfully and efficiently using the German locative system and provides a performance base line. The reconstruction shows that the computational formalisms, i.e. FCG and IRL, are sufficient for tackling complex natural language phenomena. Moreover, the reconstruction efforts reveal the tight interaction of syntax and semantics in German locative phrases. The second part of the thesis concentrates on the evolution of spatial language. First the focus is on the formation and acquisition of spatial language by proposing strategies in the form of invention, adoption, and alignment operators. The thesis shows the adequacy of these strategies in acquisition experiments in which some agents act as learners and others as tutors. It shows next in language formation experiments that these strategies are sufficient to allow a population to self-organize a spatial language system from scratch. The thesis continues by studying the origins and competition of language strategies. Different conceptual strategies are considered and studied systematically, particularly in relation to the properties of the environment, for example, whether a global landmark is available. Different linguistic strategies are studied as well, for instance, the problem of choosing a particular reference object on the scene can be solved by the invention of markers, which allows many different reference objects, or by converging to a standard single reference object, such as a global landmark. The thesis demonstrates that the theory of language evolution by linguistic selection leads to operational experiments in which artificial agents self-organize semantically rich and syntactically complex language. Moreover, many issues in cognitive science, ranging from perception and conceptualization to language processing, had to be dealt with to instantiate this theory, so that this thesis contributes not only to the study of language evolution but to the investigation of the cognitive bases of spatial language as well.
edited by:Steels, Luc, 11, John Benjamins, Amsterdam, 2011.
Construction Grammar is enthusiastically embraced by a growing group of linguists who find it a natural way to formulate their analyses. But so far there is no widespread formalization of construction grammar with a solid computational implementation. Fluid Construction Grammar attempts to fill this gap. It is a fully operational computational framework capturing many key concepts in construction grammar. The present book is the first extensive publication describing this framework. In addition to general introductions, it gives a number of concrete examples through a series of linguistically challenging case studies, including phrase structure, case grammar, and modality. The book is suited both for linguists who want to know what Fluid Construction Grammar looks like and for computational linguists who may want to use this computational framework for their own experiments or applications.
Journal of the Acoustical Society of America, 2, February, 2011. pp.1089-1099.
Animal Cognition, 2, March, 2011. pp.203-211.
Music Data Mining, edited by:Tao, Tzanetakis & Ogihara, Chapman & Hall / CRC Press, 2011. pp.305-326.
Proceedings of the 22nd International Joint Conference on Artificial Intelligence, IJCAI, Barcelona, Spain, July, 2011. pp.635--642.
Constraints, 2, March, 2011. pp.148-172.
JOURNAL OF STATISTICAL MECHANICS: THEORY AND EXPERIMENT, P04006, Bristol : IOP Publishing, 2011.
We Can Change the Weather: 101 Cases of Changeability, edited by:Wynants, M. and Engelen, S., VUBPress Brussels University Press, 2010. pp.46-47.
Proceedings of the 8th International Conference on the Evolution of Language (Evolang8), edited by:Smith, A.D.M. and Schouwstra, M. and de Boer, B. and Smith, K., World Scientific, Singapore, 2010. pp.145-152.
Proceedings of the Ismir 2010 Conference, Utrecht, 2010. pp.321-326.
The Evolution of Language (EVOLANG 8), edited by:Smith, A.D.M. and Schouwstra, M. and de Boer, B. and Smith, K., World Scientific, Singapore, 2010. pp.336--343.
Pronouns form a particularly interesting part-of-speech for evolutionary linguistics because
their development is often lagging behind with respect to other changes in their language. Many
hypotheses on pronoun evolution exist ? both for explaining their initial resilience to change as
well as for why they eventually cave in to evolutionary pressures ? but so far, no one has proposed
a formal model yet that operationalizes these explanations in a unified theory. This paper
therefore presents a computational model of pronoun evolution in a multi-agent population;
and argues that pronoun evolution can best be understood as an interplay between the level
of language strategies, which are the procedures for learning, expanding and aligning particular
features of language, and the level of the specific language systems that instantiate these
strategies in terms of concrete words, morphemes and grammatical structures. This claim is
supported by a case study on Spanish pronouns, which are currently undergoing an evolution
from a case- to a referential-based system, the latter of which there exist multiple variations
(which are called le�smo, la�smo and lo�smo depending on the type of change).
We Can Change the Weather, 100 Cases of Changeability, edited by:Wynants, M. and Engelen, S., Crosstalks, 2010.