Towards Artificial Societies
Plancton art studio, Rome, Italy
The progress in the scientific understanding/simulation of the natural evolution mechanisms and the first technological realizations, intelligent toys, self reproducing machines, smart information retrieval agents on the web, are creating the base of a “new step in evolution”: the coming of the artificial beings and artificial societies. Although this could seem a visionary hypothesis drawn by technological advances, in our opinion it raises interesting questions: are those true life forms, is this true life evolution? As a matter of fact, a new cultural paradigm inherited from the theories of evolution and complexity is already growing: culture itself, aesthetics and intelligence are seen as emergent self-organizing qualities of a collectivity, evolved along time through both genetic and language evolution. For these reasons artificial life is going to be an anticipatory and incredibly creative area for the artistic expression and imagination. In this paper we try to correlate some elements of research in the fields of artificial life, art and technology, in order to sketch the development of hybrid digital worlds, where the artificial beings are able to evolve their own culture, language and aesthetics, and are able to interact with natural beings. Finally we report our experience on an interactive audio-visual art installation, based on two connected hybrid virtual worlds based on artificial life environments. In these worlds, the digital beings can interact, reproduce and evolve through the mechanisms of genetic mutations. People can interact with the artificial beings, creating an hybrid ecosystem and generating emergent shapes, colors, sound architectures and metaphors of imaginary societies.
Recent trends in information and communication
technologies, reveal an impressive convergence among different research disciplines, AI (artificial
intelligence), VR (virtual reality) and AL (artificial life). More and more
projects involving environments where real people can interact with artificial
entities are realized. The concept of “virtual reality” is now merging in the wider concept of “virtual
world”, as conjunction of a virtual environment with artificial evolving
creatures. In these projects, the efforts on the development of “intelligent
beings” acting as “autonomous agents”
in a “virtual environment”, raise
basic questions related to the current definition of terms as life,
intelligence, evolution. This convergence is stimulating a completely new
approach in the definition of current
virtual worlds architectures. In the more advanced applications it can even
produce a paradigm shift. The man-machine
interface is shifting into hybrid
ecosystem. The environment is no
more a static virtual set of rules,
and becomes a dynamic environment,
co-evolving under the action of the living agents. Interaction and dynamics in
such worlds cannot be based on an action-reaction list of correspondences, but should be based on an open
evolution, where genetics and self-organization allows the survival of the
overall system. Recently an impressive collection of progresses have been made
in the field of reproduction of the autonomous behavior, particularly in the
field of the artificial life. The historical dream of Von Neuman [VON66] of
self-reproducing machines seems today more at hand: new advances showed
simulated machines able to develop an increase in complexity at each
self-reproduction stage (see the "Langton loop" [LAN84]). The first
attempts on self-reproducing machines succeded recently [LIP00]. From the technology point of view, the well
known tamagochi, a very low technology game, had an enormous success just for a
smart emulation of some simple life functions. The Aibo toy-robot of Sony
[KUS00] is probably the first (commercial) one of a long series of toys which
learn playing and develop an autonomous behavior. Current experimentation on robots developing a communication
language [KAP00], will probably give some more answers on the possibility that
artificial beings could develop “culture".
An interesting more dimension has been shown by the use of the evolution of artificial societies in order to develop
the control strategy for complex industrial processes [ANB00]. The already
mentioned basic questions raised by all these ideas, stimuli and advances, are
answered today, in the world of artificial life thinkers, in two
ways: the weak alifers (all is just a
simulation of real life) and the hard
alifers ( these are realizations of a new and real life form). One the main
support to these interpretation comes from the concept of autopoiesis of Maturana and Varela [MAT92] as a network of
production processes where the function of each component is to participate to
the production, or transformation, of other components on the network. In few
words, living systems are characterized by the production/transformation of
"itself". In alife based
systems, often it is really difficult to asses this property, and most of the
time the concept of evolvability
[LAN89] is used as a qualitative measure of a sort of
potential of life.
Fig 1: Volute. Generated from the alife interactive installation "Relazioni Emergenti".
This convergence of scientific and technological
contexts, has been anticipated by the complexity
theories, which gave the basic theoretical support for the re-unification
of physical and social sciences. This is going to be a key interference area
between science/technology and art. In the last few years, several artists
started exploring the potential of artificial life concepts in artistic fields.
The development of new languages and tools is transferring the visions of these
artists (artlifers) into tangible
objects (artworks, entertainment systems, games, technologies). One of the expressive dimensions is the idea
of evolution: a progressively
increase of aesthetics [SIM94], or a development of intelligence or
emotionality [TOS96], or an adaptation to the environment [TER98]. Another
theme is the development of complexity and the biodiversity [SOM97, ANN98]. In
most of the cases, the suggestion is focalized on the evolution of one [TOS96]
or few artificial individuals [RIN00], or on a restricted number of species
[SOM98]. Other approaches are based on the dynamics of large population (artificial societies [ANN99]). Also the evolution time is an important aspect in
the alife art expression, i.e. the correspondence between the evolution window presented in the
artwork with the “true” overall
evolution time. A well developed individual [TER98] is often taken as an
indicator of the evolution direction, and different artworks enhance the
evolution dynamics perception, allowing to detect it in short times [ANN98].
One of the most interesting aspects is the relation between the artist, the
observer and the artwork. The artwork is a generative context based on open
simulators, and the interesting aspects appear as emergent qualities [KAW99, SOD00, HEB99, BRO99]. This has been
referred as art of emergence in [AP99].
The relation between the creator and the artwork is going to be very dynamic, and the artwork seems to have
his own personality. The creative process is a dialectical interference between
the artist and the artwork in order to drive, improve, select or simply open the final result. Another element
which can constitute a real challenge in the expressive play, is to open this
relation to the people interaction. The interaction with single/few people
[SOM98] or with the web community [RAY98,ANT99] can open the evolution to
higher complexity. The interaction can transform the artist-artwork system in
an emergent relationship among the
artist, the actors and the artificial
individuals. That means an
hybrid living ecosystem where real people and artificial beings can start up new imaginary worlds.
Fig 2: Real-artificial interaction (from the alife interactive installation "Relazioni Emergenti").
By our point of view one of most important issues identified in these technological, scientific and artistic research is that intelligence of living beings is the a result of the collective accumulation of positive genetic and behavioral mutations and self-organization strategies, developed during a long evolution time. This concept, enounced by J. Monod [MON71], can be the base for an evolving artificial society. With a single powerful computer we can realize good alife simulations [EPS96, CAS97], but the boundary of this world is really too narrow to achieve a good degree of evolvability. The translation of these experiences on a network of computers can raise the possibility of development of an autonomous digital life. Some experiences in this sense are encouraging, as in the project Tierra [T. Ray, RAY98], where programs are able to reproduce itself and travel on a network searching for available computing power (cpu) and life space. Other interesting experiences are the development of intelligent avatars, digital creatures with little autonomy representing a real person, on the network. The practical application of these creatures in virtual shops, entertainment, publicity, is growing up very fast, and party for avatars are already organized by the Biota group [BIO00]. The thesis is that we are at the birth of the first world wide artificial society. Maybe we have to wait several decades to achieve enough computational power, enough network space, enough degree of evolvability, but presently we are founding the bases of a new life dimension. Whether this is a new dimension for real beings, or the birth of a completely new specie (the digital one), is a matter of opinion. In the Monod anticipation [MON71], (see also the punctuated equilibrium theory of Kauffman [CAP96] ) evolution proceeds through large steps. The most important steps are connected with the availability of new lands, new technology, new environmental conditions. One of the biggest known steps is often associated with moving of living beings from sea to earth. The development of language technology was another important step, allowing the bases of cultural development (the possibility of a collective memory). In this sense we identify the computers and the internet network both as new technology and new land available for a further step in evolution.
The vision exposed in the previous paragraph is
clearly a subjective imaginary projection of observed results in the cultural
domain of today. We imagine our work of artists as explorers and founders of a digital plancton which, combined with
efforts of many other people, will contribute to this evolution. We started
with an experiment, producing black-white images exposed the first time in '94
[Viterbo, Italy, ONOFF Gallery] and published in the first paper in '98 [ANN98]
with autonomously growing filaments. This experiment was impressive for the
possibility to show social dynamics like the development of cultural
biodiversity, islanding, pioneers, unconscious cooperation, development of
social classes stratification. Furthermore that images showed an incredible
emulation of natural shapes. From this experience we understood that these kind
of environments contain a massive potential for expression of the
social/communication dynamics. In few words the artificial societies work
as generators of virtual metaphors for the real world.
Fig 3: Solo. Generated from the alife interactive installation "Relazioni Emergenti".
This concept could be considered one of the key themes of Plancton artworks: exploring the artificial being and artificial societies as a digital mirror in which the human beings culture is reflected. Creativity, imagination, aesthetics, language can be extended/explored in artificial beings, built on the personal vision of the artist, and modified during the digital life evolution. In order to carry out this exploration there are is a fundamental problem to solve: how we can communicate with artificial beings ? Or better how humans and artificials can develop a creative inter-contamination? This is one of the central items of Plancton research, i.e. interaction in an hybrid ecosystem. Our effort is concentrated to experiment audiovisual interactive installations which explore the suggestions and visions aforementioned. In the following we report an example of an artwork (Relazioni Emergenti) which represent today the state of the art of the Plancton research.
Relazioni Emergenti (Emergent Relationships) is an life environment of artificial individuals endowed with own autonomy and character. They can interact, reproduce and evolve through the mechanisms of genetic mutations. The installation consists in one retro-projected screen which represents the artificial life environment. In front of the screen the observers can interact with the environment itself. A video-camera detects the positions of the observers which become zones of life germination. The observer can sees filaments growing from his location and interacting with that ones generated by other observers. Every filament is a bearer of a sound message sent to a sound synthesizer. The global result is a whole of parallel sonorities creating coherent sound architectures. The population evolves developing emerging behaviors rendered as continuously new shapes and graphical/acoustical patterns.
Fig 4: The real people give the life to the artificial ones. (from "Relazioni Emergenti").
5.1 The Alife Environment
The alife context is a two-dimensional space
initially empty. At the beginning, few individuals are let in the space and
they begin to reproduce and develop a population. An individual is a filament
which at the beginning is composed by a single cell. At each evolution cycle,
the filament grows according to several models of movement and to a rate of
growing. All the parameters for the dynamics, reproduction and death are
recorded in a genetic map which is defined at the individual birth and remain
constant during the individual life. The movement is the composition of a
deterministic component and a random component. The reciprocal importance of
the two components is regulated by a parameter named irrationality. High values for this parameter cause a totally
random movement; low values cause a totally deterministic movement. Different
models defined characters have been
developed for the deterministic component.
The character unforeseeable is
related to a movement with an homogeneous probability in direction changes. For
the character constant, a higher
probability is associated to a pre-fixed curvature in direction changes. The evolutive character is related to a
movement with a curvature evolving along the time. The character establishes an emotive relation between the genetic
characteristics and the graphic patterns. The straight lines lets imagine a
rational-analytic thought or an unexpressed creativity. Lines with a constant
bending evoke a constant foreseeable behavior, while the chaotic variability of
the paths is referred to the irrationality. A line changing progressively its
features induces the idea of a slow evolution. Finally a global environment
parameter, freedom, constitutes a
constraint for the movement. A high environment freedom allows the individuals
to follow their choices for the movement; a low value pushes the individuals to
reduce the curvature of their movement. The velocity of the movement is
affected by an environment parameter: the energy.
High energy means the maximum probability to move at every cycle. In this
context, energy is a feature of the environment and its value is different cell
by cell changing during the evolution. In this sense, the energy is related to
the survival probability. As explained in the following, this parameter is used
for the interaction between the artificial individuals and the real people. The
death of the individual can occur for accidental or natural reasons or for
total reduction of the length. Furthermore, if the trail of an individual
clashes against another individual, generally he dies. A very little
probability of survival is allowed depending by the clash angle. The
reproduction model is asexual. The offspring has a genetic map similar to that
one of the father, except some mutations in the genetic parameters depending by
the mutation rate. Through this mechanism, the population evolves and different
phenotypes can be developed in the same evolution. The reproduction is
regulated by a reproduction probability and it can occur only if the number of
living individual is less than a maximum number. This position causes a very
strange behavior in the development of the society in the sense of not-
homogeneous colonization of the space and development of a spatio-temporal complexity.
Fig 5: The real people give the life to the artificial ones. (from "Relazioni Emergenti").
5.2 Color and Sound Synergy
The images represented on the screen are the rendering of the 2D life space where the individuals move and live. In addition to the filament position, also the color is redefined every cycle. Every graphical variable (hue, saturation, value, width of the line) is connected with some specific features of the individual like: specie, character, irrationality, curvature, direction, position, age and level in the genealogical tree. The different combinations of the models allows an impressive variety of colors, tonalities and patterns. The global graphical result depend very much by the filament dynamics and society evolution. Some phenotypes are able to develop a very intense vibration of features in little space producing an impressionist style of color deposition. In other cases very smooth color shading are produced by phenotypes slowly evolving in large spirals. Every individual is bearer of a sound which changes at each evolution step. The best individuals of any species are selected on the base of a fitness indicator depending on the energy they catch from the interacting people. These individuals access to the sound channels playing their notes. Like the color modeling, the sound characteristics of each individual are coded on the base of the individual genetic and environmental features. For each specie a different instrumental timbre is assigned. In addition, a dynamic relation is established on the base of different models corresponding to some standard musical modes and chords (Chromatic, Major, Minor Melodic, Minor Harmonic, Pentatonic Major, Pentatonic Minor, Blues, Major, 7th, 7th dominant, Diminished, etc...). Changing the musical mode, the global emotive impact is very different. This information is recorded in the genetic map. Other important sound features as amplitude, roughness, pitch etc. are directly tied to the local dynamics of the evolution, i.e. to the path followed by the individual as a result of the environmental constraints. The global result is the development of many parallel melodies with similar characteristics but different scales, timbres and sometimes modes or tonalities. It is important to note that the different phenotypes developed during the evolution (i.e. the reproduction rate or the movement randomness) are clearly apparent in the acoustical dimension where the human ear has an incredible power of dynamics perception. The translation of the alife phenotypes into both image and sound dimensions produces a strong synergy of the two media, thus enhancing the perception of the system evolution.
A video-camera is located at the bottom (central
line) of the screen with the central view axe tilted in order to look the
interaction area from the bottom. The signal of the camera is sent to the
computer and a continuous difference with the previous image is computed in
order to detect only the observer instantaneous movements. From this image the
distance of the observer from the screen for every vertical line is computed. A
second camera located on the left side of the screen (central line) can detect
the distance for every horizontal line. The composition of the information
coming from the two images gives the two dimensional map of observer activity
in front of the screen. The observer activity is normalized and transformed in
the energy map which determines the life activity in terms of higher filament
dynamics and higher reproduction rate. In this way the real people can interact
with the artificial society influencing the path of evolution and pushing some
specific specie of individuals (fig. 5, 6). In the metaphor, the real people
gives life chances to some of the artificial ones. The interacting observer
cannot operate a deterministic control but only stimulate the artificial
society, whose answer depends by the character of the individuals mostly
solicited. Also the observer can push some specific colors or sounds,
experiencing the emergence of some specific graphical
and acoustical phenotypes.
Fig 6: Cooperative creation between people and artificial individuals.
5.4 Emergent Behavior
The first observation is that the collective development constitutes a new entity with its own autonomous and coherent pattern and with characteristics descending from the interaction and features of the population of individuals. Changing the parameters of the process, the set up generates very different patterns, remembering the growth of populations (plants, animals, neural networks), landscapes (rivers, fractures, mountains, cultivated fields), human artifacts (chips, glass fragments, architectures) visions (anthropomorphous shapes, animals) or simply emotional attitudes. All these shapes are characterized by a completely different distribution in the space and by different fractal dimensions. The evolution process generates strong changes in the modality of the colonization of the life space. This mechanism is due to the dynamic action of dominant individuals which act like pioneers pushing the life in the void space. During this colonization they create strong divisions in the space and the subsequent colonization develop local communities of individuals (micro-societies). The action of the pioneers creates a mechanism of islanding which appears in the images as the coexistence of close different graphical and acoustical phenotypes with a limited contamination. The global result is the development of biodiversity in terms of colors, patterns and sound. Another interesting aspect is the change in the individual phenotypes during the evolution, due to an emergent selection. At the beginning, smooth curvatures are self-selected due to the higher average life they are able to reach. During the evolution the micro-societies characterized by straight lines are filtered because of they are not able to bypass obstacles (high coherence, low flexibility). Too much chaotic micro-societies (high level of irrationality in the curvature changes) are filtered because of the individuals clash each other (internal fight and chaos). In the final part of the evolution, the available space is reduced, and the most suitable phenotypes are micro-societies with short paths, high reproduction rate and medium irrationality. This kind of societies are able to diffuse in every available space. This mechanism produce interesting evolving sound and graphical patterns.
5.5 Experiencing the interactive installation
It is interesting to note that the interaction of the participating people, widens the possibility of evolution. Generally the people, with their movements, try to push a specific phenotype at a time using the hands as a sort of life brush. During the interaction, they alternate the balance of the development between several phenotypes, influencing the evolution and composing vibrating patterns and sound architectures. The apparent fact is the appreciation for a hidden fundamental aspect of life: the biodiversity, or in more general terms the aesthetics of biodiversity. The audio-visual emerging contexts are open both in the sense of esthetical shapes, and in terms of relations between the people and the artificial individuals: this could be a mirror of the real world. We imagine the cultural systems and the communication webs as systems where nothing is pre-determined, but the system evolves through local mechanisms of interaction and fundamental events. With a jump in lower scale, intelligence, consciousness and psyche can be revised as self-organizing phenomena inside of a complex system like a natural being. Starting from the idea that the individual context is the emerging own configuration of psychic fragments, the interaction between two or more individuals is revised as the interaction of two or more micro-societies.
Relazioni Emergenti was built in several versions. One of the most
interesting regards the first step of the implementation of the idea of communicating worlds [APV00]. We realized two separated and autonomous
interactive installations based on two computers, two projection screens, and
two interaction areas. Then we established a data link between the two
computers. Trough this communication channel some individuals can travel and
migrate from a world to the other. The travelling individual diffuse his
genetics and features to the other world through the offspring. In this way a
contamination between two different evolutive paths is established (fig. 7),
not only in terms of graphical patterns and sound, but also in
Fig 7: Contamination in two connected artificial worlds
An important problem we had to face at this stage was the relation between the individual and the environment. In a general way an individual, developed in a world with a specific set of environmental constraints (rules), could appear (manifest itself) different in another world with a different set of rules. In some way the aesthetic and behavioral identity of an individual is related to the specific environment where he lives, and changes in other environments. This is a interesting open problem. Another effect which was quite evident in the connected worlds installation was the following: the evolution dynamics at the beginning of the diffusion in the void space are very different with respect to second phase of evolution, when the space is very dense of individuals. After a migration, a sort of transition to the beginning is induced and the new specie changes rapidly its social characteristics. The concepts exposed in this first pilot artwork are easily extensible to a network of computers. In this not deterministic network, the migrating individuals can transport any kind of information like sound strings or signals, images, movies, texts, colors, voices, etc.. The interesting aspect is that the people interacting on the network nodes, communicate not only with their own world but with all the network. The media we have described is still a closed environment in sense of a fixed number of nodes in the network. This limit can be removed using a different approach, under investigation at Plancton Art Studio. The idea is to establish a sort of a life network server and open new temporary remote worlds to people connecting with the server. The life flows partially to/from the new world, and stops when the connection is concluded. The final step in this imaginary path could be the removal of the server, by allowing each local world to act like a server on its own, to self-sustain the life process with the temporary connection events of people interacting on the network. This last step seems really difficult and a strong effort is required not only in terms of technology but also in terms of the ability of the individuals to adapt to very fast changes of the environment. This last aspect introduces one of the more fashionable and complex aspects of the artificial societies: the evolvability. The concept of evolvability is connected to the potential of evolution of an artificial society. Most of the simulations in the scientific field are built in order to explain natural mechanisms of evolution, or animal behaviour, or to solve practical problems (robots, toys, chemical, control etc..). In these cases we have no need to build an extremely fast evolving system. At the contrary, when we want to use alife for creativity and aesthetics, the needed degree of evolvability corresponds to the dimension and richness of our language. The first degree of freedom is the possibility to evolve the information transported by the individual itself (color, sound, images, shape, text, etc..). The aesthetics manifestation of the single individual is exactly the appearance of the information contained in temporary status or in the genetics of the individual itself. The next degree is the possibility to evolve the behavioral parameters written in the genetic map (dynamics, interaction, reproduction, life & death, etc...). This is important in order to generate different relation and different modalities of aesthetical self-organization. A third level of evolvability is driven by the people interaction. With their instinct and personal harmony, the interacting people can drive the society in absolutely not foreseeable situations. This is the level reached at this moment with the installation Relazioni Emergenti. The technological complexity of this implementation is not high. Much more difficult is to give an aesthetical sense to the evolution-interaction environment. These level of evolvability could be sufficient to develop cooperation, sexuality, coevolution, biodiversity, high level of complexity and rich metaphors of social dynamics. One of the most interesting aspects to explore is the communication dynamics. With these instruments it is possible evocate some mechanisms like emulation, selection, pushers or transporters of messages exploring the culture genetics. Finally, a fourth level of evolvability, which is much more difficult to implement and control, is to give to individuals the possibility to evolve the behavioral and phenotypical models and the genetic structure. This possibility enlarge incredibly the possible complexity of the future generated creatures. This could be a good base to open really the evolution and give to the individuals the possibility of develop some features like language, culture, affection, imagination and, last, intelligence. Some middle way solutions are more easy to implement (lists of models, genetic programming, etc..) but paying a lot in terms of evolvability.
[ANN98] Annunziato, M. 1998. The Nagual Experiment, in Proc. of 1st Int. Conf. Generative Art, Milan (IT).
[ANN99] Annunziato, M. 1999. Emerging Structures in Artificial Societies, in Creative Application Lab CDROM, Siggraph, Los Angeles (CA). For Artificial Societies see also http://www.plancton.com/
[AP99] Annunziato M and P. Pierucci, 1999. The Art of Emergence, in Proc. of 2nd Int. Conf. Generative Art, Milan (IT).
[APV00] M. Annunziato, P. Pierucci. Interactive Audio-Visual Installation exposed in the contest of "Virtuality" Annual Int. Conf., Turin, 2000.
[AP00] M. Annunziato, P. Pierucci, Emergent Relationships, In: Int. Conf. Alife VII, Portland (OR), 2000, Workshop "Artificial life in Art, Design and Entertainment".
[ANB00] Annunziato M. , Bertini I. , Pannicelli A., Pizzuti S. , Tsimring L. :In: Proc. of Int. Conf. CCSI2000 Complexity and Complex System in Industry, Warwick(UK), September 2000.
[ANT99] Antonini, R. 1999. Let Improvise Togheter, in Proc. of 2nd Int. Conf. Generative Art, Milan (IT).
[BIO00] The Biota group. http://www.biota.org/.
[BRO99] B. Brody, C. Hartman. BLUI, a Body Language User Interface for 3d gestural drawing. http://art-web.cla.uaf.edu/blui/pages/spiePaper.html.
[CAP96] F. Capra. The Web of Life, Doubleday-Anchor book, New York, 1996
[CAS97] J. Casti. Would-be Worlds. John Wiley & Son, 1997
[EPS96] J. Epstein, R. Axtell, Growing Artificial Societies, Brooking Institution Press, The MIT Press, 1996.
[HEB99] J.P. Hebert, Ulysses: Sand as a Medium, The Mathematica Journal, Vol . 7, Iusse 3, 1999.
[LIP00] H. Lipson, J. Pollack, Evolving Creatures. In: Int. Conf. Alife VII, Portland (OR), 2000.
[LAN84] C. Langton, Self-Reproduction in Cellular Automata. Physica D, 10:135-144,1984.
[LAN89] C. Langton. Artificial Life. C. Langton Ed. Addison-Wesley. pp. 1-47, 1989.
[KAP00] F. Kaplan, Semiotic schemata: selection units for linguistic cultural evolution. In , In: Int. Conf. Alife VII, Portland (OR).
[KAU93] S.A. Kauffman. The Origins of Order: Self-Organization and Selection in Evolution. Oxford University Press, 1993.
[KAW99] Kawaguchi, Y. 1999. Cellular Growth, in Electronic Art and Animation Catalog, Siggraph, Los Angeles (CA).
[KUS00] M. Kusahara, The Art of Creating Subjective Reality: An Analysis on Japanese Digital Pets, In: Int. Conf. Alife VII, Portland (OR), 2000, Workshop "Artificial life in Art, Design and Entertainment".
[MAT92] H. Maturana, F. Varela. Autopoiesis: The Organization of the Living. 1973.
[MON71] Monod, J. Chance and Necessity. New York: Knopf, 1971.
[RAY98] Ray, T. S. 1998. Evolution as Artist, in Art @ Science, C. Sommerer and L. Mignonneau Eds., Springer-Verlag.
[RIN00] K. Rinaldo, Autopoiesis, In: Int. Conf. Alife VII, Portland (OR), 2000, Workshop "Artificial life in Art, Design and Entertainment".
[SIM94] Sims K., 1994, Evolving Virtual Creatures, in Computer Graphics, Siggraph Conf. Proc.
[SOD00] C. Soddu, New naturality: a Generative Approach to Art and Design. In: Int. Conf. Alife VII, Portland (OR), 2000, Workshop "Artificial life in Art, Design and Entertainment".
[SOM97] Sommerer, C. and L. Mignonneau, L. 1997. A-Volve - an evolutionary artificial life environment. In: Artificial Life V . C. Langton and C. Shimohara Eds., MIT, pp. 167-175.
[SOM98] Sommerer, C. and L. Mignonneau, 1998. Art as a Living System, , in Art @ Science, C. Sommerer and L. Mignonneau Eds., Springer-Verlag.
[TOS96] Tosa, N. 1996. The aesthetics of artificial life, in A-life V Workshop, pp. 122-129.
[TER98] Terzopoulos, D., 1998. Artificial Life for Computer Animation, in Art @ Science, C. Sommerer and L. Mignonneau, Eds., Springer-Verlag.
[VON66] Von Neuman J. The Theory of Self-Reproducing Automata. Arthur Burks Ed. Univ. of Illinois Press, 1966.