RAP art work
Robot Art: A New Kind of Art
Mankind has been intrigued by the possibility of building artificial creatures. For the ancient Greeks this possibility was provided by techné, the procedure that Aristotle conceived to create what nature finds impossible to achieve. Hence, under this view, techné sets itself up between nature and humanity as a creative mediation.
This was the path taken by Norbert Wiener as he opened up the cybernetic perspective, viewed as the unified study of organisms and machines . One line of development linked to this approach gave rise to the familiar humanoid robot, inspired by the von Neumannian self-replicating automata and based on the top-down attitude of the earliest Artificial Intelligence . A much more interesting trend, also stemming from the seminal work of Wiener but intended to "take the human factor out of the loop", emerged in the mid-1940’s with William Grey Walter, who proposed turtle-like robots that exhibit complex social behavior. This was the starting point for a new behavior-based robotics, abolishing the need for cognition as mediation between perception and plans for action.
This line of research was pursued in the 1980’s by Rodney Brooks , who began building six legged insect-like robots at MIT. This new generation of robots was based on Brooks’ "Subsumption Architecture", which describes the agent as composed of functionality distinct control levels under a layered approach. The addition of new layers doesn’t imply changes in the already existing layers. The aforementioned control levels then act in the environment without supervision by a centralized control or action planning centre. Also, no shared representation or any low bandwidth communication system is needed.
The most important concept in Brooks´ reactive robots is "situatedness", which means that the robot’s behavior refers directly to the parameters sensed in the world, rather than using inner representations. Linked to this concept is the "embodiment" feature, which corresponds to the fact that each "robot as a physical body and experiences the world directly through the influence of the world in that body".
The idea of collective robotics appeared in the 1990’s from the convergence of the above described Brooks´ architecture with a variety of bio-inspired algorithms, focused on new programming tools for solving distributed problems. These bio-inspired algorithms stemmed from the work of Christopher Langton, who launched a new avenue of research in AI denoted Artificial Life that "allows us to break our accidental limitations to carbon-based life to explore non-biological forms of life" .
The well known collective behavior of ants, bees and other eusocial insects provided the paradigm for the swarm intelligence approach of aLife. This bottom-up course is based on the assumption that systems composed of a group of simple agents can give rise to complex behavior, which depends only on the interaction between those agents and the environment. Such an interaction may occur when the environment itself is the communication medium and some form of decentralized self-organized pattern emerges without being planned by any exterior agency.
Based on ants and other social insect’s studies , I have tried to reproduce artificially a similar emergent behavior in a robot swarm. These insects communicate among themselves through chemical messages, the pheromones, with which they produce certain patterns of collective behavior, like follow a trail, clean up, repair and build nests, defense and attack or territory conquest. Despite pheromone not being the exclusive way of communication among these insects - the touch of antennas in ants or the dance in bees are equally important -, pheromonal language produces complex cognition via bottom-up procedures. Pheromone expression is dynamic, making use of increments and decrements, positive and negative feedbacks. Messages are amplified when pheromone is reinforced, and lose "meaning" when breeze disperses it. It is also an indirect form of communication, coined stigmergy by Grassé , from the Greek stigma/sign and ergon/action. Between the individual who places the message and the one who is stimulated by it, there is no proximity or direct relation.
Following these principles, I have replaced pheromone by color in my first ant-robots (2001). The marks left by one robot triggers a pictorial action on other robots. Through this apparent random mechanism abstract paintings are generated, which reveal well defined shapes and patterns. These robots create abstract paintings that seem at first sight just random doodles, but after some reflexive observation color clusters and patterns become patent. Through the recognition of the color marks left by a robot, the others react to it reinforcing certain color spots. The process is thus everything but arbitrary. As far as I know, ArtSBot (Art Swarm Robots)  was the first art project to use emergent organization for developing robot creativity. Every previous experiment focused exclusively on randomness or sometimes on target strategies leading the machines to fulfill a pre-determined program created by the human artist. On the contrary, ArtSBot was ment to put into practice the utmost possible machine autonomy, aimed at producing original paintings. In operational terms, ArtSBot consists of a series of small "turtle" type robots, equipped with two felt pens and a pair of RGB sensors pointing to the painting plan. With these "eyes" the robots seek color (chromotaxis), determine if it is hot or cold, choose the corresponding pen and strengthen it by a constant or variable trace. To begin the process, when the canvas is still blank, the robots leave here and there a small spot of color randomly. Based on these simple rules, unique paintings are produced: from a random background stands out a well defined composition with intense shapes of color. In other words, initial randomness generates "order". The process is emergent and based on the properties of stigmergy.
The artistic product of these robots is entirely original. In the same way that somebody who writes a book cannot be considered as a mere instrument of his primary school teacher, robots cannot be seen as simple instruments of the artist that conceived and programmed them. There is an effective incorporation of new and non predetermined information in the process. And that cannot be called anything but creativity. It is true that consciousness is lacking to this creativity. But if we look at the history of modern art, it is obvious that, for example, surrealism tried to produce art works exactly in these same terms. The "pure psychic automatism", the quintessential definition of the movement itself, appeared as a spontaneous, non-conscious and without any aesthetic or moral intention technique. In the first Surrealist Manifesto André Breton (1924) defined the concept in this way: "Pure psychic automatism by which it is intended to express, either verbally or in writing, the true function of thought. Thought dictated in the absence of all control exerted by reason, and outside all aesthetic or moral preoccupations." . In the field of the visual arts, Pollock it is who better fulfills this intention by splashing ink onto the canvas with the purpose of representing nothing but the action itself. This was coined Action Painting, as it is well-known. Perhaps, because of that, the first paintings from my robots are, aesthetically, so similar to the ones of Pollock or André Masson, another important automatism based painter. In his surrealist period, this artist tried frequently to prompt a low conscious state by going hungry, not sleeping or taking drugs, so that he could release himself from any rational control and therefore letting emerge what at the time, in the path of Freud, was called the subconscious. The absence of conscience, external control or pre-determination, allow these painting robots to engender creativity in its pure state, without any representational, aesthetic or moral intention.
RAP (Robotic Action Painter), created in 2006 for the Museum of Natural History in New York, is an individualist artist and not a swarm, but makes use of the same composition methods based on stigmergy and emergence. This robot is additionally able to determine, by its own means, the moment in which the painting is finished. Previous versions didn't have this capacity being conditioned by battery discharge or my will to stop the process. RAP's decision is taken based on the information that it gathers directly from the painting, what produces a considerable variation of time and form, since RAP can decide that the work is complete after a relatively short while (entailing accordingly a low pictorial expression) or can extend the picture construction for a quite long period, making it much more dense and complex. The "secret" of this behavior is in the significant change of the sensors, which passed from two to nine "eyes", allowing now the reading of local patterns, in addition to color spots. RAP is also my first robot to sign its works.
ISU, the poet robot also created in 2006, has the ability to write letters and words producing poems and emergent compositions based on the letter, quite similarly to the Lettrism style, artistic movement that followed Surrealism.
These references to 20th century art movements do not seek any kind of historical legitimacy, but are intended simply to show how certain morphogenesis processes produce similar results in human as well as non-human artists. Demonstrating, in the path of Brooks, how human nature can be seen to possess the essential characteristics of a machine.
RAP is equipped with a grid of 3x3 color detection sensors, eight obstacle avoidance sensors, a compass, a microcontroller and a set of actuators for locomotion and pen manipulation. The microcontroller is an onboard chip, to which the program that contains the basic rules is uploaded through a PC serial interface.
The algorithm that underlies the program uploaded into RAP’s microcontroller induces basically two kinds of behavior: the random behavior that initializes the process by activating a pen, based on a small probability, whenever the color sensors read white; and the positive feedback behavior that reinforces the color detected by the sensors, activating the matching color pen. These two distinct behaviors are described as modes, the Random Mode and the Color Mode. In the random mode RAP searches for color (chromotaxis). If a sufficient amount is not found (threshold) RAP activates here and there, randomly, a pen stroke choosing also randomly the color and the line configuration. The shape, orientation and extent of these initial lines are determined by the robot based on a random seed acquire from its relative position in the space. This is done with the data retrieved by the onboard compass. In this way RAP’s random generator can be described as real random and not pseudorandom.
When a certain amount of color is detected the robot stops the random behavior and changes to color mode. In this phase RAP only reacts to the spots where a certain amount of color is found, reinforcing it with the same tone.
After a while a discrete pattern emerges, where from a general random background a well defined composition can be recognized.
In order to determine when the painting is finished RAP makes use of a grid of 3x3 RGB sensors. If a certain pattern is found the robot "considers" the work to be done, moves to the down right corner and signs.
RAP creates artworks based on its own assessment of the world. At any given moment the robot "knows" its situation and acts accordingly. It scans constantly the canvas for data retrieving. It uses its relative position in the space as a real random generator. It builds gradually a composition based on emergent properties. It decides what to do and when to do it. It finishes the process using its particular sense of rightness.
Although the human contribution in building the machine and feeding it with some basic rules is still significant, the essential aspects of RAP’s creativity stems from the information that the robot gathers by its own means from the environment. In this sense RAP’s art must be seen as an original creation independent of the human artist that was at the origin of the process.
A new kind of art
My painting robots were created to paint. Not my paintings but their own paintings. The essential of their creations stem from the machine own interpretation of the world and not from its human description. No previous plan, fitness, aesthetical taste or artistic model is induced. These robots are machines dedicated to their art.
Such an endeavor addresses some of the most critical ideas on art, robotics and artificial intelligence. Today we understand intelligence as a basic feedback mechanism. If a system, any system, is able to respond to a certain stimulus in a way that it changes itself or its environment we can say that some sort of intelligence is present. ‘Sheer’ intelligence is therefore something that doesn’t need to refer to any kind of purpose, target or quantification. It may plainly be an interactive mechanism of any kind, with no other objective than to process information and to react in accordance to available output capabilities.
Hence and although my starting point was bioinspiration, in particular modeling social insect’s emergent behavior, the idea was to construct machines able to generate a new kind of art with a minimum of fitness constraints, optimization parameters or real life simulation. It is the simple mechanism of feedback and stigmergy that is at work here.
These artistic robots are singular beings, with a particular form of intelligence and a kind of creativity of their own. They do art as other species build nests, change habitats or create social affiliations. But since we, humans, are for the time being the only pensive observers, the relation between machine art and human aesthetics principles is here the central issue. Many people like the robot paintings, probably because we seem to gladly embrace fractal and chaotic structures. But, more than shapes and colors, what some of us really appreciate in this idea and its associated process, is the fact that it questions some of our most strong cultural convictions. Actually it was supposed art to be an exclusive matter of mankind. In this sense, the robot paintings are a provocative conceptual art that problematizes the boundaries of art as we know it.
 Wiener, N. (1948) Cybernetics; or the Control and Communication in the Animal and the Machine, MIT Press
 von Neumann (1966) Theory of self-reproducing automata, ed. By A.W. Burks, University of Illinois
 Brooks, R., (1991) Intelligence without Reason, Proc. 12th IJCAI, Ed. Morgan Kauffmann, San Mateo and Brooks, R., (2002) Flesh and Machines: how robots will change us, Pantheon Books
 Langton, C. (1987) Proceedings of Artificial Life, Adison-Wesley
 Wilson, Edward O. (2006) Nature Revealed, Selected Writings 1949-2006, The Johns Hopkins University Press, Baltimore
 Grassé, P. P. (1959) La réconstruction du nid et les coordinations inter-individuelles chez bellicositermes natalienses et cubitermes sp. La théorie de la stigmergie: Essai d’interpretation des termites constructeurs, Insectes Sociaux, 6, pp. 41-48
 Moura, L. and Pereira, H.G. (2004) Man and robots: Symbiotic Art, Institut d’Art Contemporain, Villeurbanne
 Breton, André (1969) Manifestoes of Surrealism, University of Michigan Press
Published in Ylem Journal, 2007