Biologically Inspired Cognitive Architectures (2016) 16, 169– 178

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INVITED ARTICLE Origins and evolution of enactive : Toward an enactive

Leonardo Lana de Carvalho *,1, Denis James Pereira 2, Sophia Andrade Coelho 3

Federal University of Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil

Received 1 September 2015; received in revised form 14 September 2015; accepted 24 September 2015

KEYWORDS Abstract Cognitive science; This paper presents a historical perspective on the origin of the enactive approach to cognitive Enaction; science, starting chronologically from , with the aim of clarifying its main concepts, Complex systems; such as enaction, , structural coupling and natural drift; thus showing their influ- Cognitive architecture ences in computational approaches and models of cognitive architecture. Works of renowned authors, as well as some of their main commentators, were addressed to report the develop- ment of enactive approach. We indicate that the enactive approach transcends its original con- text within biology, and at a second moment within , changes the understanding of the relationships so far established between the body and the environment, and the of conceptual relationships between the and the body. The influence on computational the- ories is of great importance, leading to new artificial intelligence systems as well as the propo- sition of complex, autopoietic and alive machines. Finally, the article stresses the importance of the enactive approach in the design of agents, understanding that previous approaches have very different cognitive architectures and that a prototypical model of enactive cognitive architecture is one of the largest challenges today. Ó 2015 Elsevier B.V. All rights reserved.

* Corresponding author. E-mail addresses: [email protected] (L.L.d. Carvalho), [email protected] (D.J. Pereira), [email protected] (S.A. Coelho). 1 Professor Leonardo Lana de Carvalho critically analyzed and improved the historical overview, leading to enactive cognitive architectures. 2 Denis James Pereira created the first version on the historical overview on origins of cybernetics and enaction. 3 Sophia Andrade Coelho collaborated with domains of language as complex systems. http://dx.doi.org/10.1016/j.bica.2015.09.010 2212-683X/Ó 2015 Elsevier B.V. All rights reserved. 170 L.L.d. Carvalho et al.

Introduction canson (1709–1782) who urged his spectators to think about the human only as a very complex mechanical system. The zeitgeist involving natural philosophy, materi- Cognitive Science is an interdisciplinary field and its stud- alism and mechanism have enabled the development of ies involve several areas of cognitive thought. The cogni- cognitive science. Nevertheless, landmarks of enormous tive perspective is presented in many disciplinary sectors importance to the achievement of these sciences are Alan such as biology, education, , neurosciences, phi- Turing’s work (1912–1954). Turing published in 1936 the losophy, , anthropology, sociology, artificial paper ‘‘On Computable Numbers, with an application to intelligence, as well as knowledge engineering, ergonomics the Entscheidungsproblem”, and a correction in 1937, in and human and social sciences. The methodological frame- which he exposes his machine. The allowed work of cognitive science is research on the mind, cogni- to instantiate logical-mathematical operators in the tion and behavior through computational models. machine and the manipulation of symbols through an algo- Theories, models and computational implementations form rithm in a limited and unambiguous system. Indeed, the a methodological triad on the basis of all cognitive investi- view of Turing about the mind was nothing but a kind of gation (Carvalho, Varenne, & Braga, 2014). This paper mechanical procedure (Turing, 1950). Cybernetics as a intends a historical presentation of the origin and evolu- social movement is considered to be the first academic dis- tion of enactive thought within the cognitive sciences, cussion on the investigation of the mind/brain activity with focusing on some of the major works in the area, related logic-mathematical procedures (Silva, 2007). The Turing authors, and some of the scientific events of great impor- machine was the main influence for such debates and aca- tance for the consolidation of the cognitive science.4 We demic discussions. Warren McCulloch and also start chronologically from cybernetics, with the aim of contributed greatly to the development of cognitive clarifying essential concepts, such as enaction, autopoi- sciences. In 1943, they published the article ‘‘A logical cal- esis, structural coupling and natural drift. Thus showing culus of the ideas immanent in nervous activity”, which their influences in computational approaches and modeling was considered another landmark for this interdisciplinary cognitive architectures. science. It is interesting to start the historical overview5 saying With increasing interest in cybernetics issues, the cog- that cognitive science is embedded in natural philosophy nitivism was founded in 1956 at the Symposium on Infor- and this maintains strong types of mechanical thinking mation Theory, held at the Massachusetts Institute of today. A landmark of mechanicism we can say is the Technology. The great diversity of theoretical and Digesting Duck built in 1739 by the engineer Jacques Vau- methodological possibilities of cybernetics has been reduced or translated in the hypothesis of as 4 Seeking to highlight the interesting paths which led to the theory physical symbol systems. Despite the great importance of enaction, we call the reader’s attention to classic works of of , several objections arise to this thought; cognitive science. We seek to contextualize them with the the most widespread is the Chinese Room of John publication dates, full titles already inside the text since these R. Searle. After more than twenty years of cognitivism title are highly relevant and also mentioning academic events that domain (Varela, Thompson, & Rosch, 1991/2001), impor- occurred at that , etc. What perhaps may be surprising to some tant discoveries have led to the and consolida- people, is trying to show the history of science not only as a rational enterprise, ie, independently of the social body which accomplishes tion of connectionism. We highlight three relevant works: ” this individual activity (Laudan, 1977). Some authors, works and ‘‘ of Rosemblatt (1962); ‘‘Neural networks concepts are shared by approaches, however they diverge notori- and physical systems with emergent collective computa- ously. We seek to present cognitive science not only as a tangle tional abilities”, a work on neural network, written in rational discourse on the mind, but also as an academic social 1982 by John Hopfield, and the work ‘‘Computer Vision” movement, dynamic and non-linear. published in 1982 and developed by Dana Harry Ballard 5 In relation to its historical aspect, this research follows the and Christopher M. Brown. precepts of the theory of scientific growth of Laudan (1977, 1984). Thus, this article presents the progressive context of Laudan preserves scientific rationality and progress but shows that the enactive approach to cognition from the develop- this is of great social influence, varying in function of social ment of the preceding cognitive approaches. Further- movements, especially academic networks. We can say that this social embodiment leads the process of evolution of science to more, the article focuses on the discussion of the numerous non-linear movements, which according to Laudan, can enactive approach and a brief analysis of its influence be best studied by cognitive sociology. Understanding how this in the renewal of computer models and cognitive archi- social research activity is organized can enable better understand- tectures. Varela et al. (1991/2001) present the history ing about how individuals and scientists draw their ideas, compre- of cognitive science as a normal science demarche, pro- hending better scientific growth. We invite the reader to scan the moting theoretical advances with knowledge accumula- history of cognitive science and observe in details more than simple tion. The enactive theory is seen as the third way, noises, but possibilities of realization. We argue that there have followed by cognitivism and connectionism, respectively. already been some instigating enactive notions in cybernetic fields, We are sure that the misunderstanding about these pre- but at that time, researchers evolved in academic networks were vious approaches of cognition can profoundly deny any not able to realize some concepts and procedures. Similarly, complex systems notions have occurred in the cognitive science, understanding of what the enactive cognitive science is, and prominently on the enactive theory of cognition, but only by and its future development. This article proposes to the end of the nineties they have been presented as a research bring out the history of cognitive science focusing on perspective on cognition and pointing innovations in the design of some foundations works of the different proposals of cognitive architectures. cognitive architectures. Origins and evolution of enactive cognitive science: Toward an enactive cognitive architecture 171

Cognitive approaches before enaction biological system. However, they are clearly different the cognitivist and connectionist methods of studying cog- nition. The connectionist method is biologically inspired; Cybernetics is the first academic social movement aimed it seeks to artificially synthesize biological structures, per- at discussions on computational perspective on the mind, mitting the emergence of cognitive actions. The cogni- however, some cognitivists and connectionists often tivist approach proposes to build programs based neglect it. Despite this fact, many of its ideas are com- directly on how human think in their solving- monly used in everyday life. Some examples are the problems activities. thoughts of life and mind based on process- Cognitivism has some characteristics listed as problems ing machines, that would later lay the groundwork for by its critics. According to Searle (1996/2010), the most the foundation of artificial intelligence (AI); the interdis- famous objection was formulated in 1980, in his article ciplinary study of ; self-organizing sys- ‘‘, brains and programs”, which is known as the argu- tems, and also the use of mathematical logic for the ment of the Chinese room. The experiment of the Chinese understanding of the nervous system. The main objective room consists of a person locked in a room, with access to of cybernetics was to become a new science of the mind a book containing rules written in Chinese, but this person (Dupuy, 1994/2009; Silva, 2007; Varela et al., has no knowledge about the language. These rules tell the 1991/2001). person what to answer when receiving words written in Chi- Its origin is commonly dated in 1943 with the publication nese, such as if you receive x, then answer y. The person in of two articles. First, ‘‘A logical calculus of the ideas imma- the room receives slips of paper written in Chinese, and nent in nervous activity” written by the authors Warren then checks the book to find the right answer in Chinese, Sturgis McCulloch and Walter Pitts, and the second, entitled only by following the instructions. The people who sent ‘‘Behavior, Purpose and ”, written by Arturo and received the strips out of the room noticed that the per- Rosenblueth Stearns, and Julian Bigelow.6 son in the room served their purpose by responding cor- In the 1980s, connectionism retrieves the first text as the rectly to the questions, but this person had no most important landmark of this approach, showing the understanding about Chinese or what was written, stresses resumption of cybernetics at connectionism. Another land- Searle. As a machine, the person inside the room has just mark of cybernetics is The Macy Conferences, written manipulated the symbols, following the rules. In this sense, between the years 1946 and 1953 in New York under the according to Searle (1980), the machine is semantically organization of the Josiah Macy, Jr. Foundation, all chaired empty, operating with the language only with its syntactic by Warren S. McCulloch. and lexical dimensions. In 1956, the MIT Symposium on However, Casti (1998) argues against the conclusions held in Cambridge in the United States, can be regarded drawn by Searle from his allegory. The first entitled ‘‘The as a founding moment of cognitivism. Herbert Alexander Luminous Room Argument” was created to say that before Simon, Noam Chomsky, , Allen Newell, Jerry Maxwell (1831–1879), electricity and magnetism were con- Alan Fodor and John McCarthy presented guidelines for sidered to be forces unrelated to luminescence phe- this theory in cognitive science at the symposium. Some nomenon. However, this turned out to be incorrect works from these authors like McCarthy (1959), Chomsky because electromagnetism spreads at lightning speed. (1968), Newell & Simon (1976), Holland (1975, 1995), Light, electricity and magnetism did not seem to be associ- Fodor (1983) and Minsky (1986) came to be very important ated, as occured for Searle with the lexical, syntaxical and on the history of cognitive science. In the most expressive semantical aspects of language. Previously used by works of cognitivism is evident the possibility of building Haugeland (1982), this argument shows that intelligence in computational models to investigate the human cognition, general and semantics are not internal characteristics of but is evident, above all, the cognitive of com- the Turing machine or the , but relational char- puter architectures (see Newell & Simon, 1976; acteristics. The embodied semantics emerges from the Pylyshyn, 1984). ‘‘The psychological observations and interactions of the organism with the environment and par- experiments lead to the formulation of hypotheses about ticularly the relation with other organisms. Thus, looking at the symbolic processes the subjects are using, and these the interior of the room, we can only find a semantically are an important source of the ideas that go into the con- empty piece (Casti, 1998; Haugeland, 1982). The solutions struction of the programs.” (Newell & Simon, 1976, pp. suggested by Haugeland and Casti find a very fertile ground 119–120). Despite the focus on higher cognitive abilities, in enactive theory, as we will explore further. We believe cognitivism understands the human being strictly as a that future research will find a fertile ground for the design of cognitive architecture at the crossroads between the 6 Rosenblueth, Wiener, and Bigelow (1943) emphasize that tele- concept of semantics in the second Wittgeinstein and in ology should be interpreted as a purpose controlled by feedback and enactive theory. according to this definition, teleology is not opposed to determin- We may say that connectionism is a recovery in cyber- ism, that is, natural . In Aristotelian tradition, teleology netic thinking. For the emergence of enactive theory, it has been interpreted to imply final cause and this concept of final is important to emphasize main concepts such as self- causes has led to the opposition of teleology to . We can say that authors argue that organisms are a kind of machine organization, emergence and properties. Connectionist acting by positive and negative feedback. These ideas are quite architecture consists on a setting of information process- interesting as an enaction theory precursor because they explain ing units, representing , people, etc. Cognitive that actions are self-regulated through organism’s interactions with actions are described in terms of the dynamic or the environment. functionality of the units while they interact with the 172 L.L.d. Carvalho et al. environment and themselves. The ‘‘Hebb’s rule” pro- tionists show that the properties of memory in the brain posed by Donald Hebb (1904–1985) in his book ‘‘The are clearly emerging properties of neural networks Organization of Behavior: A Neuropsychological Theory” (McCulloch & Pitts, 1943; Rosenblatt, 1962; Rumelhart from 1949, describes one of the most important rules & Norman, 1981; Hopfield, 1982; Smolensky, 1994). Five of learning by connectionist architectures; the rule says arguments were listed by Rumelhart (1998): when a that when there are more active interactions, the con- familiar comes to mind it is expanded and the nection becomes stronger. response is strong; when a stranger pattern comes to In 1943, Warren S. McCulloch and Walter Pitts published memory the activity is reduced; when only a part of the article: ‘‘A logical calculus of the ideas immanent in the learned external pattern arrives to memory, it can nervous activity”. In this article, they proposed that the still responds through a reconstruction process; when a functioning of neurons is quite simple and that their com- similar pattern to a learned pattern comes to memory, plex processes are generated from the connection with the neural network responds by distortion, proceeding other neurons.7 This is a very important , anticipating not by differentiation, but it responds as if that was the enaction because it believes that simple causes can lead the familiar pattern; if multiple are learned, to complex effects solely by the interaction. John von Neu- the memory system will still responds with a central ten- mann in 1948 in Hixon Symposium, held in Pasadena, Cali- dency with new or familiar input pattern. Memory cre- fornia, gave a presentation titled ‘‘The General and ates a prototype, even if the standard prototype has Logical Theory of Automata”. In this presentation, von never been presented before as an input. However, an Neumann (1951) claims, despite some criticism about the artificial neural network does not always make correct model of McCulloch and Pitts, that it is important to make generalizations, like humans. The term ‘‘auto- simple architectures and explained the ‘‘self-reproduction associative memory” refers to the capacity to reconsti- theorem”. Another important landmark of connectionism tute the whole, the entire pattern from a piece of infor- was Perceptron, first exposed by in 1957 mation. It is not necessarily our aim to stress even more on an IBM 704 and published in 1962 at ‘‘Principles of Neu- here the fundamental importance of these and others rodynamics: Perceptron and the theory of brain connectionists works as the basis of autopoietic reasoning mechanisms”. on cognition. In fact, the development of the enactive Jerome A. Feldman and Dana Harry Ballard, in 1982, research of the memory owes much to connectionism proposed the term ‘‘connectionism” for this new (see Rosch, 1983). approach, in the article ‘‘Connectionist models and their We understand that connectionism is the second most properties”. Feldman and Ballard presented one of the important theory for the rise of enaction thought, while clearest expositions about the architecture of connection- the first one would be the evolutionary biology. Varela ist agents. Connectionist considers that single units, when et al. (1991/2001) said their research were firmly feet connected, can generate emergent pattern on the net- planted in cognitive science when seeking inspiration in work, with their own emergent characteristics, just by the phenomenological thought. We argue that one foot is being connected. In addition to the numerous models of stuck in evolutionary biology and another in connectionism; neural networks, the cellular automata model can also this is the support of the naturalization movement of mind be considered a variation of connectionist architecture. led by enactive theory of cognition. Automata cellular are an ensemble of simple units with a random or predetermined initial state where each unit receives inputs from neighbors and displays the outputs Enactive approach to cognitive science to them. Consequently, the particular unit responses inevi- tably influence the ones of their neighbors, creating an The enactive thought in cognitive sciences is developed and interconnected network and a self-organized system based on one of the main features of connectionism: self- (Wolfram, 1984). organization. The concept of self-organization has become Other contributions to the connectionist model were more systematically investigated in several contributions. performed by Rumelhart, McClelland, and the PDP We can list the works of , especially Research Group (1986) in their books ‘‘Parallel Distribu- ‘‘General System Theory: Foundations, Development, Appli- ted Processing: Explorations in the Microstructure of Cog- cations” published in 1968, and the introduction of the nition”. After Carey (2011), this work on computer strange attractor, written by Edward Norton Lorenz in simulations of gave to cognitive science some 1963, entitled ‘‘Deterministic nonperiodic flow”. In addi- of the first testable models of neural processing. Connec- tion, the works of Benoit Mandelbrot, mainly ‘‘Fractals: Form, Chance and Dimension” published in 1977, and the 7 In the excerpt below transcribed we can also clearly see the idea work of Marvin Lee Minsky, especially the book released in of embodied mental functions, as self-organized configurations 1988, ‘‘The Society of Mind” have collaborated to diversify emerging by the stimulation activity. ‘‘The nervous system contains the scientific communities in cognitive science, pointing many circular paths, whose activity so regenerates the excitation of possible future innovations in the domain. We argue that any participant that reference to time past becomes the enactive theory is a convergence or a translation of this indefinite, although it still implies that afferent activity has realized rich moment. one of a certain class of configurations over time. Precise specification of these implications by means of recursive functions, We can say that the concept of enaction would provide a and determination of those that can be embodied in the activity of naturalistic alternative, strongly connected with biological nervous nets, completes the theory.” (McCulloch & Pitts, 1943, p. scientific thinking and connectionism. According Sebbah 117). (2004) the phenomenological thought have been essentially Origins and evolution of enactive cognitive science: Toward an enactive cognitive architecture 173 an example and incentive for the cognitive science trajec- Thompson and Heider, the authors emphasize tory.8 Many consider Romesı´n a mem- the importance of thinking in a computer model to discuss ber of a group of second-order cyberneticians, such as von the concepts of the theory. The architecture used in the Foerster (1949). He has proposed in 1970 the report ‘‘Biol- work to generate emergent patterns and structural coupling ogy of Cognition” to the Biological Computer Laboratory is the Bittorio agent. The Bittorio is a set of cells in which of the University of Illinois (Maturana, 1970). Proposed as each cell has its own state, ranging from 0 to 1, calculated an approach to cognitive science, we have the improvement on the state of cells around them. It has a ring-shaped and of this text, ‘‘Biology of Cognition” by Maturana with Fran- receives external perturbations. These perturbations lead cisco Varela Javier Garcia, which gave rise to the book to a change in the state of the affected cells, so they pass ‘‘Autopoiesis and Cognition: The Realization of the Living” through a transformation of the emergent pattern. It is (Maturana & Varela, 1980). One of the most exciting texts observed in this type of system that some emerging patterns about enactive theory of cognition is undoubtedly in the remain, because calculated cell values are created accord- book ‘‘The tree of knowledge. Biological basis of human ing to the values of neighboring cells, caused by the self- understanding” published in 1984 by Maturana and Varela. organization of the system. It is also noteworthy that the The enactive approach is rooted in the concept of autopoi- responses issued by Bittorio are much more dependent on esis (‘‘auto” meaning ‘‘self” and ‘‘poiesis” meaning ‘‘pro- emerging internal patterns than they are from the perturba- duction”). The living being is presented to be a producer tion. The response cannot be considered in a linear relation- of itself. This is only possible with beings that produce the ship with the stimulus (perturbation), neither can this conditions of their own . The environment modi- perturbation be considered as information used at deduc- fies or perturbs a structure whose function keeps this struc- tion or inference operations from the cognitivist ture. In this sense, the living entity is described as a history architecture. of perpetuating in the world that takes place through its Structural coupling is an important concept for ena- structural coupling and its operational closure. The evolu- tivism, ‘‘... interactions (once recurring) between unity tion of the species occurs by means of a natural drift, while and an environment consist of reciprocal disturbances. In natural selection is a consequence of it. Maturana and these interactions, the environmental structure only trig- Varela (1984/1995) have argued that evolution itself can gers structural changes on autopoietic units (do not deter- be thought of as natural drift, which is the mechanism mine or inform), and vice versa for the environment.” responsible for rising diversity of living systems. In this (Maturana and Varela, 1984/1995, p. 113). way, natural selection is a consequence of the constitution The main issue about the conceptualization of autopoi- of the biosphere through natural drift. esis, according to Maturana and Varela (1984/1995) and Mark L. Johnson, with his book ‘‘The body in the mind: Maturana and Mpodozis (1992/1999), is constructed with The bodily basis of Meaning, Imagination, and Reason” the dialogue including the evolutionary theory of Darwin. (1987) and George Lakoff with the book ‘‘Women, fire, To be in a process of natural selection, would not be and dangerous things: What categories reveal about the required before one simply exists? So, what is it to be alive? Mind” (1987) also have contributed to the rise of enac- When comparing a living being with a material that is tivism. They emphasize that the source of intelligence is not alive, we proceed by examining a distinction between in the body in action, and stressed the of cognition: the two. For example comparing an animal, such as a to be in action (‘‘en accio´n”). cow, and an object such as a chair: this act of distinction The enactive approach is receiving significant influence leads us to consider both the cow and the chair as units. from connectionism, especially regarding the concepts of Considering that the cow is a living being, what is the essen- self-organization and emergent properties. In the book pub- tial characteristic that defines this condition? Until the the- lished in 1991, ‘‘The Embodied Mind: Cognitive Science and ory was established, there were several proposals to the human ” written by , Evan definition of an alive being, such as reproduction, move- ment, chemical composition or a list of all the previous 8 The work of Maurice Merleau-Ponty is of great importance to the ones, but these definitions all have conceptual problems. naturalization of phenomenology. We highlight the book ‘‘La Although the features list becomes greater; it would remain structure du comportement” originally published in 1942. We could limited, unless it includes all living beings. The definition of notice that, while Merleau-Ponty still creates a dialogue between phenomenology and , according to Bouyer (2014),‘‘... structure and organization collaborated to understand the this naturalization of the husserlian phenomenology, which gains condition of being alive. A chair, for example, may have force in philosophy and Cognitive Science, had its starting point in the following structure: back, seat and legs. The structure, the phenomenology of Merleau-Ponty” (p. 444). The wide gap that thus, consists of the components or the of the separates cognitivism and phenomenology had begun to be reduced unit. The structure needs an organization, meaning the rela- when approaching the reality of human consciousness and its tionship that must occur between the structural elements physical and chemical properties (Brown, 2008). However, De for that particular unit that belongs to a specific class. For Castro and Gomes (2008) emphasize that any form of naturalization a chair, for example, there is no importance in its composi- of phenomenology will be widely different from phenomenology. In tion if it’s metal, wood or glass, but the organization of its the Hubert Dreyfus Lederer’s work ‘‘What computers can’t do: a structure matters so that it can belong to the class of chairs. critique of artificial reason” from 1972 we have a dialogue between cognitivism and phenomenology. Dreyfus (2007) seeks to explain So what is the essential organization of every living being? the reasons for the failure of his ‘‘Heideggerian Artificial Intelli- The answer that sums up a whole list of concepts is autopoi- gence” suggesting that for reasoning ‘‘... one does not need a esis (Maturana and Varela, 1984/1995). In order to maintain mental representation of one’s goal nor any subagential problem internal dynamic, the cell correctly continues with its meta- solving.” bolism and it the border allows it to adapt to the limited 174 L.L.d. Carvalho et al. space in the cell. This limited space, called membrane, was development of simple autonomous systems forming developed from its own internal relations of cellular meta- dynamic/social structures situated in an environment. This bolism. ‘‘... on one hand, we see a network of dynamic development can be well understood in Brooks’ work and changes that produce their own components and which is mainly in his articles ‘‘Achieving artificial intelligence the condition of possibility of the border, on the other, through building robots” written in 1986, ‘‘Intelligence we see a border that is the condition of possibility for the without representation” (1991), and ‘‘Intelligence without operation of the network transformations that produced reason” (1991), that propose the construction of mobile as a unit.” (Maturana and Varela, 1984/1995, p. 85). robots not by the division function, but by activity The evolution as natural drift means that, before the decomposition. organism can undergo a selection process, it must be self- Brooks’ contributions are landmarks of new directions for producing in an environment. This is its challenge: to be AI, especially for behavior-based robotics. Another expo- alive. ‘‘The maintenance of organisms as a dynamic system nent of this robotics field is Luc Steels, currently director in their milieu depends on compatibility between organisms of the Artificial Intelligence Laboratory of the Vrije Univer- and the environment, what we call adaptation.” (Maturana siteit Brussel. The behavior-based robotics is a field of and Varela, 1984/1995, p. 137). If the organism produces research initially more connected to the first reinterpreta- itself in an environment, this organism is adaptive and its tions of behaviorism, with the theory of information or actions are described as cognitive. We should notice that the theory. The main purpose is con- changes in the environment are critical to the adaptability, ceiving computational models of behavioral learning mech- and then, a selection process might emerge.9 Maturana and anisms, notably the respondent conditioning and operant Varela (1984/1995) have argued that evolution itself can be conditioning. thought of as natural drift. Natural drift as the mechanism Like Brooks (1986, 1991a, 1991b), Steels continues to sig- that gave rise to the diversity of living systems means that nal the transition from this behavioral-cognitive theory to the organism and the medium maintain congruent structural the enactive theory of cognition. We argue that, in fact, changes. Life exists due to this conservation of dynamic Steels and some other authors have started a movement structural congruence between organism and niche. In this beyond the enactive theory of cognition, initiating a com- way, natural selection is a consequence of the constitution plex systems perspective of cognition. Steels’ research has of the biosphere through natural drift. contributed to the creation of the Sony AIBO in 1999, and other later robots, such as Sony QRIO. He has also high- Influences of enactive theory on lighted the studies on natural language. His articles on the computational thought development of language, such as ‘‘Language as a Complex Adaptive System” from 2000, presents language as emerging from a complex network of interactions, conceived from the In 1992, Francisco Varela and Paul Bourgine (honorary direc- interaction of agents with their environment. We under- tor at RNSC in the French National Network of Complex Sys- stand that another important article was published in 10 tems ) organized the book ‘‘Toward a Practice of 2003, titled ‘‘Intelligence with representation”. In this Autonomous Systems: Proceedings of the First European paper, the author opposes Brooks, explaining that a semi- ” 11 Conference on Artificial Life . Among the researchers otic notion of representation should be maintained. We directly involved in the event, we can point to Domenico believe that this is an important landmark for reaching Parisi, John Henry Holland, Rodney Allen Brooks and maturity of complex systems approach to cognition. Christopher Gale Langton. On the website of the Interna- Mitchell (1998), in the article ‘‘A complex-systems perspec- tional Society for Artificial Life there is a wide repertoire tive on the ‘computation vs. dynamics’ debate in cognitive of evidence of the renewal of computational concepts under science” argues that ‘‘Most of these theories assume that the influence of enactive theory. Several texts address information processing consists of the manipulation of genetic algorithms, autonomous agents, emergent behav- explicit, static symbols rather than the autonomous interac- ior, neural networks, etc. tion of emergent, active ones.” (p. 715). The main influence of enactive theory in computational Indeed, emergent signs, or emergent representations, thinking is the renewal of artificial intelligence that are a sensitive matter and we would not have the space here explores the concept of structural coupling. As we have to address this issue properly. However, we would like to emphasized in this article, the disturbances of the environ- notice that nowadays, it is an aspect that divides the com- ment trigger changes in the organization of the autopoietic munity in embodied cognitive sciences, and it may even be being and vice versa. Therefore, research on AI led to the signaling a transition to a complex systems theory of cogni- tion (see Fig. 1). We argue that the dynamical approach to 9 Evolution itself is not a simple matter, we will not have space mind is part of this transition (see specially Thelen & and it is not our aim here to continue to develop the theme more Smith, 1993; van Gelder & Port, 1995). The cognitivist and broadly. Our suggestion is to read the text of Maturana and connectionist theories have prototypical models of cogni- Mpodosis (1992/1999), which deals with the theme very deeply. tive architectures for their intelligent agents, while enac- 10 This event is part of a historical process quite interesting to tive theory doesn’t have its prototypical model. indicate a deep involvement between enaction and complex systems in scientific research organizations in France. Crutchfield (1994) understands that new machine architec- 11 For more information about the European Conference on ture is required to investigate the emergence and complex Artificial Intelligence visit the website of the International Society systems. According to the author, the complex systems for Artificial Life available at: . Accessed approach of the machine consists of a particular 01/12/15. notion of structure. The complex machine structure would Origins and evolution of enactive cognitive science: Toward an enactive cognitive architecture 175

Fig. 1 Conceptual map of the state of cognitive science with some historical landmark books and the main approaches. Cognitivism and connectionism, respectively, give the support in terms of scientific knowledge to the largely cognitive technologies available to society. We argue that an enactive cognitive architecture is currently the great challenge of cognitive science. However, its achievement can mean a ripe transition to a complex systems approach to cognition, reviewing notions of ‘‘representation”, ‘‘symbol” and ‘‘information”, proposing a new analysis around the concepts of emergent signs and complex computing machinery. be based on a ‘‘nonlinear mechanical computing pro- Conclusions cesses”. This malleable structure can be modified by means of mechanisms for transformation of the structure. These This paper presented a short historical overview on the ori- mechanisms of transformation would lead to a constant gins of the enactive cognitive science, focusing on some of ‘‘reconstruction of the hierarchical machine” by itself. To the major works in the area, the related authors, and some connect the structural reconstruction processes, Crutchfield of the scientific events that were of great importance for provides ‘‘evolutionary mechanics”. Then, he suggests that the consolidation of the cognitive science. Starting chrono- this complex machine should be the standard model for the logically from cybernetics, we have aimed to clarify the study of complex systems and emergence. In this sense, it main enactive concepts, such as enaction, autopoiesis, may be instructive to follow the criticism of Thompson structural coupling and natural drift (this concept being that (2007) to the concept of emergent properties and his which reviews and gives another context to the classical defense of emergent processes to recover a way of thinking concept of natural selection), thus showing their influences very close to that of Crutchfield. in computational approaches and models of cognitive archi- Any cognitive architecture to be inspired by the enactive tecture. Works of renowned authors, as well as some of cognition theory must actually have the structure coupled their main commentators, were addressed to report the to the environment, it needs to be an autopoietic machine, development of enactive approach. We indicate that the and thus pass its path through natural drift. Following Fodor enactive approach transcends its original context within (2000), perhaps the investigation of this reality is not inter- biology, and at a second moment within connectionism, it esting for some cognitive engineers. However, this research changes the understanding of the relationships so far estab- is profoundly important to cognitive science and the philos- lished between the body and the environment, and the ophy of mind. We argue that technological applications will ideas of conceptual relationships between the mind and surpass the expectations. 176 L.L.d. Carvalho et al. the body. The influence on computational theories is of According to Steels (2003), this B can also be useful to agent great importance, leading to new artificial intelligence sys- architectures, as emergent signs in semiotic relationships tems as well as the proposition of complex, autopoietic, and under the aegis of cross or multi-scale levels of structural alive machines. coupling processes. We stress the importance of enactive The article have stressed the importance of the enactive approach in the design of agents, understanding that previ- approach in the design of agents, understanding that previ- ous approaches have very different cognitive architectures ous approaches have very different cognitive architectures and that a prototypical model of enactive cognitive archi- and that a prototypical model of enactive cognitive archi- tecture is one of the major challenges today and its achieve- tecture is one of the largest challenges today. For the future ment can mean a ripe transition to a complex systems of cognitive science we have pointed that, such as connec- approach to mind. tionism have created a propitious context to the emergence of the enactive theory of cognition highlighting self- organization, emergent properties and so on, in the same way enactivism has created an enabling context to the Acknowledgments emergence of one complex systems approach of cognition, what we have indicated in the works of Crutchfield (1994), This work was supported by the Brazilian Conselho Nacional Mitchell (1998), Steels (2000, 2003) and Rocha and Hordijk de Desenvolvimento Cientı´fico e Tecnolo´gico (CNPq), the (2005). Concerning the development of this complex sys- Fundac¸a˜o de Amparo a` Pesquisa do Estado de Minas Gerais tems perspective see for example Ellis and Larsen- (FAPEMIG), and by Coordenac¸a˜o de Aperfeic¸oamento de Freeman (2009), Mitchell (2009) and Holland (2012). Pessoal de Nı´vel Superior (CAPES) in the context of the Our goal was to clarify the great importance of enactive Brazilian Young Talents Program for Science. concepts through by analyzing several areas of knowledge, focusing on AI with the embodied artificial intelligence. The enactive theory of cognition provided a portal for the References design of new biologically inspired cognitive architectures. Ballard, D. H., & Brown, C. M. (1982). Computer vision. New York: The current traditional opposition between reactive agents University of Rochester. and cognitive agents, circulated by Russell and Norvig Bertalanffy, L. (1968). General System theory: Foundations, (1995), has enriched the research community on enactive development, applications. New York: George Braziller. agents models. The challenge of conceptualizing enactive Bouyer, G. C. (2014). A naturalizac¸a˜o da fenomenologia pelas cognitive architectures is present in Varela et al. cieˆncias cognitivas contemporaˆneas. 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