divendres, 30 d’octubre de 2009

Towards an Enactive Artificial Intelligence I

Artificial Intelligence (AI) can be approached just with an engineering frame of mind, looking for algorithms that work, being able to solve a problem. However, one can settle to a philosophical one too, and consider AI a conceptual tool to get better insight on what the mind is and how it works. Within that frame of mind, just solving problems is not enough: we want our theory to have, to a certain degree, psychological reality. We want our model to embed some of the earthly properties that human minds have. Nowadays, discussion is mainly around three main models concerning what the mind is: symbolic cognitivism, connectionism and the embodied mind. II adhere to the third model; in particular, to a special branch of it usually known as "enactivism",which I plan to introduce in a short series.


Thousands of pages have already been written about the differences between these three mind models, and which is the superior one. To my understanding, despite their success in creating models on subjects like mathematical reasoning, face recognition, visual perception or even creating artworks, both the symbolic approach or the connectionist one have one major flaw which is of considerable philosophical importance: they can’t produce a credible account of the relationship between mind and world. Being local symbolic representations or distributed subsymbolic representations, both models are based on an abstract reconstruction of a specific domain of the physical world, both the selection and the way representations are connected to real life events and objects has been articulated beforehand by the cognitive system (Thompson 2007). Connectionism tries to generate a more plausible description of the mind, trying to better capture its neurological basis. That leads to a more dymanic account of representations: instead of being something stable, they are distributed along the whole system as well as self-organised, having certain sort of co-variation with the enviroment. However, both symbolic cognitivism and connectionism consider the world and the mind as two completely different entities, with a very much regulated protocol of interaction.

The embodied mind shares some characteristics with connectionism. It also proposes a self-organised system and it is based on a dynamic approach. However, in this approach dynamicism has been extended to the correspondence between mind and world. Instead of having a simple coordinated correspondence between symbols (or subsymbols) and real life objects, the embodied mind paradigm is based in a non-linear causality system in which by means of sensorimotor integrations, brain, body and enviroment are continuously influencing one another, making it impossible to separate the three into clear-cut parts. In order to have such a system, it is basic that the cognitive entity has some sort of “body” that can obtain continuous information from the real world in order to co-vary and co-adapt with it (Thompson 2007). This is why the paradigm we are discussing is usually called “the embodied mind”. First of all we need to avoid the tendence to interpret the concept of “embodied mind” in its weakest sense: that this, a mind needs a body. The embodied mind paradigm argues for something a lot stronger than that, mainly: mind is just the result of circular and continuous process of causality between brain activity, body and environment, with no possibilities to make a clear distinction among then, nor a chance to build a theoretical model in which mind can be described autonomously from body and environment. (Pfeifer and Iida, 2005).


The embodied mind paradigm is based on the following ideas (Varela, Thompson, Lutz, Rosch 1991):

1) Living beings are autonomous entities and are responsible for their own goals, they are not just settled from the outside.

2) The nervous system is also an autonomous entity, which takes care and is responsible of keeping its own coherent and meaningful patterns.

3) Cognition is the skillful know-how that co-varies with environment and how it evolves. Every cognitive action is both situated and embodied.

4) Cognitive processes are not formally prespecified, but relational domains continually coupling with the environment.


A large amount of the literature takes living beings as the main metaphor. In their seminal book, Varela et al (1991) developed most characteristics of their model by analysing the way cells behave and “represent” environment. Nevertheless this shouldn’t be considered a vitalist model, defending that only living beings can achieve real consciousness. Continuous coupling with the environment and self-established goals are the only requierements, as it is shown in the aforementioned book when Varela et al. argues in favour of how relevant Brooks’ robots are, presenting them as artificial systems that have some of the main characteristics of an embodied mind (Brooks 1991). In the next post I to show how the enactive approach can greatly improve current research in AI that also looks for psychological realism and relevance.


References


Brooks, R. A. (1991), “Intelligence without representation”, Artificial Intelligence, 47(1-3), pp. 139- 160
-- (1999) Cambrian Intelligence: The Early History of the New AI, MIT Press, Cambridge, MA

Pfeifer, R. and Iida, F. (2005). Morphological computation: Connecting body, brain and environment. Japanese Scientific Monthly, Vol. 58, No. 2, 48-54

Thompson, E. (2007) Mind in life, Cambrigde (Mass), Harvard University Press.

Varela, F. J., Thompson, E. Lutz, A. Rosch, E. (1991) The embodied Mind: Cognitive Science and Human experience. Cambridge (Mass), MIT Press.