Agent Theories, Architectures, and Languages: A Survey <s> Brooks -behaviour languages <s> There is an alternative route to Artificial Intelligence that diverges from the directions pursued under that banner for the last thirty some years. The traditional approach has emphasized the abstract manipulation of symbols, whose grounding in physical reality has rarely been achieved. We explore a research methodology which emphasizes ongoing physical interaction with the environment as the primary source of constraint on the design of intelligent systems. We show how this methodology has recently had significant successes on a par with the most successful classical efforts. We outline plausible future work along these lines which can lead to vastly more ambitious systems. <s> BIB001 </s> Agent Theories, Architectures, and Languages: A Survey <s> Brooks -behaviour languages <s> Brooks, R.A., Intelligence without representation, Artificial Intelligence 47 (1991) 139159. Artificial intelligence research has foundered on the issue of representation. When intelligence is approached in an incremental manner, with strict reliance on interfacing to the real world through perception and action, reliance on representation disappears. In this paper we outline our approach to incrementally building complete intelligent Creatures. The fundamental decomposition of the intelligent system is not into independent information processing units which must interface with each other via representations. Instead, the intelligent system is decomposed into independent and parallel activity producers which all interface directly to the world through perception and action, rather than interface to each other particularly much. The notions of central and peripheral systems evaporateeverything is both central and peripheral. Based on these principles we have built a very successful series of mobile robots which operate without supervision as Creatures in standard office environments. <s> BIB002 </s> Agent Theories, Architectures, and Languages: A Survey <s> Brooks -behaviour languages <s> Computers and Thought are the two categories that together define Artificial Intelligence as a discipline. It is generally accepted that work in Artificial Intelligence over the last thirty years has had a strong influence on aspects of computer architectures. In this paper we also make the converse claim; that the state of computer architecture has been a strong influence on our models of thought. The Von Neumann model of computation has lead Artificial Intelligence in particular directions. Intelligence in biological systems is completely different. Recent work in behavior-based Artificial Intelligence has produced new models of intelligence that are much closer in spirit to biological systems. The non-Von Neumann computational models they use share many characteristics with biological computation. <s> BIB003
Probably the most vocal critic of the symbolic AI notion of agency has been Rodney Brooks, a researcher at MIT who apparently became frustrated by AI approaches to building control mechanisms for autonomous mobile robots. In a 1985 paper, he outlined an alternative architecture for building agents, the so called subsumption architecture  . The analysis of alternative approaches begins with Brooks' work. In recent papers, BIB001 BIB002 BIB003 , Brooks has propounded three key theses: 1. Intelligent behaviour can be generated without explicit representations of the kind that symbolic AI proposes. 2. Intelligent behaviour can be generated without explicit abstract reasoning of the kind that symbolic AI proposes. 3. Intelligence is an emergent property of certain complex systems. Brooks identifies two key ideas that have informed his research: 1. Situatedness and embodiment: 'Real' intelligence is situated in the world, not in disembodied systems such as theorem provers or expert systems. 2. Intelligence and emergence: 'Intelligent' behaviour arises as a result of an agent's interaction with its environment. Also, intelligence is 'in the eye of the beholder'; it is not an innate, isolated property. If Brooks was just a Dreyfus-style critic of AI, his ideas might not have gained much currency. However, to demonstrate the validity of his claims, he has built a number of robots, based on the subsumption architecture. A subsumption architecture is a hierarchy of task-accomplishing behaviours. Each behaviour 'competes' with the others to exercise control over the robot. Lower layers represent more primitive kinds of behaviour, (such as avoiding obstacles), and have precedence over layers further up the hierarchy. It should be stressed that the resulting systems are, in terms of the amount of computation they need to do, extremely simple, with no explicit reasoning, or even pattern matching, of the kind found in symbolic AI systems. But despite this simplicity, Brooks has demonstrated the robots doing tasks that would be impressive if they were accomplished by symbolic AI systems. Similar work has been reported by Steels, who described simulations of 'Mars explorer' systems, containing a large number of subsumption-architecture agents, that can achieve near-optimal performance in certain tasks  .