Publicité
Publicité

Contenu connexe

Similaire à Towards which Intelligence? Cognition as Design Key for building Artificial Intelligent Systems(20)

Publicité
Publicité

Towards which Intelligence? Cognition as Design Key for building Artificial Intelligent Systems

  1. Towards which Intelligence? Cognition as Design Key for building Artificial Intelligent Systems Antonio Lieto University of Turin, Dipartimento di Informatica, Italy ICAR - CNR, Palermo, Italy Symposium “Bridging the Gap between Cognitive Psychology and Artificial Intelligence” ESCOP 2015, Paphos, Cyprus, 19th September 2015
  2. Outline • Which “Intelligence” in Artificial Intelligence (AI)? • Cognitive AI: methodological and technical considerations. • A case study (Time permitting !): System dealing with Common Sense Reasoning (Conceptual Categorization, paper presented at IJCAI 2015). 2
  3. Which“Intelligence” in AI? (partial overview) Early AI Cognitive Inspiration for the Design of “Intelligent Systems” M. Minsky R. Shank Modern AI “Intelligence” in terms of optimality of a performance (narrow tasks) J. McCarthy mid‘80s A. Newell H. Simon deep learning
  4. A focus shift in AI P. Langley (2012) “Vision the early days of AI: Understanding and reproducing, in computational systems, the full range of intelligent behavior observed in humans”. Why this view has been abandoned? - Emphasis on quantitative results and metrics of performance: (“machine intelligence”: achieving results and optimize them !) - Commercial success of narrow applications etc. Nowadays it is regaining attention since “The gap between natural and artificial systems is still enormous” (A. Sloman, AIC 2014) 4
  5. Cognitive AI Attention to the heuristics-based solutions adopted by humans (e.g. Gigerenzer & Todd, 1999) for combinatorial problems (“bounded rationality heuristics”). Heuristics realize/implement some cognitive functions and are responsible of the macroscopic external behaviour of an agent. 5
  6. 2 Perspectives The “Cognitive Systems” one (Brachman and Lemnios, 2002), referring to the discipline that: “designs, constructs, and studies computational artifacts that exhibit the full range of human intelligence”. The“nouvelle AI” (e.g. Parallel Distributed Processing (Rumhelarth and McLelland, 1986): based on bio- plausibility modelling techniques allowing the functional reproduction of heuristics in artificial systems (neglecting the physical and chemical details). 6
  7. Cognitive Systems Paradigm Langley (2012): • Focus on high level human cognitive functions • Assuming structured representations (physical symbol system, Simon and Newell, 1976) • Architectural Perspective (integration and interaction of all cognitive functions) • Inspiration from human cognition
  8. “Nouvelle” AI paradigm • Focus not only on high level cognitive functions (but also on perception, vision etc.) • Assuming unstructured representation (e.g. such as neural networks etc.) and also integration with symbolic approaches. • System perspective (not necessary to consider a whole architectural perspective). • Bio-inspired computing, bottom-up approach (for learning etc.). 8
  9. A Matter of Levels • Both the “classical” and “nouvelle” approach can realize, in principle, “cognitive artificial systems” or “artificial models of cognition” provided that their models operate at the “right” level of description. • A debated problem in AI and Cognitive Science regards the legitimate level of descriptions of such models (and therefore their explanatory power). Functionalist vs Structuralist Models 9
  10. Functionalism • Functionalism (introduced by Putnam) postulates a weak equivalence between cognitive processes and AI procedures. • AI procedures have the functional role (“function as”) human cognitive procedures. • Multiple realizability (functions can be implemented in different ways). • Equivalence on the functional macroscopic properties of a given intelligent behaviour (based on the same input-output specification). • This should produce predictive models (given an input and a set of procedures functionally equivalent to what is performed by cognitive processes then one can predict a given output). 10
  11. Problem with Functionalism • If the equivalence is so weak it is not possible to interpret the results of a system (e.g. interpretation of the system failures…) • A pure functionalist model (posed without structural constraints) is a black box where a predictive model with the same output of a cognitive process can be obtained with no explanatory power. • An analogy: A Bird and a Jet can fly but a jet is not a good explanatory model of a bird since its flights mechanisms are different from the mechanism of bird. • Purely functional models/systems (like IBM Watson) are not “computational models of cognition” 11
  12. Structuralism • Strong equivalence between cognitive processes and AI procedures (Milkowski, 2013). • Focus not only on the functional organization of the processes but also on the human-likeliness of a model (bio-psychological plausibility). • Wiener’s paradox: “The best material model of a cat is another or possibly the same cat” 12
  13. A Design Problem Pylyshyn (1979): “if we do not formulate any restriction about a model we obtain the functionalism of a Turing machine. If we apply all the possible restrictions we reproduce a whole human being” • Need for looking at a descriptive level on which to enforce the constraints in order to carry out a human like computation. • A design perspective: between the explanatory level of functionalism (based on the macroscopic stimulus-response relationship) and the mycroscopic one of fully structured models (reductionist materialism) we have, in the middle, a lot of possible structural models. 13
  14. “Cognition” as Design Constraint • We need a function-structure coupling for the design of cognitive artificial system. • The interpretations of the experimental results coming from cognitive psychology indicate us the algorithm procedures (the heuristics/design constraints) that we can implement in our system in a functional-structural way. • I.e. the implementation can be done in different ways (multiple realizability account of the functionalism) but the model needs to be constrained to the target system (needs to be structurally valid). 14
  15. Case Study A Common Sense Reasoning System IJCAI’15 Paper Antonio Lieto, Daniele P. Radicioni and Valentina Rho, “A Common-Sense Conceptual Categorization System Integrating Heterogeneous Proxytypes and the Dual Process of Reasoning”. In Proceedings of the International Joint Conference on Artificial Intelligence (IJCAI), Buenos Aires, July 2015, pp. 875-881. AAAI press. 15
  16. System Assumptions – Representation: – conceptual structures as heterogeneous proxytypes (Lieto 2014); compliance with the computational frameworks of cognitive architectures (General Architectures for Intelligence). – Reasoning: – 2 types of common sense inference (based on prototypes and exemplars). – Dual process reasoning (Common sense + Standard categorization). – Integration into the ACT-R cognitive architecture (Anderson et al. 2004).
  17. Prototypes and Prototypical Reasoning • Categories based on prototypes (Rosh, 1975) • New items are compared to the prototype atypical typical P
  18. Exemplars and Exemplar-based Reasoning • Categories as composed by a list of exemplars. New percepts are compared to known exemplars (not to Prototypes).
  19. Heterogeneous Hypothesis The different proposals that have been advanced can be grouped in three main classes: a) fuzzy approaches, b) probabilistic and Bayesan approaches, c) approaches based on non-monotonic formalisms. Different representational structures have different accessing procedures (reasoning) to their content. Prototypes, Exemplars and other conceptual representations can co-exists and be activated in different contexts (Malt 1989).
  20. System Conceptual Structure 20 differ- spec- terms illian, es can egion spec- an, on f con- ilarly, mbolic ell as an be tems, artic- so for iple–, is-a: feline color: yellow hasPart: fur hasPart: tail hasPart: stripes ... conceptual space representation concept Tiger Kingdom: Animalia Class: Mammalia Order: Carnivora Genus: Panthera Species: P. tigris prototype of Tiger exemplars of Tiger white-tiger is-a: feline color: white hasPart: fur hasPart: tail hasPart: stripes ... ... ontological representation classical information Typicality-based knowledge Classical knowledge Hybrid Knowledge Base
  21. Dual Process Reasoning 11 Reasoning Harmonization based on the dual process (Stanovitch and West, 2000; Kahnemann 2011). In human cognition, type 1 processes are executed fast and are not based on logical rules. Then they are checked against more logical deliberative processes (type 2 processes). Type 1 Processes Type 2 Processes Automatic Controllable Parallel, Fast Sequential, Slow Pragmatic/contextualized Logical/Abstract
  22. Overview NL Description -The big fish eating plankton Typical Representations IE step and mapping List of Concepts : -Whale 0.1 -Shark 0.5 -… Output S1 (Prototype or Exemplar) Check on S2 Ontological Repr. -Whale NOT Fish -Whale Shark OK Output S2 (CYC) Output S1 + S2 Whale Whale Shark
  23. Cognitive Architectures 23 Allen Newell (1990) Unified Theory of Cognition A cognitive architecture (Newell, 1990) implements the invariant structure of the cognitive system. It captures the underlying commonality between different intelligent agents and provides a framework from which intelligent behavior arises. The architectural approach emphasizes the role of memory in the cognitive process.
  24. Heterogeneous Proxytypes The different proposals that have been advanced can be grouped in three main classes: a) fuzzy approaches, b) probabilistic and Bayesan approaches, c) approaches based on non-monotonic formalisms. Concepts as Heterogeneous Proxytypes (Lieto, 2014). Stored in our long term memory and, activate in our working memory only specific representations (“go proxy”).
  25. Evaluation (Human-Machine Comparison) • 122 textual stimuli created by a team of neuropsychologists and tested in categorisation task during neuromaging experiments (FMRI). • 40 human subjects were requested to categorize such stimuli (and to specify the corresponding representation activated). • The provided answers are a Gold Standard and represents the expected results. • 84% of system answers overlapping with human responses. The computational experimentation also provided insights for the refinement of the theory (details in the paper!)
  26. Take home message • After two decades, Cognitive AI field is gaining a renewed attention. • Cognitive Artificial Models of AI are proxyies of a target system and have an explanatory power only if they are structurally valid models (realizable in different ways). • Cognitive Artificial Systems built with this design perspective can have an explanatory role for the theory they implement and the “computational experiment” can provide results useful for refining of retaining theoretical aspects.
  27. Join us at AIC 2015 in Turin ! 28-29 Sept. 2015 27
  28. Thanks ! Contacts: lieto.antonio@gmail.com Symposium “Bridging the Gap between Cognitive Psychology and Artificial Intelligence” ESCOP 2015, Paphos, Cyprus, 19th September 2015
Publicité