Allen Newell December 4, 1991 Great Questions of Science You need to realize if you haven t before that there is this collection of ultimate scientific questions and if you are lucky to get grabbed by one of these that will just do you for the rest of your life. Why does the universe exist? When did it start? What s the nature of life? All of these are questions of a depth about the nature of our universe that they can hold you for an entire life and you are just a little ways into them.
Allen Newell December 4, 1991 Cognitive Science has a Great Question! The question for me is how can the human mind occur in the physical universe. We now know that the world is governed by physics. We now understand the way biology nestles comfortably within that. The issue is how will the mind do that as well. The answer must have the details. I got to know how the gears clank and how the pistons go and all the rest of that detail. My question leads me down to worry about the architecture.
Some Famous Cognitive Architectures (according to Wikipedia) ACT-R Apex CHREST CLARION Copycat DUAL EPIC H-Cogaff IDA and LIDA PRODIGY PRS Psi-Theory R-CAST Soar Society of mind Subsumption architectures
Wikipedia: Cognitive architectures can be symbolic, connectionist, or hybrid. Google Hits: Symbolic Architecture : 15,100 Connectionist Architecture :16,300 Hybrid Architecture : 73,400 Cognitive Architecture : 98,900
Wikipedia: Architecture: Relating Structure to Function? According to the very earliest surviving work on the subject, Vitruvius 'De Architectura, good buildings should have Beauty (Venustas), Firmness (Firmitas) and Utility (Utilitas); architecture can be said to be a balance and coordination among these three elements, with none overpowering the others. A modern day definition sees architecture as addressing aesthetic, structural and functional considerations.
Computer Architecture: Relating Structure to Function Frederick Brooks Planning a Computer System (1962): Computer architecture, like other architecture, is the art of determining the needs of the user of a structure and then designing to meet those needs as effectively as possible within economic and technological constraints. Architecture must include engineering considerations, so that the design will be economical and feasible; but the emphasis in architecture is on the needs of the user, whereas in engineering the emphasis is on the needs of the fabricator.
Bell & Newell: Computer Structures (1970) Newell: I took one thing out of this 7 years experience -- namely, I understood what architectures were about
Cognitive Architecture: The Key Abstraction between Brain and Mind Newell (1990): Our ultimate goal is unified theory of human cognition. This will be expressed as a theory of the architecture of human cognition -- that is, of the fixed structure that forms the framework for the immediate processes of cognitive performance and learning. Pylyshyn (1984): The functional architecture includes the basic operations provided by the biological substrate, say, for storing and retrieving symbols, comparing them, treating them differently as a function of how they are stored. Anderson (1983) : ACT* is a theory of cognitive architecture -- that is a theory of the basic principles of operation built into the cognitive system. Anderson (2007): A cognitive architecture is a specification of the structure of the brain at a level of abstraction that explains how it achieves the function of the mind.
Measures of Modern Cognitive Architectures Empirical Validity: Does the architecture capture the details of human performance in a wide range of cognitive tasks? Functionality: Does the architecture explain how humans achieve their high level of intellectual function? Biological plausibility: Does the architecture correspond to what we know about the brain?
ACT-R: Empirical Validity Modules are high capacity, parallel, and asynchronous Imaginal Buffers provide narrow paths of communication -- only hold a chunk in ACT-R terms. Visual Goal Procedural Key Learning and Subsymbolic Processes Retrieval Aural Production system that contains rules that recognize patterns and react Manual Vocal
Dario Salvucci: Driving a car Eye Movements
Driving while Dialing a Cell Phone
Soar: Functionality Intelligent core: Rete pattern matcher enables efficient detection of of relational patterns in LARGE working memory. While essential, an important question is what the exact bounds are on this capability.
TacAir Soar (1997) Controls simulated aircraft in real-time training exercises (>3000 entities) Flies all U.S. air missions Dynamically changes missions as appropriate Communicates and coordinates with computer and human controlled planes >8000 rules
Leabra: Biological (active maintenance) Frontal Cortex Gating for Motor Actions and WM Maintenance Plausibility Overlap for Generalization Takes Inputs from Everywhere and Decides what Representations to Emphasize Basal Ganglia (action selection) Pattern Separation and Past Learning for Episodic Memories. Posterior Cortex (sensory representations) Hippocampus (episodic memory)
Leabra Vision Model Invariant object recognition through learned incremental transformations (V1, V2, V4, IT: Deep network) High 90 s generalization to novel images/objects of trained categories (vehicles, faces, digits, etc) Key differences from std AI: bidirectional connectivity for top-down attn, attractors full n-way categorization (vs. sequential binary SVM) learns all levels of features (vs. hand-coded w/ learning only in final classifier)
Herb Simon on Brand Names We typically (and properly) implement our research with large complex systems that employ a collection of interacting mechanisms to achieve their results. Hence, we often think of advances in terms of the names of such programs: e.g., LT, GPS, EPAM, PRODIGY, Soar, BACON, ACT-R --just to mention a few of local origin. However, it can be argued that the real "action" lies largely in the mechanisms embedded in these programs, and in issues about how such mechanisms can be combined effectively. The "brand names" tend to make difficult the analysis and comparison of these mechanisms or the exchange of knowledge between research groups. One can argue that it has caused and causes an enormous amount of duplication of effort. Physicists did not divide quantum mechanics into the Heisenberg Brand, the Schrodinger Brand, and the Dirac brand.
Posterior Frontal Cortex Motor Cortex (active maintenance) Manual Frontal Cortex Goal Prefrontal Cortex Prefrontal Cortex Vocal Imagin al Aural Procedural Basal Ganglia (action selection) Declar ative Memor y Posterior Cortex Posterior Cortex (sensory representations) Vision Where Vision What Hippocampus & Medial Temporal Cortex Hippocampus (episodic memory)
SAL = Synthesis of ACT-R and Leabra Vocal Manual Goal Imaginal Aural Procedural Declarative Memory Vision Where Vision What
Attentional Blink Taatgen et al.
The Three Questions 1. What was your area like at the time of the 1978 conference? While there were a number of aspiring efforts, there were no architectures that spanned human cognition. 2. How has the area changed over the past 30 years to what it is today? There are now a number of such architectures. 3. How do you foresee the area changing in the next 30 years? In keeping with their stated goal of unification, we should see a deeper understanding of the relationship among architectures and a merging of their strongest features.