Copycat (software)
Encyclopedia
Copycat is a model
of analogy making
and human cognition
based on the concept of the parallel terraced scan
, developed in 1988 by Douglas Hofstadter
, Melanie Mitchell
, and others at the at Center for Research on Concepts and Cognition, Indiana University Bloomington
. The original Copycat was written in Common Lisp
and is bitrotten (as it relies on now-outdated graphics libraries); however, a Java port exists.
High-level perception emerges
from the spreading activity of many independent processes, called codelets, running in parallel, competing or cooperating. They create and destroy temporary perceptual constructs, probabilistically trying out variations to eventually produce an answer. The codelets rely on an associative network, slipnet, built on pre-programmed concepts and their associations (a long-term memory
). The changing activation levels of the concepts make a conceptual overlap with neighboring concepts.
Copycat's architecture is tripartite, consisting of a slipnet, a working area (also called workspace
, similar to blackboard system
s), and the coderack (with the codelets). The slipnet is a network composed of nodes, which represent permanent concepts, and links, which are relations, between them. The codelets can modify activations in the slipnet, and build structures in the working area, based on the current state of the workspace and slipnet.
s such as ACT-R
, Soar
, DUAL, Psi, or subsumption architecture
s.
Copycat is Hofstadter's most popular model. Other models presented by Hofstadter et al. are similar in architecture, but different in the so-called microdomain, their application, e.g. Letter Spirit, etc.
Since the 1995 book Fluid Concepts and Creative Analogies describing the work of the Fluid Analogies Research Group (FARG) book, work on Copycat-like models has continued: as of 2008 the latest models are Phaeaco (a Bongard problem
solver), SeqSee (number sequence extrapolation), George (geometric exploration), and Musicat (a melodic expectation model). The architecture is known as the "FARGitecture" and current implementations use a variety of modern languages including C# and Java. A future FARG goal is to build a single generic FARGitecture software framework to facilitate experimentation.
Cognitive model
A cognitive model is an approximation to animal cognitive processes for the purposes of comprehension and prediction. Cognitive models can be developed within or without a cognitive architecture, though the two are not always easily distinguishable.In contrast to cognitive architectures, cognitive...
of analogy making
Analogy
Analogy is a cognitive process of transferring information or meaning from a particular subject to another particular subject , and a linguistic expression corresponding to such a process...
and human cognition
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...
based on the concept of the parallel terraced scan
Parallel terraced scan
The parallel terraced scan is a multi-agent based search technique that is basic to cognitive architectures, such as Copycat, Letter-string, the Examiner, Tabletop, and others...
, developed in 1988 by Douglas Hofstadter
Douglas Hofstadter
Douglas Richard Hofstadter is an American academic whose research focuses on consciousness, analogy-making, artistic creation, literary translation, and discovery in mathematics and physics...
, Melanie Mitchell
Melanie Mitchell
Melanie Mitchell is a professor of computer science at Portland State University. She has worked at the Santa Fe Institute and Los Alamos National Laboratory...
, and others at the at Center for Research on Concepts and Cognition, Indiana University Bloomington
Indiana University Bloomington
Indiana University Bloomington is a public research university located in Bloomington, Indiana, in the United States. IU Bloomington is the flagship campus of the Indiana University system. Being the flagship campus, IU Bloomington is often referred to simply as IU or Indiana...
. The original Copycat was written in Common Lisp
Common Lisp
Common Lisp, commonly abbreviated CL, is a dialect of the Lisp programming language, published in ANSI standard document ANSI INCITS 226-1994 , . From the ANSI Common Lisp standard the Common Lisp HyperSpec has been derived for use with web browsers...
and is bitrotten (as it relies on now-outdated graphics libraries); however, a Java port exists.
Description
Copycat produces answers to such problems as "abc is to abd as xyz is to what?" (abc:abd :: xyz:?). Hofstadter and Mitchell consider analogy making as the core of high-level cognition, or high-level perception, as Hofstadter calls it, basic to recognition and categorization.High-level perception emerges
Emergence
In philosophy, systems theory, science, and art, emergence is the way complex systems and patterns arise out of a multiplicity of relatively simple interactions. Emergence is central to the theories of integrative levels and of complex systems....
from the spreading activity of many independent processes, called codelets, running in parallel, competing or cooperating. They create and destroy temporary perceptual constructs, probabilistically trying out variations to eventually produce an answer. The codelets rely on an associative network, slipnet, built on pre-programmed concepts and their associations (a long-term memory
Long-term memory
Long-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. According to the theory, long term memory differs structurally and functionally from working memory or short-term memory, which ostensibly stores items for only around 20–30...
). The changing activation levels of the concepts make a conceptual overlap with neighboring concepts.
Copycat's architecture is tripartite, consisting of a slipnet, a working area (also called workspace
Workspace
Workspace is a term used in various branches of engineering and economic development.-Business development:Workspace refers to small premises provided, often by local authorities or economic development agencies, to help new businesses to establish themselves...
, similar to blackboard system
Blackboard system
A blackboard system is an artificial intelligence application based on the blackboard architectural model, where a common knowledge base, the "blackboard", is iteratively updated by a diverse group of specialist knowledge sources, starting with a problem specification and ending with a solution...
s), and the coderack (with the codelets). The slipnet is a network composed of nodes, which represent permanent concepts, and links, which are relations, between them. The codelets can modify activations in the slipnet, and build structures in the working area, based on the current state of the workspace and slipnet.
Comparison to other cognitive architectures
Copycat differs considerably in many respects from other cognitive architectureCognitive architecture
A cognitive architecture is a blueprint for intelligent agents. It proposes computational processes that act like certain cognitive systems, most often, like a person, or acts intelligent under some definition. Cognitive architectures form a subset of general agent architectures...
s such as ACT-R
ACT-R
ACT-R is a cognitive architecture mainly developed by John Robert Anderson at Carnegie Mellon University. Like any cognitive architecture, ACT-R aims to define the basic and irreducible cognitive and perceptual operations that enable the human mind....
, Soar
Soar (cognitive architecture)
Soar is a symbolic cognitive architecture, created by John Laird, Allen Newell, and Paul Rosenbloom at Carnegie Mellon University, now maintained by John Laird's research group at the University of Michigan. It is both a view of what cognition is and an implementation of that view through a...
, DUAL, Psi, or subsumption architecture
Subsumption architecture
Subsumption architecture is a reactive robot architecture heavily associated with behavior-based robotics. The term was introduced by Rodney Brooks and colleagues in 1986...
s.
Copycat is Hofstadter's most popular model. Other models presented by Hofstadter et al. are similar in architecture, but different in the so-called microdomain, their application, e.g. Letter Spirit, etc.
Since the 1995 book Fluid Concepts and Creative Analogies describing the work of the Fluid Analogies Research Group (FARG) book, work on Copycat-like models has continued: as of 2008 the latest models are Phaeaco (a Bongard problem
Bongard problem
A Bongard problem is a kind of puzzle invented by the Russian computer scientist Mikhail Moiseevich Bongard , probably in the mid-1960s. They were published in his eponymous 1967 book on pattern recognition...
solver), SeqSee (number sequence extrapolation), George (geometric exploration), and Musicat (a melodic expectation model). The architecture is known as the "FARGitecture" and current implementations use a variety of modern languages including C# and Java. A future FARG goal is to build a single generic FARGitecture software framework to facilitate experimentation.