Copycat is a
model
A model is an informative representation of an object, person, or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin , .
Models can be divided in ...
of
analogy making and human
cognition
Cognition is the "mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
based on the concept of the
parallel terraced scan, developed in 1988 by
Douglas Hofstadter
Douglas Richard Hofstadter (born 15 February 1945) is an American cognitive and computer scientist whose research includes concepts such as the sense of self in relation to the external world, consciousness, analogy-making, Strange loop, strange ...
,
Melanie Mitchell, and others at th
Center for Research on Concepts and Cognition Indiana University Bloomington
Indiana University Bloomington (IU Bloomington, Indiana University, IU, IUB, or Indiana) is a public university, public research university in Bloomington, Indiana, United States. It is the flagship university, flagship campus of Indiana Univer ...
.
The original Copycat was written in
Common Lisp
Common Lisp (CL) is a dialect of the Lisp programming language, published in American National Standards Institute (ANSI) standard document ''ANSI INCITS 226-1994 (S2018)'' (formerly ''X3.226-1994 (R1999)''). The Common Lisp HyperSpec, a hyperli ...
and is
bitrotten (as it relies on now-outdated graphics libraries for Lucid Common Lisp); however, Java and Python ports exist. The latest versions are a 202
JavaScript portby Paul-G2 and a 201
Python3 portby Lucas Saldyt and J. Alan Brogan.
Description
Copycat produces answers to such problems as "abc is to abd as ijk is to what?" (abc:abd :: ijk:?). 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 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 (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to sensory memory, the initial stage, and short-term or working memory, the second stage ...
). 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 systems), and the ''coderack'' (with the codelets). The slipnet is a network composed of nodes, which represent permanent concepts, and weighted links, which are relations, between them. It differs from
traditional semantic networks, since the effective weight associated with a particular link may vary through time according to the activation level of specific concepts (nodes). The codelets build structures in the working area and modify activations in the slipnet accordingly (bottom-up processes), and the current state of slipnet determines probabilistically which codelets must be run (top-down influences).
Comparison to other cognitive architectures
Copycat differs considerably in many respects from other
cognitive architecture
A cognitive architecture is both a theory about the structure of the human mind and to a computational instantiation of such a theory used in the fields of artificial intelligence (AI) and computational cognitive science. These formalized models ...
s such as
ACT-R
ACT-R (pronounced /ˌækt ˈɑr/; short for "Adaptive Control of Thought—Rational") is a cognitive architecture mainly developed by John Robert Anderson and Christian Lebiere at Carnegie Mellon University. Like any cognitive architecture, ACT ...
,
Soar,
DUAL,
Psi-Theory
Psi-theory, developed by Dietrich Dörner at the University of Bamberg, is a systemic psychological theory covering human action regulation, intention selection and emotion.Dörner, D., Bartl, C., Detje, F., Gerdes, J., Halcour, D., Schaub, H., S ...
, or
subsumption architecture
Subsumption architecture is a reactive robotic architecture heavily associated with behavior-based robotics which was very popular in the 1980s and 90s. The term was introduced by Rodney Brooks and colleagues in 1986.Brooks, R. A., "A Robust Pro ...
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.
See also
*
Artificial consciousness
*
LIDA (cognitive architecture)
The LIDA (Learning Intelligent Decision Agent) cognitive architecture, previously Learning Intelligent Distribution Agent for its origins in IDA, attempts to model a broad spectrum of cognition in biological systems, from low-level perception/acti ...
References
Further reading
* (1993)
*
External links
A short description of CopycatGithub repository of copycat implementation (and other FARG projects)The Copycat Project: A Model of Mental Fluidity and Analogy-Making(pdf)
A Python version of Copycat by J. Alan Brogan, 2012A Python version of Copycat by Joseph Hager, 2017A JavaScript version of Copycatwit
an online demoby Paul-G2, 2023
* Abhijit Mahabal's Seqsee code i
Perland i
Python
*
ttp://ericpnichols.com/musicat/ Eric Nichols' Musicat dissertationThe Letter Spirit page at the Center for Research on Concepts and Cognition{{Douglas Hofstadter
Cognitive architecture
Common Lisp (programming language) software