Glossary and bibliography
Because I thought this theory of the mind might interest not only
specialists but everyone who thinks, I favored ordinary words over
the technical language of psychology. This was rarely any sacrifice
because so many psychological terms already stood for obsolete
ideas. But since I also wished to speak to specialists, I tried to
hide more technical ideas between the lines; I hope this second
level does not show. However there still were certain points at
which no ordinary words seemed satisfactory, and I had to invent new
terms or assign new meanings to old ones.
Accumulation
(12.6) A type of learning based on
collecting examples of an idea without attempting to describe
what they have in common. Contrast
with Uniframe.
Agency
(1.6) Any assembly of
parts considered in terms of what it can accomplish as a unit,
without regard to what each of its parts does by itself.
Agent
(1.4) Any
part or process of the mind that by itself is simple enough to
understand — even though the interactions among groups of
such agents may produce phenomena that are much harder to
understand.
Artificial Intelligence
(7.4) The field of research concerned
with making machines do things that people consider to require
intelligence. There is no clear boundary between psychology and
Artificial Intelligence because the brain itself is a kind of
machine. For an introduction to this field, I recommend Patrick
Winston's textbook Artificial Intelligence, Addison-Wesley,
1984. For more connections with psychology, see Roger Schank
and Kenneth Colby (eds.), Computer Models of Thought and
Language, Freeman, 1973. Some influential early ideas about
brains and machines can be seen in Warren McCulloch's
Embodiments of Mind, MIT Press, Cambridge, Mass.,
1966. See Intelligence.
Attachment Learning
(17.2) The specific theory, proposed
in this book, that the presence of someone to whom we are
emotionally attached has a special effect on how we learn,
especially in infancy. Attachment learning tends to cause us to
modify our goals — rather than merely improve our methods
for achieving the goals we already have.
B-Brain
(6.4)
Any part of the brain connected not to the outside world, but
only to another part of the same brain. Like a manager, a
B-brain can supervise an A-brain without understanding either
how the A-brain works or the problems with which the A-brain is
involved — for example, by recognizing patterns of
activity that indicate the A-brain is confused, wasting time in
repetitive activity, or focused on an unproductive level of
detail.
Block-Arch
(12.1) A
scenario adapted from Patrick Winston's doctoral
thesis, Learning Structural Descriptions by Examples,
in The Psychology of Computer Vision, P. H. Winston
(ed.), McGraw-Hill, 1975. The study of the world of
children's building-blocks may at first seem childishly
simple, but it has been one of the most productive areas of
research about Artificial Intelligence, child psychology, and
modern robotics engineering.
Censor
(27.2) An agent that
inhibits or suppresses the operation of other agents. Censorlike
agents are involved with how we learn from our mistakes. This
idea played a prominent role in Freud's theories but has
been virtually ignored by modern experimental psychologists
— presumably because it is hard to study what people do
not think. See Freud's 1905 book Jokes and Their Relation to
the Unconscious. I suspect censorlike agents may constitute the
larger part of human memory. The discussion of censors and jokes
in chapter 27 is based on my essay Jokes and Their Relation
to the Cognitive Unconscious, published in Cognitive
Constraints on Communication, Representations and Processes,
L. Vaina and J.K.K. Hintikka (eds.), . Reidel, 1981. See
Suppressors.
Challenger, Professor
(4.4) A rival of mine, disguised as the
treacherous archaeologist in Arthur Conan Doyle's novel The Lost
World, who resembles Sherlock Holmes's nemesis, the mathematician
Moriarty, except for being somewhat more honorable.
Closing the Ring
(19.10) A technique by which an agency can recall many
details of a memory from being given only a few cues.
Common Sense
(1.5) The mental skills that most people share.
Commonsense thinking is actually more complex than many of the
intellectual accomplishments that attract more attention and respect,
because the mental skills we call expertise often engage large
amounts of knowledge but usually employ only a few types of
representations. In contrast, common sense involves many different kinds
of representations and thus requires a larger range of different skills.
Computer Science
(6.8) A
science still in its infancy. While other sciences study how
particular types of objects interact, computer science studies
how interactions work in general — that is, how societies
of parts can accomplish what those parts cannot do
separately. Although computer science began with the study of
serial computers — that is, of machines that could do only
one thing at a time — it has grown to the point of
studying the sorts of interconnected networks of processes that
must go on inside societies of mind. (For an introduction to the
theory of single-process machines, see my book Computation:
Finite and Infinite Machines, Prentice-Hall, 1967.)
Consciousness
(6.1) In this
book, the word is used mainly for the myth that human minds
are self-aware in the sense of perceiving what happens
inside themselves. I maintain that human consciousness can never
represent what is occurring at the present moment, but only a
little of the recent past — partly because each agency has
a limited capacity to represent what happened recently and
partly because it takes time for agencies to communicate with
one another. Consciousness is peculiarly hard to describe
because each attempt to examine temporary memories distorts the
very records it is trying to inspect. The description of
consciousness in section 6.1 was
adapted from my epilogue to Vernor Vinge's novel True Names,
Bluejay Books, New York, 1984.
Context
(20.2) The effect upon one's state of mind of all the
influences present at the time. At each moment, the context within which
each agency works is determined by the activity of the nemes that reach
that agency. See Neme.
Cross-Exclusion
(16.4) An arrangement in which each of several agents is
connected so as to inhibit all the others — so that only one of
them can remain active at a time.
Cross-Realm Correspondence
(29.4) A structure that has useful
applications in two or more different mental realms. Such
correspondences sometimes enable us to transfer knowledge and skill from
one domain to another — without needing to accumulate experience
in that other realm. This is the basis of certain important kinds of
analogies and metaphors.
Creativity
(7.10) The myth that the production of novel ideas, artistic
or otherwise, comes from some distinctive form of thought. I recommend
the discussion of this subject in the chapter
Variations on a Theme as the Crux of Creativity, in Douglas
Hofstadter's Metamagical Themas, Basic Books, 1985.
Default Assumption
(8.5, 12.12)
The kind of assumption we make when we lack reasons to think
otherwise. For example, we assume by default that an
unfamiliar individual who belongs to a familiar class will think
and act like a typical member of that class. Default
assumptions are more than mere conveniences; they constitute our
most productive way to make generalizations. Although such
assumptions are frequently wrong, they usually do little harm
because they are automatically displaced when more specific
information becomes available. However, they can do incalculable
harm when they are held too rigidly.
Demon
(27.1) An agent that
constantly watches for a certain condition and intervenes when
it occurs. Our discussion of demons is partly based on Eugene
Charniak's doctoral thesis,
Toward a Model of Children's Story Comprehension,
MIT, 1972.
Difference-Engine
(7.8) An
agency whose actions tend to make the present state of affairs
more like some goal or desired state whose description
is represented in that agency. This idea was developed by Allen
Newell, C. J. Shaw, and Herbert A. Simon into an important
theory about human problem solving. See G. Ernst and Allen
Newell, GPS, A Case Study in Generality and Problem
Solving, Academic Press, 1969.
Direction-Neme
(24.6) An
agent associated with a particular direction or region in
space. I suspect that bundles of direction-nemes are used inside
our brains for representing not only spatial locations and
directions, but also for representing many nonspatial
concepts. Direction-nemes resemble isonomes in spatial realms
but more resemble polynemes in other realms.
See Interaction-Square and
Frame-Array.
Distributed Memory
(20.9) A
representation in which each fragment of information is stored,
not by making a single, substantial change in one agent, but by
making small changes in many different agents. Many theorists
have been led to believe that the construction of distributed
memory-systems must involve
nondigital devices such as holograms; that this is not so was
shown by P. J. Willshaw, 0. P. Buneman, and H. C. Longuet-Higgins
in Non-Holographic Associative Memory, Nature, 222, 1969. See
Memorizers.
Duplication Problem
(23.2)
The question of how a mind could compare two similar ideas
without possessing two identical agencies for representing both
of them at the same time. This problem was never recognized in
older theories of psychology, and I suspect it will be the
downfall of most holistic theories of higher-level
thought. See Time Blinking.
Emotion
(16.1) A term used
for too many different purposes. There is a popular view that
emotions are inherently more complex and harder to understand
than other aspects of human thought. I maintain that infantile
emotions are comparatively simple in character and that the
complexity of adult emotions results from accumulating networks
of mutual exploitations. In adults, these networks eventually
become indescribably complicated, but no more so than the
networks of our adult intellectual structures. Beyond
a certain point, to distinguish between the emotional and
intellectual structures of an adult is merely to describe the
same structures from different points of view. See
Proto-specialist.
Exploitation
(4.5) The act of one agency making use of the activity of
another agency, without understanding how it works. Exploitation is the
most usual relationship among agencies because it is so difficult for
them to understand one another.
Exception Principle
(12.9) The concept that it may not pay to change a
well-established skill in order to accommodate an exception. The more
one builds upon a certain foundation, the greater the disruption upon
changing it. A system's growth will tend to cease, past the point at
which the damage caused by any change outweighs the immediate gain. See
Investment Principle.
Frame
(24.2) A
representation based on a set of terminals to which other
structures can be attached. Normally, each terminal is connected
to a default assumption, which is easily displaced by more
specific information. Other ideas about frames that are not
discussed within this book were published in my chapter A
Framework for Representing Knowledge, in Psychology of
Computer Vision, P. H. Winston (ed.), McGraw-Hill,
1975. See Picture-Frames, Trans-frame.
Frame-Array
(25.2) A family
of frames that share the same terminals. Information attached
to any terminal of a frame-array automatically becomes available
to all the frames of that array. This makes it easy to change
perspective, not only in regard to a physical viewpoint, but in
other mental realms as well. Frame-arrays are often controlled
by bundles of direction-nemes.
Functional Autonomy
(17.4)
The idea that specific goals can lead to subgoals of broader
character. For example, in order to please another individual, a
child might develop more general goals of acquiring knowledge,
power, or wealth — yet the very same subgoals might serve
equally well an initial wish to injure that other
individual. The term functional autonomy derives from
Gordon Allport, who was one of my professors at Harvard.
Functional Definition
(12.4) Specifying something in terms
of how it might be used, rather than in terms of its parts and
their
relationships. See Structural
Definition.
Generate and Test
(7.3)
Solving a problem by trial and error — that is, by
proposing solutions recklessly, then rejecting those that do not
work.
Genius
(7.10) An individual of
prodigious mental accomplishment. Although even the most
outstanding human prodigies rarely develop even twice as quickly
as their peers, many people feel that their existence demands a
special explanation. I suspect that the answer is to be found
not in the superficial skills such people learn, but in the
early accidents that lead them into learning better ways to
learn.
Goal
(7.8) The representation in a difference-engine of an imagined
final state of affairs. This definition of goal may at first seem too
impersonal because it does not explain either the elation that comes
with achieving a human goal or the frustration that accompanies
failure. However, we should not expect to explain such complicated
phenomena of adult psychology directly in terms of simple principles,
since they also depend on many other aspects of our mental
architecture. Basing our concept of goal on the difference-engine idea
helps us to avoid the single-agent fallacy by permitting us to speak
about a goal without needing to refer to the person who entertains that
goal; a person's many agencies may each have different goals —
without that person being aware of them.
Grammar-Tactic
(22.10) An
operation involved with speech that corresponds to a step in a
process of constructing a mental representation. Grammar-tactics
are not the same as grammar rules, although these have
a close relation. The difference is that grammar rules are both
superficial and subjective — in the sense that they
purport to describe regularities in one person's behavior as
observed by someone else — while grammar-tactics are
objective in the sense that they are defined to be the
underlying processes that actually produce speech. Although it
may be more difficult to discover just what those processes do,
it is better to speculate on how language is produced and used
than merely to describe its observed, external forms.
Homunculus
(5.2) Literally, a tiny person. In psychology, the
unproductive and paradoxical idea that a person's behavior depends
upon the behavior of another personlike entity located deeper inside
that person.
Interaction-Square
(14.9) The idea of representing the
interaction between two processes by linking pairs of examples
to direction-nemes. We can use this same technique not only for
representing spatial relationships, but for causal, temporal,
and many other kinds of interactions. This makes the
interaction-square idea a powerful scheme for representing
cross-realm correspondences.
Interaction
(2.1) The effect
of one part of a system upon another part. It is remarkable
that in the history of science virtually all phenomena have
eventually been explained in terms of interactions between parts
taken two at a time. For example, Newton's law of gravity,
which describes the mutual attraction of two particles, enables
us to predict the motions of all the planets, stars, and
galaxies — without any need to consider three or more
objects at a time! One could conceive of a universe in which
whenever three stars formed an equilateral triangle, one of them
would instantly disappear — but virtually no three-part
interactions have ever been observed in the physical world.
Interruption
(15.9) A term
used in this book to refer to any process that can be suspended
while the agency involved can do some other job — yet
later return to where it left off. The ability to do this
requires some sort of temporary
memory. See Recursion
Principle.
Intelligence
(7.1) A term frequently
used to express the myth that some single entity or element is
responsible for the quality of a person's ability to
reason. I prefer to think of this word as representing not any
particular power or phenomenon, but simply all the mental skills
that, at any particular moment, we admire but don't yet
understand.
Introspection
(6.5) The myth
that our minds possess the ability directly to perceive or
apprehend their own operations.
Intuition
(12.10) The myth that the mind possesses some immediate (and
hence inexplicable) abilities to solve problems or perceive truths. This
belief is based on naive views of how we get ideas. For example, we
often experience a moment of excitement or exhilaration at the moment of
completing a complex and pro longed but nonconscious analysis of a
problem. The myth of intuition wrongly attributes the solution to what
happened in that final moment. As for being able directly to apprehend
what is true, we simply forget how frequently our intuitions
turn out wrong.
Investment Principle
(14.6)
The tendency of any well-developed skill to retard the growth of
similar skills because the latter work less well in their early
forms — and hence are used so infrequently that they never
reach maturity. Because of this, we tend to invest most of our
time and effort on elaborating a comparatively few techniques,
rather than on accumulating many different ones. This can lead,
at the same time, both to the formation of a coherent and
effective personal style and to a decline in flexibility that
may be wrongly attributed to
aging. See Exception
Principle.
Isonome
(22.1) A signal or
pathway in the brain that has similar effects on several
different agencies.
K-Line
(8.1) The theory that
certain kinds of memories are based on turning on sets of agents
that reactivate one's previous partial mental states. This
idea was first described in my essay K-lines: A Theory of
Memory, Cognitive Science, 4 (2), April 1980.
Learning
(7.5) An omnibus
word for all the processes that lead to long-term changes in our
minds.
Level-Band
(8.5) The idea that a typical mental process tends to
operate, at each moment, only within a certain range or portion of the
structure of each agency. This makes it possible for one process to work
on small details without disrupting other processes that are concerned
with large-scale plans.
Logical Thinking
(18.1) The
popular but unsound theory that much of human reasoning proceeds
in accord with clear-cut rules that lead to foolproof
conclusions. In my view, we employ logical reasoning only in
special forms of adult thought, which are used mainly to
summarize what has already been discovered. Most of our ordinary
mental work — that is, our commonsense reasoning —
is based more on thinking by analogy — that is,
applying to our present circumstances our representations of
seemingly similar previous experiences.
Memorizer
(19.5) An agent
that can reset an agency into some previously useful state. See
Recognizer
and Distributed Memory.
Memory
(15.3) An omnibus
term for a great many structures and processes that have
ill-defined boundaries in both everyday and technical
psychology; these include what we call
re-membering, re-collecting, re-minding, and
recognizing. This book suggests that what these share in common
is their involvement with how we reproduce our former partial mental
states.
Mental State
(8.4) The
condition of activity of a group of agents at a certain
moment. In this book we have assumed that every agent, at any
moment, is either completely aroused or completely quiescent; in
other words, we ignore the possibility of different degrees of
arousal. This kind of two-state or digital
assumption is characteristic of computer science and, at first,
may seem too simplistic. However, experience has shown that the
so-called analog theories that are alleged to be more realistic
quickly become so complicated that, in the end, the simpler
two-state models actually lead to deeper understandings —
at least about basic
principles. See Partial Mental
State.
Metaphor
(29.8) The myth
that there is a clear distinction between representations that
are realistic and those that are merely suggestive. In
their book Metaphors We Live By, University of Chicago Press,
1980, Mark Johnson and George Lakoff demonstrate that metaphor
is no mere special device of literary expression but permeates
virtually every aspect of human thought.
Micromemory
(15.8) The
smallest components of our short-term memory-systems.
Microneme
(20.5) A neme
involved with agents at a relatively low
level. See Neme.
Model
(30.3) Any structure
that a person can use to simulate or anticipate the behavior of
something else.
Neme
(25.6) An
agent whose output represents a fragment of an idea or state of
mind. The context within which a typical agent works is
largely determined by the activity of the nemes that reach it. I
called nemes C-lines in Plain Talk About Neuro-
developmental Epistemology, in Proceedings of the Fifth
International Joint Conference on Artificial Intelligence,
Cambridge, Mass., 1977; the description in section 20. 5 is also
based on the idea of microfeature developed by David
L.Waltz and Jordan Pollack in Massively Parallel
Parsing, Cognitive Science, 9 (1).
Nome
(25.6) An
agent whose outputs affect an agency in some predetermined
manner, such as a pronome, isonome, or paranome; an agent whose
effect depends more on genetic architecture than on learning
from experience. The suffix -nome was chosen to suggest an
atom-like, unchanging quality.
Noncompromise Principle
(3.2) The idea that when two agencies
conflict it may be better to ignore them both and yield control
to yet another, independent agency.
Papert's Principle
(10.4) The hypothesis that many
steps in mental growth are based less on the acquisition of new
skills than on building new administrative systems for managing
already established abilities.
Paranome
(29.3) An agent that operates on
agencies of several different mental realms at once, with
similar effects on all of them.
Partial Mental State
(8.4) A description of the state of
activity of some particular group of mental agents. This
technical but simple idea makes it easy to understand how one
can entertain and combine several ideas at the same time. See
Mental State.
Perceptron
(19.7) A type of recognition machine
that learns to weigh evidence. Invented by Frank Rosenblatt in
the late 1950s, Perceptrons use singularly simple procedures for
learning which weights to assign to various fragments of
evidence. Seymour Papert and I analyzed this type of machine in
the book Perceptrons, MIT Press, 1969, and showed that
the simplest kinds of Perceptrons cannot do very much by
themselves. However, they can do much more when arranged into
societies so that some of them can then learn to recognize
relations among the patterns recognized by the others. It seems
quite likely that some types of brain cells use similar
principles.
Picture-Frames
(24.7) A type of frame whose
terminals are controlled by direction-nemes. Picture-frames are
particularly suited to representing certain kinds of spatial
information.
Polyneme
(19.5) An agent that arouses
different activities, at the same time, in different agencies
— as a result of learning from experience. Contrast with
Isonome.
Pronome
(21.1 ) A type of agent associated with a
particular role or aspect of a representation —
corresponding, for example, to the Actor, Trajectory, or Cause of some
action. Pronome agents frequently control the attachments of terminals
of frames to other frames; to do this, a pronome must possess some
temporary memory.
Proto-specialist
(16.3) One of the genetically
constructed subsystems responsible for some of an
animal's instinctive behavior. Large portions of
our minds start out as almost separate proto-specialists, and we
interpret their activity as manifesting different, primitive
emotions. Later, as agencies become more interconnected and
learn to exploit one another, these differences grow less
distinct. This conception is based on the societylike theory
proposed by Niko Tinbergen in The Study of Instinct, Oxford
University Press, 1951.
Puzzle Principle
(7.3) The idea that any problem can
be solved by trial and error — provided one already has
some way to recognize a solution when one is
found. See Generate and
Test.
Realm, Mental
(29.1) A division of the mind that
deals with some distinct variety of concern by using distinct
mechanisms and representations.
Recognizer
(19.6) An agent that becomes active
in response to a particular pattern of input signals.
Recursion Principle
( 15.11 ) The idea that no society,
however large, can overcome every limitation — unless it
has some way to reuse the same agents, over and over again, for
different purposes. See Interruption.
Reformulation
(13.1) Replacing one representation
of something by another, different type of representation.
Representation
(21.6) A structure that can be used
as a substitute for something else, for a certain purpose, as
one can use a map as a substitute for an actual city. See
Functional Definition and
Model.
Re-duplication Theory of Speech
(22.10) My conjecture about what
happens when a speaker explains an idea to a listener. A
difference-enginelike process tries to construct a second copy
of the idea's representation inside the speaker's
mind. Each mental operation used in the course of that
duplication process activates a corresponding grammar-tactic in
the language- agency, and these lead to a stream of speech. This
will result in communication to the extent that suitably matched
inverse grammar-tactics construct, inside the listener's
mind, an equivalent representation.
Script
(13.5)
A sequence of actions produced so automatically that it can be
performed without disturbing the activities of many other
agencies. The action script in
section 21.7 accomplishes this by
eliminating all the higher-level managers like Put and Get. A
script-based skill tends to be inflexible because it lacks
bureaucracy; one gains speed by removing higher-level anchor
points but loses access to alternatives when things go wrong;
script-based experts run the risk of becoming inarticulate. The
book by Roger Schank and Robert Abelson, Scripts, Goals, Plans
and Understanding, Erlbaum Associates, 1977, speculates about
the human use of scripts.
Self
(4.1) In
this book, when written Self, the myth that each of us
contains some special part that embodies the essence of the
mind. When written as self, the word has the ordinary
sense of a person's individuality. See Single-Agent
Fallacy.
Single-Agent Fallacy
(4.1) The idea that a person's
thought, will, decisions, and actions originate in some single
center of control, instead of emerging from the activity of
complex societies of processes.
Simulation
(2.4) A situation in which one system
mimics the behavior of another. In principle, a modern computer
can be used to simulate any other kind of machine. This is
important for psychology, because in the past, there was usually
no way for scientists to confirm their expectations about the
consequences of a complicated theory or mechanism. The theories
in this book have not yet been simulated, partly because they
are not specified clearly enough and partly because the older
computers lacked enough capacity and speed to simulate enough
agents. Such machines have recently become available; for an
example, see W. Daniel Hillis's doctoral thesis, The
Connection Machine, MIT Press, Cambridge, Mass., 1985.
Simulus
(16.8) An illusion that a certain
thing is present, caused by a process that evokes, at higher
levels of the mind, a state resembling the state of mind that
would be caused by that thing's actual presence. (A new
word. )
Society
(1.1)
In this book, an organization of parts of a mind. I reserved the
term community for referring to organizations of people
because I did not want to suggest that a human mind resembles a
human community in any particular way.
Society of More
(10.2) The agents used by a mind to
make comparisons of quantities.
Stage of Development
(16.2) An episode in the growth of a
mind. Chapter 17 offers several
reasons why complicated systems tend to grow in sequences of
episodes, rather than through processes of steady change.
State of Mind
(8.4)
See Mental State.
Structural Definition
(12.4) Describing something in terms
of the relationships among its parts. Contrast
with Functional Definition.
Suppressor
(27.2) A censorlike agent that works
by disrupting a mental state that has already
occurred. Suppressors are easier to construct than censors, and
require less memory, but are much less efficient.
Time Blinking
(23.3) Finding differences between
two mental states by activating them in rapid succession and
noticing which agents change their states. I suspect it is by
using this method that our brains avoid the duplication problem
mentioned in section 23.2. Time
blinking might be one of the synchronized activities of brain
cells that gives rise to brain waves.
Trajectory
(21.6) Literally, the path or route
of an action or activity. However, we use this word not only
for a path in space, but, by analogy, for other realms of
thought. See Pronome.
Trans-Frame
(21.3) A particular type of frame
that is centered around the trajectory between two situations,
one for before and the other for after. The
theories in this book about Trans-frames owe much to Roger
Schank. See his book, Conceptual Information Processing,
North-Holland, 1975.
Unconscious
(17.10) A term often used, in
common-sense psychology, to refer to areas of thought that are
actively barred or censored against introspection. In this book
we take conscious to mean aspects of our mental
activity of which we are aware. But since there are very few
such processes, we must consider virtually everything done by
the mind to be unconscious.
Uniframe
(12.3) A description designed to
represent whichever common aspects of a group of things can be
used to distinguish them from other things.
Will, Freedom of
(30.6) The myth that human volition
is based upon some third alternative to either causality or
chance.