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This paper is called
"Consciousness Redux" and is something of a history of theoretical
positions on the function of consciousness. It was written by
George Mandler of the University of California & University
College London.
Consciousness Redux
George Mandler
University of California, San
Diego and University College London
Copyright (C) 1993 George Mandler
I start with a review of 20 years of proposals on the functions of
consciousness. I then present a minimal number of functions that
consciouness subserves, as well as as some remaining puzzles about
its psychology. In the process I stress a psychologist's
functional approach, asking what consciousness is for. The result
is an attempt to place conscious processes within the usual flow of
human information processing.
Twenty years of - progress?
Twenty years ago I was writing a paper for a conference on
information processing and cognition organized by Robert Solso at
Loyola University in Chicago. The paper asserted in its title that
consciousness was respectable, useful, and probably necessary.[1]
As late as 1975 the topic and the assertion of consciousness'
respectability, utility, and necessity were still beyond the pale
for many of my peers.[2] Like other taboo topics recently
rehabilitated, the mention of consciousness still occasioned
embarrassed looking-at-the-ceiling and examining-of-cuticles, or
--- from the bolder ones --- sage advice that I was
foolish/misguided/downright-wrong to approach such a can of worms.
Ulric Neisser had tried to come to terms with consciousness in 1963
in the psychoanalytic context, but tended to avoid it in his 1967
book that defined parts of the new cognitive psychology. By 1970
consciousness started to become respectable and useful in human
information processing systems, in order to accommodate serial
processing (Atkinson & Shiffrin, 1968), to account for
attention in choice and rehearsal (Posner & Keele, 1970; Posner
& Boies, 1971), and to select and set goals for action systems
(Shallice, 1972).
Since then the proliferation of interest in consciousness has been
truly awesome. Philosophers --- as usual on the hunt for a juicy
topic --- joined the fray, and as of 1993 no respectable cognitive
scientist can be without a position on consciousness. An informal
recent survey suggests that for the N (a large number) proponents
of theoretical positions on consciousness, there are now N+1 (a
larger number) of theoretical positions. And there is little sign
of any centripetal tendency to find a core agreement among those
N+1 positions. As a result, I shall first describe briefly my own
development from the early speculations to a more recent position
(Mandler 1975a, 1984a, 1984b, 1985, 1986, 1988, 1989, 1992, 1993),
[3] followed by a discussion of several central notions: conscious
construction, the feedback function of consciousness, and the
seriality and limited capacity of consciousness. I will then
attempt to spell out some minimal requirements for a conscious
mechanisms together with a sampling of several puzzles of
consciousness that need more work. Finally I shall return to the
big picture, offer some speculations about the uses of "mind" and
end with a defense of a functionalist psychological approach.
Functions of consciousness: Constructions and
their consequences
My first substantial paper on consciousness started with some
musings about the possible functions of consciousness, which led
to:
Five functions in search of a mechanism
I started with a psychologist's functional approach, i.e., by
considering the functions and roles that consciousness apparently
fills in mental life, and to proceed then to imagine what such a
mechanisms would have to be like in order to accomplish all these
functions.[4] All my relevant efforts have appealed to
consciousness in terms of immediate experience, whether of extra-
or intra-psychic events or reflective. The question then is why
some mental contents appear in that conscious guise. I am concerned
with certain functions of human cognition that map on to
consciousness --- when mental contents are in the conscious state
they tend to display such functions as seriality and limited
capacity and are likely to prime underlying representations.
In the 1975a paper I listed five adaptive functions that seemed to
me at the time to require a conscious mechanism:
Choice and the selection of action - short-term actions are
reviewed and selected, and possible and desirable outcomes and
possible alternative actions are consciously represented.
Modification and interrogation of long range plans - alternative
actions for long term plans are considered, and different
substructures and outcomes are evaluated. Retrieval from long-term
memory - explicit remembering is achieved, including the use of
simple addresses to access complex structures. Construction of
storable representations of current activities and events - (i)
social/cultural products are stored and retrieved, in part by the
use of language as an effective instrument for communication and
storage, and (ii) information is stored and retrieved for future
comparisons of present and past events. Troubleshooting -
representations and structures are brought into consciousness when
repair or emergency action is necessary on various - usually
unconscious - structures.
Over the next ten years I reconsidered more precisely what
functions need consciousness, i.e., that could not be performed
without some mechanism like consciousness. I also focused more on
automatic and simpler process, though I did pursue problems of
consciousness and memory in depth (Mandler, 1989). In a new book on
emotion (Mandler, 1984b) and a small volume on cognitive psychology
(Mandler, 1985, Ch. 3), I summarized a general view of unconscious
and conscious processes:
First, consciousness is limited in capacity and it is constructed
so as to respond to the current situational and intentional
imperatives.
Second, unconscious representations and processes generate all
thoughts and processes, whether conscious or not; the unconscious
is where the action is!
Third, all underlying (unconscious) representations are subject to
activations, both by external events and by internal (conceptual)
processes. The three levels of representation are: unconscious and
not recently activated; unconscious but activated (essential the
same as Freud's preconscious); and conscious.
Fourth, activated structures (e.g., schemas) are necessary for the
eventual occurrence of effective thought and actions. Only
activated structures can be used in conscious constructions.
Current models of schema theory and the more sophisticated, but
compatible, models of parallel distributed processes are all based
on these assumptions.
Fifth, and a new assumption, conscious events prime; they provide
additional activations to the relevant underlying structures.
Assumptions 2, 3, and 4 are shared by many cognitive scientists;
assumptions 1 and 5 need further elaboration. Both of them
emphasize more automatic than deliberate processes in
consciousness. That emphasis on automatic effects is found in
particular in an analysis of the feedback effects of conscious
contents. I shall discuss those at greater length later, but first
wish to talk about the construction of consciousness, in general,
as well as in the way it differs between daily life and dreams.
Constructive consciousness
The approach to consciousness developed by Marcel (1983b) has been
very useful to my thinking. Marcel was concerned with the
conditions under which mental structures reach the conscious state.
However, in contrast to the view that structures become conscious
so that consciousness is simply a different state of a structure,
Marcel sees consciousness as a constructive process in which the
phenomenal experience is a specific construction to which
previously activated schemas have contributed. Marcel specifically
rejected the identity assumption, which characterizes most current
views of consciousness. The identity assumption postulates that
some preconscious state "breaks through," "reaches," "is admitted,"
"crosses a threshold," "enters," into consciousness. A
constructivist position states, in contrast, that most conscious
states are constructed out of preconscious structures in response
to the requirements of the moment. I found this position
particularly attractive because it solved a problem that had
confronted me in my approach to emotion. If, as I had argued
(Mandler, 1975b) emotional experience has both physiological and
cognitive components, how are these combined into a single
emotional experience? The Marcel model which said that a particular
conscious state is constructed out of two or more preconscious ones
solved that problem for me (Mandler, 1984a). We are conscious of
experiences that are constructed out of two or more adequately
activated schemas that are not inhibited. We are not conscious of
the process of activation. The resulting phenomenal experience
makes "sense of as much data as possible at the highest or most
functionally useful level possible . . . ." (Marcel, 1983b).[5]
We are customarily conscious of the important aspects of the
environs, but never conscious of all the evidence that enters the
sensory gateways or of all our potential knowledge of the event. A
number of experiments have shown that people may be aware of what
are usually considered higher order aspects of an event without
being aware of its constituents. Thus, subjects are sometimes able
to specify the category membership of a word without being aware of
the specific meaning or even the occurrence of the word itself
(Marcel, 1983a; Nakamura, 1989). A similar disjunction between the
awareness of categorical and of event-specific information has been
reported for some clinical observations (Warrington, 1975).
This approach to consciousness suggests highly selective
constructions that may be either abstract/general or
concrete/specific, depending on what is appropriate to current
needs and demands. It is also consistent with arguments that claim
that we have immediate access to complex meanings of events. These
higher order "meanings" will be readily available whenever the set
is to find a relatively abstract construction, a situation frequent
in our daily interactions with the world. We do not need to analyze
the constituent features or figures to be very quickly
aware/conscious of the import of a picture or scene. In general, it
seems to be the case that "we are aware of [the] significance [of a
set of cues] instead of and before we are aware of the cues"
(Marcel, 1983b).[6]
Conscious constructions represent the most general interpretation
of the current scene that is consistent with preconscious
information and with the demands of the environment.[7] Thus, we
are aware of looking at a landscape when viewing the land from a
mountaintop, but we become aware of a particular road when asked
how we might get down or of an approaching storm when some dark
clouds "demand" inclusion in the current construction.
The construction of consciousness in daily
life
Constructive consciousness argues that current conscious contents
are responsive to the immediate history of the individual as well
as to current needs and demands.[8] We start with the (unconscious)
schemas that represent current mental life. Schemas are
dispositional mental structures that are constructed/assembled out
of distributed features. The unconscious mind is not a library of
static schemas, but rather an assemblage of features and attributes
that, on the basis of past experience and current activations,
produce appropriate mental structures. Currently available
information constructs (out of distributed features of previously
developed schemas) representations that respond both to the
immediate information and to regularities generated by past
experience and events. Evidence (occurrences) from both extra and
intra-psychic sources activates (often more than one) relevant
schemas. Concrete schemas, as well as " specific memories," will be
activated that represent objects and events in the environment and
in past experience. More abstract and generic schemas will be
activated by spreading activation; they may represent hypotheses
about external events and appropriate action schemas. These
assemblages of features and temporarily activated schemas provide
the building blocks for conscious representations. I will
experience (be conscious of) whatever is consistent with my
immediate preceding history as well as with currently impinging
events. The most important schemas that determine current conscious
contents are those that represent the demands and requirements of
the current situation.[9] The current situation activates and
constrains schemas (hypotheses) of possible actions, scenes, and
occurrences in terms of one's past experiences. In other words,
current conscious contents reflect past habits and knowledge in
addition to, and often instead of, the representations of the "real
world."
One of the best examples that conscious contents respond not merely
to "veridical" representations is shown by the work of Nisbett
& Wilson (1977). They show that conscious reconstructions of
previous events reflect not just what "actually happened," but also
respond to variables and structures of which we are not conscious
and which distort "veridicality." Distortions (constructions!) of
conscious memory, as for example in eyewitness testimony, provide
many instances of this process. Vibration induced illusions
(sensory misinformation) of limb motion produce novel but
"sensible" apparent body configurations, so that, for example,
biceps vibration of the arm while ones finger rests on one's nose
produces the experience of an elongated nose (see Lackner, 1988,
for this and many other examples). Similarly, misleading
information about one's hand movements apparently requires and
produces the experience of involuntary hand movements (Nielsen,
1963).
It is the hallmark of sane "rational" adults that they are
conscious of a world that is consistent with its usual constraints
as well as with the evidential constraints experienced by others in
the same situation and at the same time. But there is another
frequent human activity that is relatively unconstrained by
reality, yet is conscious - namely our nightly dreams.
Dreams, reality, and consciousness
In contrast to every day life, in dreams possible constructions are
only partially constrained by current reality and by the lawfulness
of the external world. But dreams are highly structured; they are
not random events. They present a structured mixture of real world
events, current events (sensory events in the environment of the
dreamer), contemporary preoccupations, and ancient themes. They may
be weird and novel, but they are meaningful. What they are not is
dependent on the imperatives and continuity of the real world -
inhabited by physically and socially "possible" problems and
situations. In the waking world our conscious experience is
historically bound, dependent on context and possible historical
sequences. In contrast, dreams do not depend on current sensory
activations; they are constructed out of previous activations.
Similar arguments have been made by others in somewhat different
contexts. Thus, "... in REM sleep the brain is isolated from its
normal input and output channels ... (Crick & Mitchison, 1983,
p. 112)." And Hobson, Hoffman, Helfand & Kostner (1987) note
that the brain/mind is focused in the waking state on the linear
unfolding of plot and time. In REM dreaming the brain/mind cannot
maintain its orientational focus. The leftovers of our daily lives
are both abstract themes - our preoccupations and our generic view
of the world - as well as concrete and specific activated schemas
of events and objects encountered. These active schemas are
initially not organized with respect to each other, they are - in
that sense - the random detritus of our daily experiences and
thoughts. Without the structure of the real world, they are free
floating. They are "free" to find accommodating higher order
structures. These may combine quite separate unrelated thoughts
about events, about happy or unhappy occurrences, but since there
are few real world constraints, they may be combined into sequences
and categories by activating any higher order schemas to which they
may be relevant.
It is in this fashion that abstract (and unconscious)
preoccupations and "complexes" may find their expression in the
consciousness of dreams. It is what Freud (1900/1975) has called
the "residue" of daily life that produces some of the actors and
events, whereas the scenario is free to be constructed by otherwise
quiescent higher order schemas. The higher order schemas - the
themes of dreams - may be activated by events of the preceding days
or they may be activated simply because a reasonable number of
their features have been left over as residues from the days
before. I should note that dream theories that concentrate only on
the residues in dreams fail to account for the obviously organized
nature of dream sequences - however bizarre these might be. In
contrast to mere residue theories, Hobson's activation-synthesis
hypothesis of dreaming (Hobson, 1988) supposes that, apart from
aminergic neurons, "the rest of the system is buzzing
phrenetically, especially during REM sleep" (Hobson, 1988, p.291).
Such additional activations provide ample material to construct
dreams and, as Hobson suggests, to be creative and to generate
solutions to old and new problems.[10]
This view is not discrepant with some modern as well as more
ancient views about the biological function of dreams (in modern
times specifically REM dreams), which are seen as cleaning up
unnecessary, unwanted, and irrelevant leftovers from daily
experiences. However, these views of dreams as "garbage collecting"
fail to account for their organized character (Crick &
Mitchison, 1984; Robert, 1886).
In short, dreams are an excellent example of the constructive
nature of consciousness: they are constructed out of a large
variety of mental contents, either directly activated or activated
by a wide ranging process of spreading activation, and they are
organized by existing mental structures.
I now turn to the issue of feedback, the effect of consciousness on
later constructions.
The feedback function of consciousness
The feedback assumption contrasts with the view that consciousness,
because phenomenal, cannot have any causal effects. Conscious
phenomena appear to occur after the event that they register (e.g.,
Gregory, 1981) and seem to be causally inert, i.e., [c]onsciousness
is not good for anything (Jackendoff, 1987, p.26). In contrast, the
feedback assumption asserts the causal utility of conscious events,
as well as their effect on subsequent activations of the
consciously represented events.
The feedback assumption states that the alternatives, choices, or
competing hypotheses that have been represented in consciousness
will receive additional activation and thus will be enhanced.[11]
Given the capacity limitation of consciousness combined with the
intentional selection of conscious states, very few preconscious
candidates for actions and thoughts will achieve this additional,
consciousness-mediated activation.[12] What structures are most
likely to be available for such additional activation? It will be
those preconscious structures that have been selected as most
responsive to current demands and intentions. Whatever structures
are used for a current conscious construction will receive
additional activation, and they will have been those selected as
most relevant to current concerns. In contrast, alternatives that
were candidates for conscious thought or action but were not
selected will be relegated to a relatively lower probability of
additional activation and therefore less likely to be accessed on
subsequent occasions.
The evidence for this general effect is derived from the vast
amount of current research showing that the sheer frequency of
activation affects subsequent accessibility for thought and action,
whether in the area of perceptual priming, recognition memory,
preserved amnesic functions, or decision making (for a summary of
some of these phenomena, see Mandler, 1989). The proposal extends
such activations to internally generated events and, in particular,
to the momentary states of consciousness constructed to satisfy
internal and external demands. Thus, just as reading a sentence
produces activation of the underlying schemas, so does (conscious)
thinking of that sentence or its gist activate these structures. In
the former case, what is activated depends on what the world
presents to us; in the latter the activation is determined and
limited by the conscious construction. Note that in order for the
feedback function to make sense, we must assume that the "adaptive"
function of construction that selects appropriate mental contents
is also operating.
This hypothesis of selective and limited activation of
situationally relevant structures requires no homunculus-like
function for consciousness in which some independent agency
controls, selects, and directs thoughts and actions that have been
made available in consciousness. Given an appropriate database, it
should be possible to simulate this particular function of
consciousness without an appeal to an independent decision-making
agency.
The proposal can easily be expanded to account for some of the
phenomena of human problem solving. I assume that activation is
necessary but not sufficient for conscious construction and that
activation depends in part on prior conscious constructions. The
search for problem solutions and the search for memorial targets
(as in recall) typically have a conscious counterpart, frequently
expressed in introspective protocols. What appear in consciousness
in these tasks are exactly those points in the course of the search
when steps toward the solution have been taken and a choice point
has been reached at which the immediate next steps are not obvious.
At that point the current state of world is reflected in
consciousness. That state reflects the progress toward the goal as
well as some of the possible steps that could be taken next. A
conscious state is constructed that reflects those aspects of the
current search that do (partially and often inadequately) respond
to the goal of the search. Consciousness at these points depicts
waystations toward solutions and serves to restrict and focus
subsequent pathways by selectively activating those that are
currently within the conscious construction. Preconscious
structures that construct consciousness at the time of impasse,
delay, or interruption receive additional activation, as do those
still unconscious structures linked with them. The result is a
directional flow of activation that would not have happened without
the extra boost derived from the conscious state.[13]
Another phenomenon that argues for the re-presentation and
re-activation of conscious contents is our ability to "think about"
previous conscious contents; we can be aware of our awareness.
There is anecdotal as well as experimental evidence that we are
sometimes confused between events that "actually" happened and
those that we merely imagined, i.e., events that were present in
consciousness but not in the surrounds. Clearly the latter must
have been stored in a manner similar to the way "actual" events are
stored (Anderson, 1984; Johnson and Raye, 1981). It has been argued
that this awareness of awareness (self-awareness) is in principle
indefinitely self-recursive, that is, that we can perceive a lion,
be aware that we are perceiving a lion, be conscious of our
awareness of perceiving a lion, and so forth (e.g., Johnson-Laird,
1983). In fact, I have never been able to detect any such extensive
recursion in myself, nor has anybody else to my knowledge. We can
certainly be aware of somebody (even ourselves) asserting the
recursion, but observing it is another matter. The recursiveness in
consciousness ends after two or three steps, that is, within the
structural limit of conscious organization.
The positive feedback that consciousness provides for activated and
constructed mental contents is, of course, not limited to
problem-solving situations. It is, for example, evident in the
course of self-instructions. We frequently keep reminding ourselves
(consciously) of tasks to be performed, actions to be undertaken.
"Thinking about" these future obligations makes it more likely that
we will remember to undertake them when the appropriate time
arrives. Thus, self-directed comments, such as, "I must remember to
write to Mary" or "I shouldn't forget to pick up some bread on the
way home," make remembering more and forgetting less likely. Such
self-reminding not only keeps the relevant information highly
activated but also repeatedly elaborated in different contexts,
thus ready to be brought into consciousness when the appropriate
situation for execution appears.[14] Self-directed comments can, of
course, be deleterious as well as helpful. The reoccurrence of
obsessive thoughts is a pathological example, but everyday
"obsessions" are the more usual ones. Our conscious constructions
may end up in a loop of recurring thoughts that preempt limited
capacity and often prevent more constructive and situationally
relevant "thinking." One example is trying to remember a name and
getting stuck with an obviously erroneous target that keeps
interfering with more fruitful attempts at retrieval. The usual
advice to stop thinking about the problem, because it will "come to
us" later, appeals to an attempt to let the activation of the
"error" return to lower levels before attempting the retrieval once
again. The fact that a delay may produce a spontaneous "popping" of
the required information speaks to unconscious spreading of
activation on the one hand and the apparent restricting effect of
awareness on the other (see Mandler, 1994, for extensive discussion
of these issues). Another example of the deleterious effects of
haphazard activation is represented in the likelihood of
consciousness being captured by a mundane occurrence. Thus, as we
drive home, planning to pick up that loaf of bread, conscious
preoccupation with a recent telephone call may capture conscious
contents to the exclusion of other, now less activated, candidates
for conscious construction, such as the intent to stop at the
store. Or, planning to go to the kitchen to turn off the stove, we
may be "captured" by a more highly activated and immediate
conscious content of a telephone call. The "kitchen-going"
intention loses out unless we refresh its activation by reminding
ourselves, while on the phone, about the intended task. If we fail
to keep that activation strong enough and the plan in mind -- our
dinner is burned.
The additional function of consciousness as outlined here is
generally conservative in that it underlines and reactivates those
mental contents that are currently used in conscious constructions
and are apparently the immediately most important ones. It also
encompasses the observation that under conditions of stress people
tend to repeat previously unsuccessful attempts at problem
solution. Despite this unadaptive consequence, a reasonable
argument can be made that it is frequently useful for the organism
to continue to do what apparently is successful and appears to be
most appropriate. Finally, the priming functions of consciousness
interact in important ways with its construction. If, as I have
argued, conscious construction response to (subjectively) important
aspects of the world, then it will be exactly those of course that
will be primed and enhanced for future use and access.
A waystation
Between 1986 and 1992 I had occasion to elaborate and consolidate a
number of old issues of capacity and seriality which resulted in my
current waystation of the bringing back - the redux - of
consciousness. Briefly, the issues on which I focused were these:
Given our recent insights into the parallel and distributed nature
of (unconscious) mental processing, the human mind (broadly
interpreted) needed to handle the problem of finding a buffer
between a bottleneck of possible thoughts and actions of comparable
"strengths" competing for expression and the need for considered
effective action in the environment. Consciousness handles that
problem by imposing limited capacity and seriality. Conscious and
unconscious processes are - in major ways - contrasted by their
differences in seriality and capacity. Conscious processes are
serial and limited in capacity to some 5 contemporaneous items or
chunks, whereas unconscious processes operate in parallel and are -
for all practical purposes - "unlimited" in capacity. Any
speculations about the evolution of consciousness needs to take
these distinctions into account.[15] And finally, given the
assumption that current conscious contents are constructed out of
available activated structures and current demands, it follows that
under different demands the same underlying structures should give
rise to different conscious representations (see Mandler, 1992).
To illustrate the importance of limited, serial conscious
representation, imagine consciousness as it is, behaving as yours
does, but with one - and only one - exception, namely its
seriality. Imagine consciousness as a parallel machine that permits
everything currently relevant (or unconsciously active) to come to
consciousness all at once. You would be overwhelmed by thoughts,
potential choices, feelings, attitudes, etc. of comparable
"strength" and relevance. As you read a book all the characters and
their implications would cascade in your mental life. Consider the
story of Lord Nelson and Lady Hamilton: As you read of one their
trysts you would also be aware/conscious of his victory at
Trafalgar, his defeats in the Mediterranean, his
anti-republicanism, his narcissism - and her eventual obesity, her
Lancashire beginnings, her lovers - and her husband's interest in
classical vases and volcanos, - and ..... .[16] A huge mishmash of
associations and ideas would envelop you, and that discounts simple
environmental events such as the chair you are sitting on, the lamp
that illumines your book, and so forth. A "humanly" impossible
situation. All of this would come in simultaneous snippets, still
constrained by the limited capacity of the machine. In this account
I have not relaxed the constraint of limited capacity. To relax
that restriction too, to permit all unconscious content to become
conscious might strain the capacity of the reader to suspend
disbelief. But wait just one more moment; would that consciousness
not remind you of a consciousness discussed in some other place? Is
that not a description of God - aware of all that all of "his
children" (including the merest sparrow) ever do and think. Can one
really move that easily move from humanity to deity - by just
suspending seriality, limited capacity, and the current relevance
of consciousness?
A minimalist conjecture and some interesting
problems
I want to summarize this discussion by suggesting that some minimal
number of assumptions and requirements might do justice to the
known functions of consciousness. Can we entertain an understanding
of conscious phenomena by considering only three basic functions of
consciousness:
a. The selective/constructive representation of unconscious
structures.
b. The conversion from a parallel and vast unconscious to a serial
and limited conscious representation.
c. The selective activation (priming) by conscious representations
that changes the unconscious landscape by producing new privileged
structures.
Of these processes, the priming function is more directly and
obviously associated with consciousness, whereas the others may be
more indirect and inferred. However, all of these characteristics
are amenable to empirical investigations, and in the end the
question is whether these minimalist assumptions are adequate to
handle the most obvious or inferred functions of consciousness. If
not, what else is needed, and is it consistent with these
assumptions? Or is there another core of assumptions that might
command assent from a large number of theorists.
Until that question can be settled (or even asked?), there are a
number of specific questions with which I have been concerned, and
which deserve further investigation.
Consciousness and short-term memory (STM). The distinction between
short-term and long-term memory goes back at least to the
beginnings of the information processing movement. Is it not about
time that we bring STM into line with what we know about
consciousness? William James coined the term "primary memory" to
designate information that is currently available in
consciousness.[17] If in STM we "retrieve" only whatever
consciousness will "hold," then we are limited to retrieving some
5+- items. The limitation is the same for STM and limited capacity
consciousness, both of which a restricted to a single organized set
with about 5 discernable constituent attributes, features, items,
etc. But any operation on the limited material held in
consciousness will further activate and bound that material,
providing a small set of highly activated preconscious
representations. Thus STM consists of "primary" currently conscious
contents and additional material that is very easily retrieved
because it is the product of these short term retrievals and
activations. In addition items "in" STM may have been elaborated or
merely activated, a difference that may determine their rate of
decay or accessibility.[18] Does this do justice to what we know
about STM?
Why is the limited capacity what it is? Whether one wishes to
define the limited capacity as 3 or 5 or 7 items/chunks, some such
magnitude has been accepted ever since George Miller's seminal
paper in 1956 on the "magical number." Of all the possible genetic
determinants of human cognition, the one that defines the limited
capacity of consciousness seems to demand more serious attention
than some of the more extravagant evolutionary conjectures that
circulate these days. It seems intuitively reasonable that the
number needs to be more than 2 and probably less than 10 if fast
decision processes on a reasonable number of alternatives are
required for survival. But why the number we've got?
How do we determine conscious contents? Nearly thirty years ago
Adrian (1966) noted that psychology's "uncertainty principle" may
well be the fact that the very interrogation of conscious contents
may alter these contents. Can we circumvent this problem? What
alternatives, such as Dennett's (1991) heterophenomenology, are
available?
Esoteric and other states of consciousness. Currently there is a
rather wide gulf between the cognitive science community on the one
hand and equally passionate investigators of esoteric and altered
states of consciousness on the other. Neither side seems to pay
much attention to what the other has to say, and given that we
speak from the cognitive science side it may be time to take a look
at the phenomena that the "others" cultivate. I tried to do that
early on (Mandler, 1975b) when I suggested that a variety of
different esoteric and meditative methods produce "conscious
stopping," i.e., a frame-freezing experience. How does that come
about?
On not being conscious. Patients with very dense amnesias have
given us some anecdotal guides on the experience of "not being
conscious." Tulving (1985) reports such a patient's description of
living in a permanent present and not being able to think about
future plans or events. More extensive follow-ups to these
interesting leads should be most useful for a better understanding
of "being conscious."
I want to conclude with comments on the place of consciousness in
the discussions of "mind," even though the confusion between the
two has created more heat than light.
The mind is what the brain does
Central to many disquisitions about consciousness are convoluted
arguments about the mind-body problem which demonstrate its utility
as a continuing mainstay of a philosophical cottage industry - - a
continuing preoccupation with the 19th century equation of mind and
consciousness. The very useful notion that the mind is what the
brain does[19] refers to the fact that we usually assign observed
or implied or subjectively reported behaviors of humans to some
intervening "mental" set of variables. At least since the end of
the 19th century, and surely, for most of the twentieth the term
mental has been applied to conscious and unconscious events, and to
a variety of theoretical machineries, ranging from hydraulic to
network to schematic to computational models. In recent years, the
last have achieved a unique status in the history of science as a
variety of philosophers and cognitive scientists have acted as if
the millennium had arrived and the final model that intervenes
between the brain and behavior has been found in the computer
analogy (cf. Dennett, 1991, Jackendoff, 1987).
There are specific, and sometimes very precise, concepts associated
with the function of larger units such as organs, organisms, and
machines, concepts that cannot without loss of meaning be reduced
to the constituent processes of the larger units. The speed of a
car, the conserving function of the liver, and the notion of a noun
phrase are not reducible to internal-combustion engines, liver
cells, or neurons. But nobody talks about the
Cadillac-acceleration, the liver-sugar, or the noun-phrase-cell
problem. Complex entities may develop new functions - a notion that
has sometimes been referred to as emergence. The mind has functions
that are different from those of the central nervous system qua
nervous system, just as societies function in ways that cannot be
reduced to the function of individual minds. This is, of course,
true even within bounded scientific fields; mechanics and optics
cannot be reduced to nuclear physics.
Some of the difficulty that has been generated by the mind-body
distinction stems from the failure to consider the relation between
well-developed mental and physical theories. Typically, mind and
body are discussed in terms of ordinary-language definitions of one
or the other. Because these descriptions are far from being
well-developed theoretical systems, it is doubtful whether the
problems of mind and body as developed by the philosophers are
directly relevant to the scientific distinction between mental and
physical systems.
Once it is agreed that the scientific mind-body problem concerns
the relation between two sets of theories, the enterprise becomes
theoretical and empirical, not metaphysical. And the conclusion
would be that we do not yet know enough about either system to
develop a satisfactory bridging system/language. If, however, we
restrict our discussion of the mind-body problem to the often vague
and frequently contradictory speculations of ordinary language,
then, as centuries of philosophical literature have shown, the
morass is unavoidable and bottomless.
For example, we can and do, in the ordinary-language sense, ask how
it is that physical systems can have "feelings." A recurring
philosophical blockbuster has been the question how a physical
brain can generate mental qualia such as color sensations. The
question has produced many premature explications, however
ingenious some of them are (such as Dennett's, 1991). A healthy
agnosticism, a resounding "I don't know" might be well-placed at
the beginning of these interchanges. We don't know, and we might
know sometime in the future, but is the question really different
from any other island of human ignorance? Such questions assume
that we know the exact nature of the physical system and of a
mental system that produces "feelings." Usually, however, the
question is phrased as if "feelings" were a basic characteristic of
the physical and mental system instead of one of its products. Not
only is the experience of a feeling a product, but its verbal
expression is the result of complex mental structures that
intervene between its occurrence in consciousness and its
expression in language. If we have truly abandoned Cartesian
dualism, then one may permit the question of how the brain "does"
consciousness, seen as just another thing that it does.
The study of consciousness also had a very modern hurdle in its
way. In their preoccupation with the computer analogy, many
cognitive scientists have become uneasy with consciousness as a
characteristic of one aspect of mind. In part because the problem
of computer consciousness is at the least complex (though not
difficult for science-fiction writers), some philosophers and
others have become closet epiphenomenalists - refusing to assign to
consciousness any function in mental life (e.g., Jackendoff, 1987;
Thagard, 1986 - who is however willing to let consciousness have
some functions in applied aspects of behavior!!).
Functionalism revisited - approaching
consciousness from the outside in
Assuming that the study of consciousness is important, how are we
to approach it? There have been two major trends in modern
treatments: Inside-out and Outside-in. The Inside-out approach
starts with the the appearance and characteristics of some human
action or behavior and then attempts to model a plausible mechanism
or set of mechanisms that will generate those characteristics. The
Outside-in theorist looks first at the functions of those human
actions and then attempts to find a plausible mechanism or
mechanisms that will carry out those functions. 20 The proverbial
Martian, on encountering an automobile, would - if an Insider -
immediately open the hood and try to understand the working of the
engine, but - if an Outsider - would first try to understand what
it is that automobiles do (and then open the hood). One of the
results of the Inside-out method is a very real attraction to
complex computational machines that can model some characteristics
of mind, but tend to be rather less able to carry out its
functions.
Dennett, for example, much like most philosophers, is primarily
concerned with the appearance and "feel" of consciousness and
becomes uncharacteristically vague when talking about its possible
functions (Dennett, 1991, pp.275 ff.; see also Mandler, 1993).
Another inside-out theorist is very specific in his defense of the
approach: Jackendoff (1987, p.327) rejects any inquiry as to what
functions consciousness might serve. He specifically endorses the
preferential use of evidence that is directed toward what
consciousness is, not what it is for. The attractiveness of the
inside-out/functionalism1 approach 21 is found in Chomsky's
approach to linguistics. Questions of the function of language are
secondary - in contrast to the linguistic "functionalists" who
preferentially consider contemporaneously several aspects of
language, including its communicative, cognitive, pragmatic, social
"functions" in order to understand its origin and structure. The
inside-out approach is also related to the preference for some sort
of central homunculus that directs and knows all. Not all homunculi
are bad, but this particular one usually adopts the language of the
board room, with "executives" directing "slaves" and similar
metaphors. It is, of course, inevitable that consciousness-talk at
the end of the 20th century will reflect 20th century mores and
prejudices, whether these are phrased in computer-language,
boardroom talk, or whatever. The best we can do is to be aware of
such obvious lures and to try to avoid evanescent sociocentric
approaches that are likely to have a relatively short life. On the
other hand, such pious exhortations may be useless since it is
highly probable that we cannot truly escape our current situation
and past history.
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