Part VI. Consciousness is functional.
?- ?
Chapter Ten
The functions of consciousness.
"The îparticulars of the distribution of consciousness,ï
so far as we know them, îpoint to its being efficacious.ï ... it
seems an organ, superadded to other organs which maintain the
animal in the struggle for existence; and the presumption of
course is that it helps him in some way in the struggle ..."
--- William James (1890, p. )
"Consciousness would appear to be related to the mechanism of
the body ... simply as a (by-)product of its working, and to be
completely without any power of modifying that working, as a
steam whistle which accompanies the work of a locomotive ... is
without influence upon its machinery."
--- Thomas Henry Huxley (18xx -
quoted in James, I, 130).
10.0 Introduction.
10.01 Conscious experience as a biological adaptation.
10.1 Definitional and Context©setting Function.
10.2 Adaptation and Learning Function.
10.3 Editing, Flagging and Debugging Function.
10.4 Recruiting and Control Function.
10.5 Prioritizing and Access Control Functions.
10.6 Decision-making and Executive Function.
10.7 Analogy-forming Function.
10.8 Metacognitive and Self©monitoring Function.
10.9 Autoprogramming and Self-maintenance Function.
10.99 Summary.
‹\ ‹
10.0 Introduction.
Readers who have come this far may be a bit skeptical about
Thomas Huxley's claim that conscious experience has no function
whatever in the workings of the nervous system. But the great
number of useful roles played by consciousness may still come as
a surprise. The eighteen or so functions presented in this
chapter provide only one way of grouping and labeling these
useful services --- some of the labels overlap, and there may be
some gaps. But it is doubtful whether any shorter list can do
justice to the great and varied uses of conscious experience.
The functions listed below (Table 10.1) really belong to the
entire GW system, including both conscious and unconscious
components. In this architecture conscious experience represents
the jewel in the crown, enabling the whole system to function.
10.01 Conscious experience as a biological adaptation.
A basic premise of this book is that, like any other
biological adaptation, consciousness is îfunctionalï. Many
biological mechanisms recruit multiple functions: the eyes pick
up information in the light, but human eye-contact also
communicates social messages like dominance, submission,
affection, and plain curiosity. Consciousness, too, has
apparently gathered multiple functions in its evolutionary
history; we explore some of these functions in this chapter (e.g.
Rozin, 1976; Baars, in press, b). But perhaps the most
fundamental function is the one we remarked on in Chapter One:
the ability to optimize the trade©off between organization and
flexibility. Organized responses are highly efficient in well™known
situations, but in cases of novelty, flexibility is at a
premium. Of course the global workspace architecture is designed
to make "canned" solutions available automatically in predictable
situations, and to combine all possible knowledge sources in
unpredictable circumstances.
In another way, consciousness and related mechanisms pose a
great challenge to functional explanations because of the
paradoxical limits of conscious capacity (1.zz). Why can't we
experience two different "things" at one time? Why is short-term
memory limited to half a dozen unrelated items? How could such
narrow limits be adaptive? Naively, it would seem wonderful to be
able to consciously read one book, write another one, talk to a
friend, and appreciate a fine meal, all at the same time.
Certainly the nervous system seems big enough to do all these
things simultaneously. The usual answers, that the limitations
are "physiological," or that we only have two hands and one mouth
to work with, are quite unsatisfactory because they simply move‹j ‹
the issue one step backwards --- why have organisms blessed with
the most formidable brain in the animal kingdom not developed
hands and mouths able to handle true parallel processing? And why
does our ability to process information in parallel increase with
automaticity, and decrease with conscious involvement?
Whenever we encounter a biological phenomenon that seems
non-functional there are two possible explanations. First, we may
be asking the wrong question: perhaps cultural evolution has
simply outpaced biological evolution, and we are now expecting
the organism to do things it was not adapted to do. It is a good
bet that the nervous system was not developed for academic study,
since universal education is only a few centuries old in almost
all cultures. This may be the reason that learning in school
seems so hard, while learning to perceive the world, learning to
move, or learning one's native tongue seem effortless by
comparison. If we then ask why children find it hard to learn
arithmetic or spelling, we are asking a culturally biased
question, one that may seem natural today, but which is
biological nonsense.
A second reason for apparently non-functional adaptations
may be an invisible "design trade-off" between two different
factors (e.g. Gould, 1982). When the mammalian ancestors of the
whales returned to the ocean, they must have encountered trade-
offs between walking and swimming, and over time lost their legs.
This may seem non-functional to land animals like ourselves, but
the loss was compensated by a great gain in swimming ability.
Conscious limited capacity may involve such a trade-off. There
may be powerful advantages for a global broadcasting ability that
allows access from îanyï component of the nervous system to îall
otherï components. A truly global message, if it is to be
available to any part of the nervous system, must come only one
at a time, because there is only one "whole system" at any moment
to receive the message. Thus, in a sense, vertebrates evolved a
nervous system with two operating modes: a parallel (unconscious)
mode and a serial (conscious and limited-capacity) mode. GW
theory gives one interpretation of the interaction between these
dual operating modes.
Biological adaptations tend to be accretive (Gould, 1982;
Rozin, 1976). The speech system, for example, is "overlaid" on a
set of organs that in earlier mammals supports breathing, eating,
and simple vocalization. Likewise, it may be that the global
broadcasting property of the consciousness system is overlaid on
an earlier function that is primarily sensory. This may be why
human consciousness has such a penchant for sensory, perceptual,
and imaginal contents compared to abstract or non-qualitative
events (e.g. 2.xx).
Following is the most plausible story we can tell about the
uses of consciousness, based on the foregoing chapters.
‹j ‹
îTable 10.1ï
The major functions of consciousness
------------------------------------
1. îDefinition and Context©setting.ï By relating global input to
its contexts, the system underlying consciousness acts to
define the input and remove ambiguities. Conscious global
messages can also evoke contexts, which then constrain later
conscious experiences.
2. îAdaptation and Learning.ï Conscious experience is needed
to represent and adapt to novel and significant events.
3. îEditing, Flagging, and Debugging.ï Unconscious processors
can monitor any conscious content, edit it, and try to change
it, if it is consciously "flagged" as an error.
4. îRecruiting and Control Functions.ï Conscious goals can
recruit subgoals and motor systems, to organize and carry out
mental and physical actions.
5. îPrioritizing and Access-Control.ï Attentional mechanisms
exercise conscious and unconscious control over what will
become conscious. By relating some particular conscious
content to deeper goals, we can raise its access priority,
making it conscious more ofen and increasing the chances of
successful adaptation to it.
6. îDecision-making or Executive Function.ï When automatic
systems cannot routinely resolve some choice-point, making
it conscious helps recruit unconscious knowledge sources
to help make the proper decision. In the case of indecision,
we can make a goal conscious to allow widespread recruitment
of conscious and unconscious "votes" for or against it.
7. îAnalogy-forming Function.ï Unconscious systems can search for a
îpartialï match between their contents and a globally displayed
(conscious) message. This is especially important in
representing new information, when no close models of the
input are available.
8. îMetacognitive and Self©monitoring Function.ï Through conscious
imagery and inner speech we can reflect upon and control our
own conscious and unconscious functioning.
9. îAutoprogramming and Self-maintenance Function.ï The deeper
layers of context can be considered as a "self-system", which
works to maintain maximum stability in the face of changing
inner and outer conditions. Conscious experience provides
information for the self-system to use in its task of
maintaining stability. By "replaying" desirable goals, it can
recruit processors able to produce solutions and thereby
reprogram the system itself. ‹j ‹å
10.1 îDefinitional and Context©setting Function.ï
In looking through a hollow tube at an isolated corner of a
room (1.xx), in listening for the words in a rock song, or in
learning to perceive an abstract painting, we engage in conscious
observation leading to an experiential transformation. We may
experience this transformation directly, simply by attending to
the stimulus until it is transformed. But even when we try to
understand an easy sentence, rapid transformations are taking
place unconsciously: many different unconscious sources of
information combine to build a single interpretation of a focal,
rather ambiguous event (Tanenhause, etc.).
If we were forced to choose one premier function of
consciousness, it would be the ability of the consciousness
system to combine a variety of knowledge sources in order to
îdefineï a single, coherent experience. Another way to say this is
that the system underlying consciousness has the function of
relating an event to the three kinds of contexts: to a
qualitative context that allows us to experience an event as an
object of consciousness, to a conceptual interpretation, and to a
goal context that may lead to effective action (Chapters 4, 6,
and 7). A word can be experienced without a conceptual context,
but such a context is necessary for it to have meaning; and we
know that a meaningful word is generally related to some
contextual goals, which are not wholly available consciously at
the time they guide us. This contextual apparatus is needed to
allow even very "simple" things to take place, such as the
reader's decision to read the next paragraph.
A related, critical function of consciousness is to evoke
relevant contexts in the first place. This is most obvious in the
case of conceptual and goal contexts; for example, in the case of
the Tip©of©the©Tongue (TOT) phenomenon, where the role of a goal
context is quite clear (4.xx). Given the TOT state, we begin to
search (unconsciously) for the correct word; this search process,
and the goal context of retrieving the word, together will
constrain the conscious answers that will come to mind. Context™setting
may not be so clear in more complex cases, like meeting a
new person, or encountering a new idea, but conscious experiences
in these cases do seem to evoke and create new contexts.
10.2 Adaptation and Learning Function.
Whether consciousness is înecessaryï for learning has led to
years of controversy (e.g. Eriksen, 1962; Holender, 1986). But
there is little doubt that the more novel the material to be‹j ‹
learned, the more time we must typically spend pondering it
consciously before learning to cope with it (5.xx). GW theory
suggests that conscious events are broadcast globally to
unconscious processors and contexts, which can then adapt to this
information. If they cannot adapt immediately, they can act to
bring the material to mind at some later time, sometimes many
times. Several researchers have shown that personally significant
information tends to come to mind again and again, until
presumably it is absorbed and adapted to (Singer, 1984; Horowitz,
1975 ab; Klinger, 1971). Obviously we also adapt to the world by
action: we can avoid a threatening predator, approach a new
source of food, and explore an unusual situation. Action also
requires conscious goal images, which must, again, be more
consciously available the more novel the action is (7.xx).
10.3 Editing, Flagging and Debugging Function.
Several psychologists have argued that conscious experience
plays a role in "debugging" faulty processes (e.g., Mandler,
1975). In particular, it seems that conscious events are
monitored by numerous unconscious rule-systems that can compete
for access to the Global Workspace if they detect some serious
flaw, and which may be able to cooperatively improve the flaw
(7.xx). Indeed, we have argued in Chapter 7 that voluntary action
îisï tacitly edited action. On the other side, conscious experience
can also be used to "flag" some significant event. The most
spectacular example of this is biofeedback training, in which
otherwise unconcious events can come under voluntary control
simply by having the unconscious event trigger a conscious
feedback signal. In this way we can learn to control apparently
any population of neurons at least temporarily (2.x). Biofeedback
training reveals an extraordinary capacity of the nervous system,
one that by itself suggests the existence of global broadcasting.
10.4 Recruiting and Control Function.
Recruiting has much to do with the Flagging Function --- in
fact, as soon as we can flag some novel mental event consciously,
we may be able to recruit it for voluntary purposes. The
ideomotor theory (7.xx) suggests that conscious goal images are
necessary to recruit subgoals and motor systems that will achieve‹j ‹
the goal. But of course conscious goal images themselves are
under the control of unconscious goal contexts, which serve to
generate the goal image in the first place.
The Control Function is similar to the notion of Recruiting
of unconscious systems to help in achieving a goal. But
consciousness is useful in setting goals in the first place, and
in monitoring action feedback for success or failure. To set a
goal that is compatible with existing goal contexts, we need to
simply become conscious of the goal. Thus: "what is the name of
the first President of the United States?" Just being conscious
of the question allows the answer to be searched for
unconsciously, and candidate answers are returned to
consciousness, where they can be checked by multiple unconscious
knowledge sources. Feedback checking occurs in essentially all
tasks, from striking a tennis ball to checking the loudness of
one's voice, to word-retrieval, to mental arithmetic. In all
these cases it is useful for errors to become conscious, in order
to recruit unconscious error- detection and correction resources.
10.5 Prioritizing and Access Control Functions.
Attention involves access control to consciousness, and
assigning priorities is a core issue in access control.
Incomplete conscious thoughts tend to evoke conscious. We can
apparently use conscious functions to control the likelihood that
some piece of information will become conscious more often.
Presumably, in the act of voluntarily accessing some information,
we also practice the skill of recalling it --- i.e., of making it
conscious again (8.0). In vocabulary development we may want to
practice certain words to ensure that they will come to mind
readily when needed. Recall as the skill of bringing material to
consciousness has been studied since Ebbinghaus, but most modern
studies ignore the fact that "recall" îmeansï "bringing memories to
consciousness."
We can change the access priority of information in several
ways. One way is to use associative learning techniques, like
paired associate learning. If a neutral conscious event is made
to signal a horrifying mental image, the neutral event will take
on a higher priority (presumably it has more activation, or it is
associated with a higher©level goal context), which will make it
more easily available to consciousness.
10.6 Decision-Making or Executive Function.
While the global broadcasting system is not an executive
mechanism, it can be îused byï goal systems in an attempt to
control thought and action. Chapters 6 - 9 are really devoted to
different aspects of this issue. Consciousness can serve as the
domain of competition between different goals, as in
indecisiveness and conscious, deliberate decisions. In a sense,
one can broadcast the goal, "Should I ... ?" followed by "Or
shouldn't I ...?" and allow a coalition of systems to build up in
support of either alternative, as if they were voting one way or
another. The successful coalition presumably supports a goal
image that is broadcast without effective competition, and which
therefore gains ideomotor control over the action (7.0). This may
be called the Decision-Making function of conscious experience.
Goal images do not have to be recallable as conscious in
order to influence action. There is considerable reason to
believe that fleeting, hard-to-recall goal images can trigger off
well-prepared automatisms (1.xx; 7.x). These images then act in
an Executive fashion without allowing conscious decision-making;
of course, the executive goal images may themselves be generated
by complex unconscious goal structures.
10.7 Analogy-Forming Function.
Human beings have a great penchant for analogy and metaphor,
and we use this capacity especially to cope with novel or
ill-comprehended situations. Lakoff & Johnson () point out that
most everyday idioms involve a metaphorical extension from a
well-known, concrete situation to one that is abstract or poorly
understood. Thus, "the mind is a container," "love is a journey,"
and "consciousness is the publicity organ of the nervous system."
Metaphors are both useful and dangerous. In science we use them
constantly, and we must be ready constantly to abandon them when
they lead us astray. The Rutherford atom of 19th century physics
drew an analogy between the planets around the sun and electrons
orbiting a heavy nucleus. Here the similarities and differences
are obvious in retrospect; but at the time, of course, one did
not know how far the metaphor would work, and where it would have
to be abandoned. But it gave one a start. Similarly, whenever we
encounter something new, something for which our existing
knowledge is inadequate, we look for partial matches between the
novel case and existing knowledge. Such partial matches invite
metaphors. We can best manipulate those metaphors that are
familiar and easy to visualize. Thus we tend to concretize
abstract entities and relationships, and thereby transfer our
knowledge from one context to another.
The GW system is useful at several points along this path.‹j ‹
It helps in detecting partial matches. It allows many systems to
attempt to match a global message, and to display their partial
matches globally. It supports competition beween different
systems to edit the mental model of the event that is to be
understood. And, in its preference for imageable, qualitative
experiences, it is probably responsible for the bias for
concreteness and imageability that we find in human metaphor.
Indeed even when we have accurate abstract representations
of some information, we still prefer less accurate prototypes and
metaphors. We know that the average chair is înotï the prototypical
square, brown, wooden, lacquered kitchen chair, yet we continue
to use the false prototype, apparently because we have easier
conscious access to it than to the more realistic abstraction
(Rosch, 1975).
10.8 Metacognitive or Self©monitoring Function.
Conscious metacognition depends on the ability of one
experience to refer to other experiences. Normally when we speak
of consciousness we include the ability to describe and act upon
our own conscious contents. Indeed, the operational definition of
conscious experience proposed in Chapter 1 is predicated upon
this ability (1.x). But conscious metacognition îitselfï requires
the global workspace and consciousness (8.xx). Another aspect of
such a self-referring system is our ability to label our own
intentions, expectations, and beliefs, all abstract
representations that are not experienced directly in the way
qualitative percepts or images are. Nevertheless, people
constantly refer to their own intentions as if they were discrete
objects in the world.
Conscious self©monitoring is perhaps the single most
important aspect of metacognition. There is a great deal of
evidence for the view that many adults are constantly monitoring
their own performance by reference to some set of criteria that
can be collectively labeled the "self©concept." We might expect
self©monitoring to play a role in the psychology of impulse
control --- if one has an impulse to do something questionable,
and if one can internal competition against it, to hold the
action in abeyance, chances for control are improved. There is
direct evidence that impulsive children can be taught to use
inner speech in such a self©monitoring fashion, and that this
does indeed help to constrain inappropriate actions (Meichenbaum
& Goodman, 1971).
‹j ‹å 10.9 Autoprogramming and Self-maintenance Function.
We can ask the reader to pay attention to the period at the
end of this sentence. We can ask someone to retrieve a memory, to
solve a puzzle, or to wiggle a finger. We can learn new habits.
All this implies the ability of the conscious system to engage in
self-programming. In autoprogramming, goal systems make use of
conscious experiences to exercise some control over both
conscious and unconscious events. Autoprogramming can encounter
obstacles, as in attempts to control smoking, over-eating, or
other undesired habits, but it is often quite effective. It
presumably combines many of the functions discussed before:
context©setting, decision©making, self©monitoring, etc.
The smooth functioning of the whole system is dependent upon
a stable Dominant Goal Hierarchy, the deeper levels of which
apparently correspond to the "self" of common sense psychology.
These deeper levels can be violated by external circumstances,
just as any other contextual constraints can be. In addition,
there is much clinical experience to suggest that the self can
encounter violations of internal origin. Maintaining the self™system may be critical for
mental and physical survival, and one
tool for doing so may be the attentional control for access to
consciousness. The classical notions of repression would seem to
fit in here. The evidence for repression as an unconscious
process has been questioned (e.g. Holmes, 1972, 1974), but there
is no dispute over the great amount of self©serving ideation and
control of access to conscious experience that people engage in.
The evidentiary question centers mainly about the issue whether
this kind of control is voluntary and conscious or not. GW theory
suggests that this is a secondary issue, since predictable
voluntary control tends to become automatic with practice. In any
case, Self©maintenance through the control of access of
information to consciousness seems to be one central role of the
consciousness system.
10.99 Summary.
Conscious processes are functional, just as unconscious ones
are. Normal psychology involves a rapid, delicate interplay
between conscious and unconscious events. Our list of eighteen
functions does not exhaust the possibilities: for example, we
have not even touched on the uses of sleep and dreaming. They too
must surely have some functional role, probably even multiple
roles, which are likely to be bound up with the system we have
explored in this book. But this issue must be left for future
exploration, along with so many others.
No doubt there will be some who continue to advocate the
curious doctrine of epiphenomenalism, the idea that conscious‹j ‹
experience has no function whatsoever. All we can do is point to
the evidence, and develop further demonstrations that loss of
consciousness through habituation, automaticity, distraction,
masking, anesthesia, and the like, inhibits or destroys the
functions listed here.
Some epiphenomenalists seem to adopt their position to
defend the special and unique status of conscious experience.
They are right. Consciousness îisï special. But its wonderful
qualities are not isolated from other realities; nor is
biological uselessness a special virtue. Consciousness is the
vehicle of our individuality, something that makes it of
inestimable significance to each of us. But viewed from the
outside, as an element in a larger system, the marvel of
consciousness is one more wonder in an awesome nervous system,
supported by a body that is scarcely less wonderful, evolved and
maintained in a biosphere of endless complexity and subtlety, in
a universe one of whose most miraculous features, as Einstein has
said, is our ability to know it.