JCS, 4 (4), 1997, pp. 292-309
Baars, B.J. The Wright Institute, 2728 Durant Ave., Berkeley,
California 94704, USA baars@cogsci.berkeley.edu
Can we make progress exploring consciousness? Or is it forever beyond
human reach? In science we never know the ultimate outcome of the journey.
We can only take whatever steps our current knowledge affords. This paper
explores today's evidence from the viewpoint of Global Workspace (GW) theory.
First, we ask what kind of evidence has the most direct bearing on the
question. The answer given here is `contrastive analysis' -- a set of paired
comparisons between similar conscious and unconscious processes. This body
of evidence is already quite large, and constrains any possible theory
(Baars, 1983; 1988; 1997). Because it involves both conscious and unconscious
events, it deals directly with our own subjective experience, as anyone
can tell by trying the demonstrations in this article.
One dramatic contrast is between the vast number of unconscious neural processes happening in any given moment, compared to the very narrow bottleneck of conscious capacity. The narrow limits of consciousness have a compensating advantage: consciousness seems to act as a gateway, creating access to essentially any part of the nervous system. Even single neurons can be controlled by way of conscious feedback. Conscious experience creates access to the mental lexicon, to autobiographical memory, and to voluntary control over automatic action routines. Daniel C. Dennett has suggested that consciousness may itself be viewed as that to which `we' have access. (Dennett, 1978) All these facts may be summed up by saying that consciousness creates global access.
How can we understand the evidence? The best answer today is a `global workspace architecture', first developed by cognitive modelling groups led by Alan Newell and Herbert A. Simon. This mental architecture can be described informally as a working theatre. Working theatres are not just `Cartesian' daydreams -- they do real things, just like real theatres (Dennett & Kinsbourne, 1992; Newell, 1990). They have a marked resemblance to other current accounts (e.g. Damasio, 1989; Gazzaniga, 1993; Shallice, 1988; Velmans, 1996). In the working theatre, focal consciousness acts as a `bright spot' on the stage, directed there by the selective `spotlight' of attention. The bright spot is further surrounded by a `fringe,' of vital but vaguely conscious events (Mangan, 1993). The entire stage of the theatre corresponds to `working memory', the immediate memory system in which we talk to ourselves, visualize places and people, and plan actions.
Information from the bright spot is globally distributed through the theatre, to two classes of complex unconscious processors: those in the darkened theatre `audience' mainly receive information from the bright spot; while `behind the scenes', unconscious contextual systems shape events in the bright spot. One example of such a context is the unconscious philosophical assumptions with which we tend to approach the topic of consciousness. Another is the right parietal map that creates a spatial context for visual scenes (Kinsbourne, 1993). Baars (1983;1988; 1997) has developed these arguments in great detail, and aspects of this framework have now been taken up by others, such as the philosopher David Chalmers (1996). Some brain implications of the theory have been explored. Global Workspace (GW) theory provides the most useful framework to date for our rapidly accumulating body of evidence. It is consistent with our current knowledge, and can be enriched to include other aspects of human experience.
JCS, 4 (4), 1997, pp.310-13
Cisek, P.E., Département de Physiologie, Université
de Montréal, Montréal, (Québec) H3C 3J7 Canada.cisekp@ere.umontreal.ca
The global workspace architecture is examined from an evolutionary
perspective. It is argued that certain aspects of the theory are difficult
to account for in terms of a sequence of evolutionary elaborations. These
notably include distinct actors and audience members, and the lingua
franca by which they communicate. An alternative metaphor of a `global
arena' is suggested, along with speculation on how this bottleneck of behavioural
competition may have evolved toward a more sophisticated architecture,
perhaps even a theatre . . .
JCS, 4 (4), 1997, pp.314-16
Combs, A., Dept. of Psychology, CPO #1960, University of North Carolina Asheville, NC 28804-8508, USA. Email combs@unca.edu
JCS, 4 (4), 1997, pp. 316-18
Dalton, J.W., The University of Edinburgh, 80 South Bridge, Edinburgh
EH1 1HN, Scotland. J.Dalton@ed.ac.uk
Can we understand conscious experience? It can seem that the answer
is `no'. Even when we have well-supported cognitive accounts of consciousness,
such as global workspace theory, experience itself seems to elude our grasp.
It is easy to see how a global workspace might be a useful adaptation,
much harder to see what role is played by conscious experience. For instance,
if I'm looking for a blue notebook, why do I need to experience colours?
Why wouldn't it suffice to have an unconscious mechanism that recognized
colours, and could make such information available to other systems? Why
couldn't the mechanisms of the workspace operate without experience at
all?
JCS, 4 (4), 1997, pp.319-24
Elitzur, A.C., School of Physics and Astronomy, The Raymond and
Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, 69978 Tel-Aviv,
Israel. cfeli@weizmann.weizmann.ac.il
Baars' (1997a,b) Global Workspace theory suggests that consciousness
functions as a gateway, facilitating focused access to any part of the
brain. While this hypothesis does not address the `hard problems', namely,
the very nature of consciousness, it constrains any theory that attempts
to do so and provides important insights into the relation between consciousness
and cognition. Many questions have found new answers once they were turned
upside down. In medicine, for example, important discoveries have been
made when, instead of asking `Why did this disease inflict this person
now?' someone rather asked `Why doesn't this disease always inflict all
people?' Bernard Baars (1997a,b) tries to do something similar with the
mind-body problem. Whereas most people often ask, `Why are there conscious
experiences accompanying some brain processes?', he asks, `Why aren't there
conscious experiences accompanying all brain processes?'
JCS, 4 (4), 1997, pp.322-4
Franklin, S., Institute for Intelligent Systems, The University
of Memphis, Memphis, TN 38152, USA. stan.franklin@memphis.edu
In the target article, Baars has offered both a theory of consciousness
and a strategy for scientifically testing the theory. This commentary is
intended as an addendum. I'd like to suggest implementing global workspace
agents as both an additional strategy toward scientific testing, and as
a means of fleshing out the theory.
JCS, 4 (4), 1997, pp.325-9
Haarmann, H.J., Department of Psychology, Carnegie Mellon University,
Pittsburgh, PA 15213, USA. hh2h@andrew.cmu.edu
The Global Workspace theory of consciousness (GW) explains conscious-unconscious
dichotomies in cognitive processing in the context of a proposal about
the qualitative properties of the architecture of cognition (Baars, 1988;
1997). This represents a theoretical and methodological approach to the
study of consciousness which, as I will argue in this commentary, has at
least two major advantages. A first advantage is that GW theory as a proposal
about the architecture of cognition has the potential to explain consciousness-related
phenomena in mechanistic terms, thereby avoiding the homunculus problem.
A second advantage is that GW theory makes explicit use of conscious-unconscious
dichotomies to specify a proposal about the architecture of cognition,
thereby using an extra source of constraint which proponents of computational
instantiations of such architectures have largely ignored in the past (e.g.
Anderson, 1993; Just & Carpenter, 1992; Newell, 1990).
JCS, 4 (4), 1997, pp.329-31
Hiley B.J., Physics Department, Birkbeck College, Malet Street London
WClE 7HX, UK.
JCS, 4 (4), 1997, pp.332-4
Osaka, N., Department of Psychology, Graduate School of Letters
Kyoto University,Kyoto 606, Japan. osaka@kupsy.kyoto-u.ac.jp
The target article by Bernard Baars (1997b) presents a quick way of
grasping the gist of his book In the Theater of Consciousness: The Workspace
of the Mind, published recently (Baars, 1997a). The metaphor of consciousness
as a theatre has a long history. A prototype of the theatre model may be
traced back to Plato's Allegory of the Cave, in which we are like prisoners
living in a cave just observing the shadows of reality. The modern theatre
model insists on consciousness being under the control of attention by
introducing a searchlight metaphor (Crick, 1984; Baars, 1988). The target
article explores some evidence from the viewpoint of Global Workspace (GW)
theory by using a method of `contrastive analysis'. According to this theory,
GW works as the publicity organ of the brain and has a facility for accessing,
disseminating, and exchanging information, and for exercizing global coordination
and control (Baars, 1997b). Baars describes his GW as a theatre. `As the
house lights begin to dim and the audience falls silent, a single spotlight
pierces the descending darkness, until only one bright spot, shining on
stage, remains visible. You know that the audience, actors, stagehands,
and spotlight operators are there, working together under invisible direction
and guided by an unknown script, to present the flow of visible events
on stage. As the house lights dim, only the focal contents of consciousness
remain. Everything else is in darkness' (Baars, 1997a, p. 41). According
to GW theory, a theatre stage with a bright spot is just a working memory.
So I would like to comment on some general characteristics of the working
memory and related spotlight problem.
JCS, 4 (4), 1997, pp.334-7
Rockwell, T., 2419A Tenth Street, Berkeley, CA 94710, USA 74164.3703@compuserve.com
Surprisingly, Dennett and Baars have no real quarrel with each other,
despite the fact that Dennett wants to escape from the Theatre of Consciousness
and Baars is happy to stay there. Both believe that consciousness has structures
that can be analysed, and is not just `the mysterious glow that no one
but me can see' described by Chalmers and Searle. Both acknowledge that
their theories of consciousness are only metaphors, and there is no conflict
in saying that Consciousness is both like a theatre and like a series of
multiple drafts. And both Dennett and Baars would agree that Consciousness
seems to be like a theatre. Their main disagreement is how deep the similarity
goes, and whether the similarity is more misleading than useful. There
are other scientific controversies that could probably be dissolved by
such an ecumenical attitude: there is no paradox in saying that an electron
is both like a wave and like a particle, or that thought is both like a
language in the head and like a connectionist network. But a non-aggression
pact of this sort does not absolve us from enumerating the ways in which
each of these metaphors does and does not map onto its object. And as this
enumeration continues, it is likely to make one of these metaphors seem
more plausible than the other.
JCS, 4 (4), 1997, pp.337-9
Taylor, J.G., Centre for Neural Networks, Dept of Mathematics, King's
College, Strand, London, WC2R 2LS, UK
JCS, 4 (4), 1997, pp.339-44
Underwood, G., Paterson, K. and Chapman, P., Department of Psychology,
University of Nottingham, Nottingham NG7 2RD, UK gju@psychology.nottingham.ac.uk
The essence of Baars' (1997) paper is to propose nine functions for
consciousness. By way of introducing these functions we are presented with
a metaphor of a theatre, in which players act, operators set contexts behind
the scenes, an unconscious audience provides specialised capabilities,
and, of course, a bright spotlight of attention illuminates whatever is
available to consciousness. The value of this metaphor is not entirely
clear, with the separate `roles' of the audience and of the operators behind
the scenes being particularly difficult to identify. Additionally, there
may be a problem with idea that there is some kind of competition between
actors who are seeking the spotlight of attention, for this suggests that
the components of thought have volitions of their own. These would, indeed,
be dangerous thoughts.
Rather than attempting an analysis of the metaphor and its potential usefulness, this commentary will consider the nine functions of consciousness that have been proposed.
JCS, 4 (4), 1997, pp.344-6
Varela, F.J., Cognitive Neuroscience Laboratory Salpetriere Hospital-CNRS,
Paris fv@ccr.jussieu.fr
Baars (1997) presents a clear and productive approach to consciousness
as a scientific issue. My commentary is motivated by this positive assessment
in order to underline what I see as important limitations in the sketch
we are presented with, and which are close to my own research interests.
I will concentrate only on two fundamental questions here: (1) the still
misleading nature of the theatre metaphor for consciousness in spite of
Baars' radically new interpretation; (2) the still unexamined naïvité
in regards to question of methodologies of access to experience, in spite
of Baars' avowed interest in linking to first-person experience.
JCS, 4 (4), 1997, pp.365-73
Johnston, P.K., Dept. of English, SUNY Plattsburgh, Plattsburgh,
NY 12901, USA.
Many avenues lead to human consciousness: introspection, phenomenology,
cognitive science, philosophy, neurobiology. To these can be added aesthetics;
both the production of artful objects and the appreciation of artful objects
are characteristic of human minds. By looking at artful objects we can
hypothesize why the human mind both produces them and responds to them,
and derive from such hypotheses ideas about the nature of human consciousness,
including its power to make present in the mind that which is absent from
view. In particular, the art of Shakespeare, being both verbal and formal,
both articulates the peculiar burdens of human consciousness and demonstrates
art's response to these burdens. His play Troilus and Cressida serves
as an example, exhibiting and exploring the discordancies human consciousness
is liable to, and at the same time incorporating those discordancies into
a greater harmony through the formal structures of art.
JCS, 4 (4), 1997, pp. 374-5
Libet, B., Department of Physiology, University of California at
San Francisco
See
also special offer on new subscriptions
Home
page
