COGNITIVE THEORIES OF
Room T10, William Guild Building
What function does consciousness perform?
• Baar‟s Global Workspace Theory
• Dennett‟s Multiple Drafts Theory
• Shanon‟s Theory
• All three models share the assumption that human
consciousness is not unitary in nature.
Global Workspace Theory
• Bernard Baars (1988; Baars et al., 1998) argues
that the function of consciousness is to broadcast
information to separate functional modules
through-out the brain.
• His „global workspace‟ is a central processor
that contains the contents of consciousness.
• The Workspace functions as a cognitive
Consciousness as a „Theatre‟
• Baar‟s theory addresses the problem of
• Consciousness is enabled by working
memory, which provides a means to
control what information can become
• To explain his theory Baar uses the
analogy of consciousness as a ‘theatre’.
• Working memory provides the „stage‟ of
• We only become conscious of information
held in working memory if it is selected
by the central executive.
• Central idea of Baar‟s theory is that once a
representation becomes conscious it
becomes available to other cognitive
• Baar‟s theory does not address the
problem of phenomenal consciousness
(i.e., Chalmer‟s „hard‟ problem).
Multiple Drafts Theory
• Daniel Dennett argues in his book
Consciousness Explained (1991) that
consciousness is not an all-or-nothing
phenomena that occurs the same way every
• Dennett rejects the idea of consciousness as a
• Consciousness does not occur in a single area; it
is an abstraction.
• The foundation of Dennett‟s theory is that the
brain cannot process all incoming sensory
• The fact that we experience consciousness as
being „on-line‟ is therefore an illusion.
• Consciousness results from the activation of
revised collections of sensory information called
• Conscious experience is an updating, constantly
revising process that takes into account sensory
information arriving at different times and in
• Dennett uses the analogy of an author constantly
redrafting and revising a manuscript.
• Multiple drafts of sensory information are
assembled at particular points in time to form
the basis of conscious experience.
“Information entering the nervous system is under
continuous „editorial revision‟…the Multiple
Drafts model avoids the mistake of supposing
that there must be a single narrative (the „final‟
or „publishable‟ draft, you might say) that is
• Although Dennett rejects the concept of a
single „theatre‟ of consciousness, it could
be argued that his multiple drafts simply
represent a larger collection of smaller
Shanon‟s Consciousness Theory
• Benny Shanon (1990; 1998) argues that
consciousness comprises three distinct
• Shanon‟s theory focuses on the phenomenology
of human consciousness.
• Argues that features that are specific to
phenomenal experience are of distinct functional
• Attempts to address issue of phenomenal
(1) Sensed Being
• Ability to distinguish between animate
and living and inanimate and dead.
• Sensed Being is a prerequisite of
2) Mental Awareness
• Self-awareness of the contents of
• This forms the core of conscious
• Awareness of mental computations (or
‘mentations’) that can be the subject of
• Reflection is derived from conscious
Meta-observation – reflection on the content
of mental states
Monitoring or Control – control process that
guides or governs thinking by checking
and evaluating thoughts.
• Very difficult to empirically test Shanon‟s
• Different components are vaguely defined
– theory offers a description of
consciousness rather than an explanation.
Important Issues in
• Can computers ever duplicate human
• Is consciousness really necessary in
Does the brain work like a
• Over the last 40 years cognitive psychology has
used microcomputers as an analogy for the
• General-purpose computers have three main
(1) Input and output devices that allow the user to
communicate with the computer.
(2) A memory system that permits the storage of
(3) A central processor that controls the major
functions of the computer.
• In principle a computer can be
programmed to duplicate the principle
cognitive functions of perception,
memory, and problem-solving.
• Such computer simulations include visual
pattern recognition, speech
comprehension, reading, movement
control, mental imagery, and memory.
• The construction of computer programs
that simulate human mental functions is
called artificial intelligence.
• Computer simulations require formal
modelling of cognitive functions.
• Establishing what steps are necessary for a
computer to simulate a cognitive ability
may give insight into the kinds of process
the brain must perform.
• Critics argue that computers may perform
tasks in an entirely different way to the
• Computer processing maps poorly onto
human performance of similar tasks.
• Majority of computers rely on serial
• In contrast the brain appears to utilise
• Strong A.I. position states that a computer
which exactly duplicates the functions of
the brain would by definition become
• Critics argue that true consciousness can
never be achieved by an artificial non-
Is Consciousness Really
• Being able to monitor and control our behaviour
are consequences of information being shared
across cognitive modules.
• These are functions of access consciousness.
• How important is phenomenal consciousness
for cognitive functioning?
• Philosophers use the concept of zombies.
• „Zombies‟ are hypothetical beings that possess
exactly the same cognitive processes as we do,
but without conscious experience.
• Conscious experience does not appear to be an
inevitable consequence of cognitive and neural
• The majority of cognitive models do not feature
a functional role for phenomenal consciousness.
• Some argue that phenomenal consciousness is
an epiphenomenon of neural and cognitive
processing (i.e., a by-product that plays no
functional role in the system).
• Cognitive models of consciousness share the
assumption that it is non-unitary in nature.
• Artificial Intelligence creates computer
programs that simulate human mental functions.
• Access consciousness is essential for normal
• Major issue in consciousness studies is what
function phenomenal consciousness may play
during human cognition.
• Make sure that you read the consciousness
chapter in Martin. Also read the „Drugs
and Behaviour‟ section in Chapter 4.
• Also consider looking at alternative
textbooks like Bernstein or Gleitman.
• Questions on this section of the course
will feature material from all six lectures.