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Mitsuo Kawato’s Examples 147
Figure 8.8. Bidirectionality theory and selfconsciousness (Kawato’s draw-
ing was simplified by the author for this description).
1996). Furthermore, he says, “The role of the forward and reverse
models of interaction between the modules is to set favorable initial
conditions for the relaxation algorithm by an intermediary of a
number of modules, and accelerate the relaxation algorithm for the
integration of the modules.” He explains, “When our consciousness
works normally, we feel the world’s only perception image and are
executing a consistent action plan.”
It is not difficult, according to Kawato, to model interactions
between modules. The problem is if the total memory of the
interaction models becomes equal to or exceeds that of the main
bidirectional modules, the merits of convergence and high-speed
processing are lost, and hence the interaction models must be poor.
“Forward models of interactions between modules can be regarded
June 25, 2012 12:37 PSP Book - 9in x 6in 08-Junichi-Takeno-c08
148 Machine Consciousness
as the approximate models of other areas of the brain,” Kawato says,
“Based on this hypothesis, we can say that consciousness is a process
of approximating the huge volume of parallel calculations that
occur subconsciously to resolve the ill-posedness of sensorimotor
integration with extremely simplified false serial calculations.” He
further argues, “Forward models of module integration, generally,
are similar to reverse models of the external world because they
convert sensory inputs into motor outputs. Likewise, reverse models
of module integration can be said to be forward models of the
external world. These computations circulating through the forward
and reverse models make it possible to emulate one’s own thoughts,
predict one’s own behavior and perform the act of introspection.”
Emulation here means to run part or the whole of a system
on other software or hardware that behaves like the original
system.
Kawato’s writing is not so easy to follow. I will interpret it as
I understand it, risking the claim of misunderstanding. Forward
models of interaction (Fig. 8.8a) are approximations of reverse
models (Fig. 8.8b) of sensorimotor bidirectionality modules, and
the reverse models (Fig. 8.6c) of interaction are approximations
of forward models (Fig. 8.8d) of the bidirectionality modules.
These approximate forward and reverse models are considered
to be situated above the real-world models (forward and reverse
models of the sensorimotor bidirectionality modules) and behave
as an emulator that approximates the real world as a two-tier
world. Kawato’s argument that computations circulating through
the approximate forward and reverse models, which are sparse
due to the two-tier structure, enable the “emulation of one’s own
thought,” “prediction of one’s own behavior,” and “introspection” is
understandable as an idea but lacks concreteness.
Kawato further discusses the flow of consciousness.
Each forward or reverse model of module interactions comprises
three parts: interface to the sensory module presumably located
in the prefrontal area, interface to the motor area assumed to be
partly located in the basal ganglion, and the model itself which is
said to reside on the outside of the cerebellar hemisphere, and is
divided into several micro-zones as shown with the vertical lines
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Mitsuo Kawato’s Examples 149
in the figure. This means that consciousness has just one stream
but the direction of the stream of consciousness is controllable.
When driving a car, for example, you can converse with passengers,
listen to music or concentrate on driving. This is because although
the interface to the sensory and motor modules is just one
route, several models are prepared to cope with certain possible
combinations of modules (Kawato, 1996).
Kawato’s description lacks clarity, but he seems to mean that
the flow of consciousness (the reason why “a driver is capable of
conversing with passengers”) is related to the micro-zones located
in the interaction modules.
8.4.1 Summary and Observations
Kawato studies the integration of the human sensory and motor
systems. He needs to solve the long-standing “binding problem” that
has been annoying brain researchers. To solve this problem, Kawato
proposes the bidirectionality model for sensorimotor integration.
According to Kawato, the proposed method is capable of suppressing
a combinatorial explosion and other problems compared with
conventional solutions. He further proposes the idea of module
interaction models as a higher level of a bidirectionality model
to accelerate the processing speed of various modules in the
bidirectionality model. His interaction models are approximations of
the already-mentioned bidirectionality models. He explains that the
interaction models can approximately reproduce the functions of the
bidirectionality models He explains that the “emulation of one’s own
thought,” “prediction of one’s own behavior,” and “introspection” are
enabled because the interaction models approximately reproduce
the bidirectionality models. He further says that self-consciousness
may be explained in like manner.
According to Kawato, consciousness is a process of approxi-
mating the huge volume of parallel calculations of sensorimotor
integration that occur subconsciously with simplified false serial
calculations. He says that the flow of consciousness is related to the
microzones of the interaction models.
The author acknowledges the value of Kawato’s bold hypothesis
introducing bidirectionality models to explain consciousness but at
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150 Machine Consciousness
the same time cannot see any concrete explanations. Kawato seems
to have not yet formed a consistent theory about the function of
human consciousness.
8.5 Cynthia Lynn Breazeal’s Kismet
Cynthia Lynn Breazeal developed, in cooperation with Brooks, a
robot named Kismet, which is capable of interacting with humans
in real time. The humanoid head robot can move its eyes, eyebrows,
mouth, and neck (Fig. 8.9), and it listens and talks. This sociable
robot understands feelings using information from differences in
height, pitch, etc., and expresses its feelings vocally. Its facial
expressions also show feelings. The drive mechanism makes use of
the psychological knowledge of the Theory of Mind. An outline of the
circuit developed on the basis of this theory is shown in Fig. 8.10.
With these circuits, the robot reacts by driving motors in
response to the stimuli given to the system via sensor inputs. Various
Figure 8.9. Head robot Kismet.
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Cynthia Lynn Breazeal’s Kismet 151
Figure 8.10. Outline of Kismet’s drive system.
subsystems are layered and implement their respective functions.
As the essential part of the system, the information obtained by
the sensors is subject to the extraction of low-level features. On the
basis of the resultant information, the high-level cognition system
is activated by the Caution system, that is, the cognition process
is a two-stage process. There are two closed loops for processing
information internally. In one circuit, information circulates through
the Caution, High-Level Cognition, and Behavior systems. In the
other circuit, information runs through the Motivation, Behavior,
and High-Level Cognition systems. In the former circuit, if any
information has a feature to note, the robot turns to the object or the
vision cameras are rotated by drive motors while using the Behavior
system as if a human were looking at an object and watching it
intently. This is intended to achieve a higher-level cognition. In
the latter circuit, the robot’s attention is given to already-learned
information such as color and shape, to achieve high-level cognition.
The two circuits each have their own roles. The Motivation system is
the highest-level layer in this system.
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