
 
Unpleasant arising from perception of the 
unknown, as discussed in this paper, is one of the 
“pain of the heart.” 
3  STRUCTURE OF A MONAD 
A MoNAD is a conscious module developed by the 
authors. It is a computational model for studying 
consciousness using neural networks (NNs). 
A MoNAD consists of a cognition system (a), 
behavior system (b), primitive representation region 
(c), symbolic representation region (d) which is a 
common area shared by the cognition and behavior 
systems, and input/output units (S and M) as shown 
in Fig. 1. 
External information (S) enters the MoNAD at 
the input unit and normally goes through p1, 
cognition system (a), p5 and symbolic representation 
region (d). The symbolic representation region (d) 
represents the state of the self and the other as 
determined by the input information and language 
labels RL and BL. RL is a language label for 
information that is currently being cognized while 
BL is the label for the behavior that is to be 
performed next. RL is neuro-calculated from 
information S, cognition information BL one-step 
prior and behavior information M’ one-step prior. 
Information of the cognition representation RL is 
constantly being copied to the behavior 
representation BL in the absence of any other 
information input from the higher-level modules into 
BL. In the symbolic representation region, the state 
of the self and the other is labeled separately. At 
present, all neural networks used in the study are 
top-down networks, and supervised learning is used 
because the main topic of this present study is the 
function of human consciousness. 
The behavior command from BL basically passes 
through p6, behavior system (b), p2 and output unit 
M. M is the information output from the MoNAD. It 
is also transmitted to the lower-level MoNAD 
modules. Information M is neuro-calculated from 
information passing through BL and p6, input 
information S and behavior information M’ one-step 
prior. 
One of the features of our MoNAD is that the 
cognition system and behavior system share the 
primitive representation region (c). Thanks to this 
primitive representation region, the system learns 
behaviors when cognizing and learns cognition 
when behaving. The closed loop information circuit 
passing through the primitive representation region 
and symbolic representation region makes it possible 
for the MoNAD to generate artificial inner thoughts  
 
Figure 1: Structure of MoNAD. 
and expectations in the robot. Another feature of the 
MoNAD is that the state of the self is understood by 
somatic sensation M’. 
4 STRUCTURE OF THE 
CONSCIOUS SYSTEM 
The conscious system comprises three subsystems: 
reason, emotion-feelings and association. All 
subsystems have a similar MoNAD structure. The 
reason and emotion-feelings subsystems have a 
hierarchical structure formed of MoNADs. The 
reason subsystem uses input information to cognize 
the outer world and the state of the self, and outputs 
behavior from the output unit. The emotion-feelings 
subsystem employs information from the condition 
of the robot’s body and represents emotions and 
feelings. Two feeling MoNADs, one representing 
pleasant and one unpleasant, form the top layer of 
the emotion subsystem. Information from the reason 
subsystem (cognized representation) is also used in 
the final determination of a state of pleasant or 
unpleasant. 
The association subsystem uses information from 
the reason and emotion-feelings subsystems and 
integrates the representations of both subsystems. 
The association subsystem learns, by using the result 
of integration, and outputs a behavior capable of 
eventually realizing pleasant for the self from the 
reason subsystem. 
 
Figure 2: A Model of the Conscious System. 
A STUDY OF A CONSCIOUS ROBOT - An Attempt to Perceive the Unknown
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