In this article, I propose a working hypothesis that the nervous system of pain sensation is a key component to shape robots' (arti cial systems') conscious minds through the developmental process of empathy, morality, and ethics based on the MNS that promotes the emergence of concept of self (and others). First, the limitation of the current progress of AI focusing on deep learning is pointed out from a viewpoint of the emergence of consciousness. Next, the outline of ideological background on issues of mind in a broad sense is shown. Then, cognitive developmental robotics (CDR) is introduced with two important concepts; physical embodiment and social interaction both of which help to shape conscious minds. Following the working hypothesis, existing studies of CDR are brie y introduced and missing issues are indicated. Finally, an issue how robots (arti cial systems) could be moral and legal agents is shown.
The rapid progress of observation and measurement technologies in
neuroscience and physiology have revealed various kinds of brain activities, and the
recent progress of AI technologies represented by deep learning (DL) methods is
remarkable. Therefore, it appears no wonder that arti cial consciousness can be
realized soon. However, due to the fundamental limitations of the deep learning,
it seems difficult. The main reason is that the current DL emphasizes the
perception link between the sensory data and labels, lacking strong connection with
the motor system, therefore, it does not seem to involve physical embodiment
and social interaction both of which develop a rich loop including perception
and action with attention, cognition, and prediction (Fig. 1). This is essential
for consciousness research including unconsciousness.
Cognitive developmental robotics [
With regard to the relationship between the mind and body or things, it is Descartes who advocated mind and body dualism and laid the foundation of modern philosophy. It is Husserl who insisted on \New Cartesianism" that goes beyond Descartes to transcendental phenomenology and gave phenomenological consideration. He developed a way of thinking of subjectivity between subjective and objective intervals, and gave great in uence to the next generations after him. He predicted that the analysis of nature is based on individual conscious experience. Heidegger and Merleau-Ponty have extended and evolved Husserl's phenomenological theory.
Heidega argues that \being-in-the-world" is born by dynamic interaction between the future possibilities of individual agents and their past possibilities without separating subjectivity and objectivity. He also pointed out the importance of some kind of social interaction that individuals can exist mutually under the prior understanding of how each individual interacts with purpose.
Merleau-Ponty argues that in addition to subjectivity and objectivity, the dimension of \physical embodiment" emerges, where the body of the same thickness is given to objects that are touched or viewed at the same time as the subject touching and seeing, and that the body could be a place where exchanges between two poles of subjective and objective is repeated. In other words, he pointed out the importance of the body as a media connecting an objective physical world and a subjective experience. As mentioned above, this is the basic concept of \physical embodiment" in the cognitive development robotics.
Based on these ideological backgrounds, CDR has done several studies, where computational models were proposed to reproduce the cognitive developmental processes by utilizing computer simulations and real robot experiments. Although CDR has not mentioned about consciousness explicitly, here we argue any possibility of arti cial consciousness more explicitly by proposing a working hypothesis based on the nervous system of pain sensation. The story is as follows: 1. Embedding pain nervous system into robots for them to feel pain. 2. Through MNS (Mirror Neuron System) development, robots may feel pain in others. 3. That is, emotional contagion, emotional empathy, cognitive empathy, and sympathy/compassion develop inside robots. 4. Proto-morality emerge. 5. Robots could be agents who could be moral being, and at the same time, subjects to moral consideration. 6. Legal system for robots and AI will be considered.
The rest of the paper is organized as follows. First, the nervous system for pain sensation is brie y explained from a neuroscienti c viewpoint. Next, a preliminary experiment of soft tactile sensor is shown as a potential of arti cial nociceptor system. Then, we argue any possibility of arti cial empathy, morality, and ethics in CDR by integrating existing studies and future issues. The above story can be regraded as a developmental process of arti cial consciousness. 2
The perception of injurious stimuli, called nociception, or pain has its own
nervous pathways different from mechanosensory pathways (see Chapter 10 in [
As a preliminary step of arti cial pain nervous system, we developed a soft tactile
sensor [
Based on the capability of discrimination of the tactile sensor, arti cial nervous system for pain sensation can be embedded into the robot body and brain in parallel with normal mechanoreceptor pathway with a mechanism of pain regulation (the gate theory). 3.2
Arti cial empathy
The feeling that this pain is shared is thought to be the source of empathy
assuming that the mirror neuron system enables agents to percieve others' pain
1. Actually, a survey article of arti cial empathy [
Dynamic coupling between body and brain with neural oscillator
networks Park et al. [
[Hori et al., 2007]
[Watanabe et al., 2007]
subnetworks loosely connected each other and corresponds to a stable motion
while the latter mainly consists of one big subnetowork strongly connected with
sensory-motor nuerons and corresponds to an unstabel motion that connects the
stable motions. The left-bottom of Fig. 5 indicates the summary of this work,
and the following two points are essential for the main topic of the paper.
1. Two kinds of motions and network structures behind may correspond to very
primitive lelvels of unconscious (stable motion) and conscious (unstable
motion) states, respectively. More plausibly, stable motions could be attractors
and unstable motions appear to transit between the attractors in the phase
space.
2. The separation of two kinds subnetworks can be regarded as functional
differentiation that is a basic mechanism for the emergence of new functions
[
Emergence of mirror neuron system and emotion sharing Nagai et al. [
Such mirroring could be expanded from action to emotions, that is, emotion
sharing. Watanabe et al. [
Sharing painful situations induces sympathetic behavior In case of the emotion sharing of pain, the system needs to transmit two kinds of information, the sensory discrimination of pain (location, intensity, and quality), and the affective and motivational responses to pain as described in 2. The former information comes from the sensor system of the body while the second one comes from its own experiences of pain. The ideal story is as follows: 1. The information for sensory discrimination of pain (location, intensity, and quality) is transmitted to CNS from the sensory system. 2. If the above experience is the rst time, the related information such as cause and/or reason is also transmitted with the information above. 3. Else, the memory of this experience is enhanced in the memory storage. 4. When the painful situation of others is observed, emotion sharing of pain happens, and also the memory of the similar experience is recalled. 5. Take actions to reduce the pain of others based on the recalled experience. A robot could be a moral agent if it can generate such behavior successfully. At the same time, such a robot may have a right to receive moral behavior from others. Such a moral agency could be a solution to the rst law of three laws of robotics 2. That is, \A robot may not injure a human being or, through inaction, allow a human being to come to harm." 4
To challenge the hard issue of consciousness, I attempted to represent it as a
phenomena of the developmental process of arti cial empathy for pain and moral
behavior generation. The conceptual model for the former is given by [
Before these issues, there are so many technical issues. Among them, the followings should be intensively addressed. 2 https://en.wikipedia.org/wiki/Three Laws of Robotics
This research was supported by JST Strategic Basic Research Programs (RISTEX), Research Area \Human-Information Technology Ecosystem," entitled \Legal Beings: Electronic personhoods of arti cial intelligence and robots in NAJIMI society, based on a reconsideration of the concept of autonomy"(Oct. 2017 Sep. 2020)