NEWSLETTER-Feb2001

Introduction
It is a common insult in Japan to hear someone ridiculed as "one-cellular," indicating minimal mental capacity on the part of the subject of the remark. But this put-down may lose some of its bite in the future, because our research has demonstrated that the true slime mold, a giant unicellular organism with multiple nuclei, is able to solve a maze and other combinatorial optimization problems. I would like to introduce some of the background of our findings in this article.

Can an Ameboid Organism Solve a Maze?

The plasmodium, a true slime mold, is an aggregate of viscous materials called protoplasm. The yellow object in Fig. 1 is an individual plasmodium. While it lacks a nervous system, legs or eyes, the plasmodium is still able to move its mass to wherever it finds food. The mere oddities of this strange-looking animal have provided sufficient material for several research papers, even without my having gained any special insights into its behavior, so we have continued to observe it closely. It was about four years ago, as I merely cultivated and observed the plasmodium, that the unexpected and surprising cleverness that it displayed gave me the idea of publishing what we had learned.

However, it was just this year that we have been able to experimentally demonstrate the plasmodiumÕs ability to solve a maze. Our paper on the subject was published in NATURE magazine and we received much media attention, such as from the Washington Post and the BBC. I was very excited by all the attention, and determined to accept as many interview requests as possible, because this has never happened to me before, and may never again. At this point IÕd like to mention the outstanding support we have received from the RIKEN Public Relations office, and especially the exceptional cooperation and guidance we received from Ms. Nio, who had charge of our project. Without such able assistance regarding the details of the issuance of press releases and the holding of press conferences, etc., there is no doubt that we should not have had such a fruitful response from the press. The following is an example, a press release from NATURE magazine:

"The reputation of the amoebae as less than intelligent members of the animal kingdom may be undeserved. In a Brief Communication this week, Toshiyuki Nakagaki of the Bio-Mimetic Control Research Center, Nagoya, Japan, and colleagues show that a single-celled organism can negotiate the shortest way out of a maze (Fig. 2). Pieces of the slime mold Physarum polycephalum placed in a 3-centimeter-square maze join up and expand to fill all available space. But when two pieces of food are placed at separate exit points in the labyrinth, the organism withdraws itself from dead ends until its entire 'body' runs between the two nutrients along the shortest possible route. Effectively, it solves the puzzle. 'This remarkable process of cellular computation implies that cellular materials can show a primitive intelligence,' the researchers say." (Vol. 407, P470, Sep. 2000)

Is the slime mold intelligent?
This seems purely a matter of definition. The term "intelligent material" is one often seen in scientific journals; if this is indeed a valid concept, then the term is likely applicable to the true slime mold. In this regard, I have, in the course of my press interviews about this subject, found myself discussing with foreign reporters just what intelligence is. Whereas Japanese reporters were most deeply concerned with the details of just how such an organism was able to solve a maze, those from overseas tended to focus on whether or not the phenomenon represented intelligence. In order to avoid this quagmire, Dr. Agota, the Hungarian coauthor of the paper published in Nature, even proposed prior to publication that we delete terms related to intelligence from our draft, and one of the referees as well indicated his doubt that the organism could be considered intelligent. I got the feeling that some Western people, possibly because of the influence of Christianity, may feel somewhat uncomfortable when faced with the possibility of intelligence other than human. Then again, the meaning of the word "intelligence" in English and that of its Japanese equivalent, "chi-sei," may be totally different to begin with. But even having said that, I believe that the interpretation of the word has little bearing on the day to day direction of research for those of us involved in work such as this, bordering on both biology and physics. The focus of research, as well as that of the materials published on that research, are largely determined by the viewpoint held by the researcher. IÕd like to discuss this point further.

Between Biological and Physical Phenomena
First, let us suppose that all biological phenomena are physical phenomena. In biology, these purely physical phenomena are often labeled "functions," and their biological significance debated. However, function seems to be a concept that comes about only when a purpose has been ascribed to a specific physical phenomenon. If a physical phenomenon appears and contributes to the accomplishment of a purpose, that phenomenon is considered functional. As the highest purpose of a living thing is survival and the continuation of the species, a living organism can be considered in and of itself to constitute a survival mechanism. There are undoubtedly large numbers of physical phenomena which have not survived over the hundreds of millions of years of earthÕs history, and those we see around us today represent only the survivors. Clearly, there must be reasons for these systems having survived over all that time, and I believe that the study of these survival mechanisms is a central issue to the science of biology. Thus, when studying the physical phenomena seen in living organisms, it is necessary to study them as survival mechanisms. To put it another way, the physical phenomenon must be studied in terms of how it contributes to the survival of the organism, as it is this contribution that attributes functionality to the phenomenon. Yet it is important to remember that such phenomena were not originally designed by the organism as survival mechanisms, and that there are major differences between the way humans design things and how they come about as a result of natural influences. It is these differences that biologists study.

The term "information" is often used in biology. While Shannon (C. E. Shannon, The mathematical theory of communication, Bell Syst., Tech. Journ.) has provided a definition for this term, in biology the meaning, or the role of the information, is most important. One measure for determining the meaning of information, or the role it plays, is to gauge the significance it possesses in terms of the organismÕs ability to survive. This semantic process is how the organism interprets the information. As a part of this process, numerical symbols, for instance, may be interpreted as a function of their shape, or even by their sequence or order, but a shorthand way of describing this process might be to use the word "computation." The solution to the problem (i.e., the organism as it currently exists) is obtained through computation (which evolves according to the principles of physical dynamics).

Can something with no consciousness be considered intelligent?
It seems as though more care should be exercised in the use of the term. In order to put this discussion into a more logical context, we need to define what is meant by the use of the term "ntelligence,"which I will attempt to do here: Humans have consciousness, i.e., we are aware of ourselves. This is generally what we call "ind,"that part of each of us which is aware that, for instance, " am looking at something green,"or that remembers " rode a bicycle yesterday."The mind is reflexive: it is able to view itself objectively. It can view itself apart from the rest of the world as an abstract model, maybe even allowing it to come to a better self-understanding. One would likely be hard put to explain how one felt when looking at something green; and even if the person were aware of the origination of that particular feeling, it would not be possible to have another person step together with them into that individual realm of feeling to gain the same impression. Thus the world in which each of us resides may not necessarily coincide with those of others; rather our own, individual worlds are realms created in our own minds, identical with our individual identity, or self consciousness. Thus, the world we exist in is not something outside of us; rather, each of us exists entirely alone in our own, separate worlds.

Next let's consider the unconscious realm, a world which has a great deal of influence on the consciousness. We have only to consider our own internal information processing mechanisms to understand that most of them take place on an unconscious level. I doubt anyone could explain how it is their body maintains balance when they ride a bicycle. While weÕre riding, our body just naturally performs the calculations required to solve the equation. It would be quite difficult for us to clearly define these on the conscious level, and were one able to do so and publish the method employed, it would undoubtedly be an important contribution to the scientific literature (like the very interesting article that appeared in Nature magazine just a few years back on how a baseball outfielder is able to get under a fly ball to catch it). I believe that such unconscious information processing mechanisms exist, to a greater or lesser extent, in all living things (for instance, the grouping tendencies of ants, or paramecium). Is this kind of information processing to be considered intelligence? On the other hand, are people with no conscious awareness of themselves, such as one in a coma, or merely asleep, to be considered unintelligent? If we can answer these questions, then we should be able to answer the question as to whether or not single-celled animals possess intelligence. It is my goal to research and clarify these unconscious information processing mechanisms, if possible at the material level. In this effort, I consider the slime mold to be a most important, perhaps even ideal, subject.

Acknowledgements: RIKEN, Frontier and I
After three years with the RIKEN Frontier Bio-Mimetic Control Research Center in Nagoya, I this year became a member of the Spatio-Temporal Function Materials Research Group at the Wako Campus. It was during this period that I conducted my research on the slime mold, and I would like to take this opportunity to express my gratitude to the three people in these places that made it possible for me to engage in this project: Dr. Masahiko Hara, team leader of the Local Spatio-Temporal Function Materials Laboratory, Dr. Shigeyuki Hosoe, team leader of the Laboratory for Bio-Mimetic Control Systems, and Dr. Ito Masami, the late director of the RIKEN Bio-Mimetic Control Research Center and team leader of the Laboratory for Bio-Mimetic Control Systems. My special thanks goes to Dr. Ito, who not only suggested that Dr. Hiroyasu Yamada and I team up as coauthors for the study, but who was also instrumental in providing helpful criticism and encouragement even when research results were not forthcoming, and without whom this project would never have seen the light of day. My only regret is that I am unable to show Dr. Ito the results of the research project in which he played so important a part.

Highlights:
›Ameboid Organisms May be More Clever than We'd Thought! Dr.Toshiyuki Nakagaki Local Spatio-Temporal Functions Laboratory Introduction It is a common insult in Japan to hear someone ridiculed as "one-cellular," indicating minimal mental capacity on the part of the subject of the remark. But this put-down may lose some of its bite in the future, because our research has demonstrated that the true slime mold, a giant unicellular organism with multiple nuclei, is able to solve a maze and other combinatorial optimization problems. I would like to introduce some of the background of our findings in this article. Can an Ameboid Organism Solve a Maze? The plasmodium, a true slime mold, is an aggregate of viscous materials called protoplasm. The yellow object in Fig. 1 is an individual plasmodium. While it lacks a nervous system, legs or eyes, the plasmodium is still able to move its mass to wherever it finds food. The mere oddities of this strange-looking animal have provided sufficient material for several research papers, even without my having gained any special insights into its behavior, so we have continued to observe it closely. It was about four years ago, as I merely cultivated and observed the plasmodium, that the unexpected and surprising cleverness that it displayed gave me the idea of publishing what we had learned. However, it was just this year that we have been able to experimentally demonstrate the plasmodiumÕs ability to solve a maze. Our paper on the subject was published in NATURE magazine and we received much media attention, such as from the Washington Post and the BBC. I was very excited by all the attention, and determined to accept as many interview requests as possible, because this has never happened to me before, and may never again. At this point IÕd like to mention the outstanding support we have received from the RIKEN Public Relations office, and especially the exceptional cooperation and guidance we received from Ms. Nio, who had charge of our project. Without such able assistance regarding the details of the issuance of press releases and the holding of press conferences, etc., there is no doubt that we should not have had such a fruitful response from the press. The following is an example, a press release from NATURE magazine: "The reputation of the amoebae as less than intelligent members of the animal kingdom may be undeserved. In a Brief Communication this week, Toshiyuki Nakagaki of the Bio-Mimetic Control Research Center, Nagoya, Japan, and colleagues show that a single-celled organism can negotiate the shortest way out of a maze (Fig. 2). Pieces of the slime mold Physarum polycephalum placed in a 3-centimeter-square maze join up and expand to fill all available space. But when two pieces of food are placed at separate exit points in the labyrinth, the organism withdraws itself from dead ends until its entire 'body' runs between the two nutrients along the shortest possible route. Effectively, it solves the puzzle. 'This remarkable process of cellular computation implies that cellular materials can show a primitive intelligence,' the researchers say." (Vol. 407, P470, Sep. 2000) Is the slime mold intelligent? This seems purely a matter of definition. The term "intelligent material" is one often seen in scientific journals; if this is indeed a valid concept, then the term is likely applicable to the true slime mold. In this regard, I have, in the course of my press interviews about this subject, found myself discussing with foreign reporters just what intelligence is. Whereas Japanese reporters were most deeply concerned with the details of just how such an organism was able to solve a maze, those from overseas tended to focus on whether or not the phenomenon represented intelligence. In order to avoid this quagmire, Dr. Agota, the Hungarian coauthor of the paper published in Nature, even proposed prior to publication that we delete terms related to intelligence from our draft, and one of the referees as well indicated his doubt that the organism could be considered intelligent. I got the feeling that some Western people, possibly because of the influence of Christianity, may feel somewhat uncomfortable when faced with the possibility of intelligence other than human. Then again, the meaning of the word "intelligence" in English and that of its Japanese equivalent, "chi-sei," may be totally different to begin with. But even having said that, I believe that the interpretation of the word has little bearing on the day to day direction of research for those of us involved in work such as this, bordering on both biology and physics. The focus of research, as well as that of the materials published on that research, are largely determined by the viewpoint held by the researcher. IÕd like to discuss this point further. Between Biological and Physical Phenomena First, let us suppose that all biological phenomena are physical phenomena. In biology, these purely physical phenomena are often labeled "functions," and their biological significance debated. However, function seems to be a concept that comes about only when a purpose has been ascribed to a specific physical phenomenon. If a physical phenomenon appears and contributes to the accomplishment of a purpose, that phenomenon is considered functional. As the highest purpose of a living thing is survival and the continuation of the species, a living organism can be considered in and of itself to constitute a survival mechanism. There are undoubtedly large numbers of physical phenomena which have not survived over the hundreds of millions of years of earthÕs history, and those we see around us today represent only the survivors. Clearly, there must be reasons for these systems having survived over all that time, and I believe that the study of these survival mechanisms is a central issue to the science of biology. Thus, when studying the physical phenomena seen in living organisms, it is necessary to study them as survival mechanisms. To put it another way, the physical phenomenon must be studied in terms of how it contributes to the survival of the organism, as it is this contribution that attributes functionality to the phenomenon. Yet it is important to remember that such phenomena were not originally designed by the organism as survival mechanisms, and that there are major differences between the way humans design things and how they come about as a result of natural influences. It is these differences that biologists study. The term "information" is often used in biology. While Shannon (C. E. Shannon, The mathematical theory of communication, Bell Syst., Tech. Journ.) has provided a definition for this term, in biology the meaning, or the role of the information, is most important. One measure for determining the meaning of information, or the role it plays, is to gauge the significance it possesses in terms of the organismÕs ability to survive. This semantic process is how the organism interprets the information. As a part of this process, numerical symbols, for instance, may be interpreted as a function of their shape, or even by their sequence or order, but a shorthand way of describing this process might be to use the word "computation." The solution to the problem (i.e., the organism as it currently exists) is obtained through computation (which evolves according to the principles of physical dynamics). Can something with no consciousness be considered intelligent? It seems as though more care should be exercised in the use of the term. In order to put this discussion into a more logical context, we need to define what is meant by the use of the term "ntelligence,"which I will attempt to do here: Humans have consciousness, i.e., we are aware of ourselves. This is generally what we call "ind,"that part of each of us which is aware that, for instance, " am looking at something green,"or that remembers " rode a bicycle yesterday."The mind is reflexive: it is able to view itself objectively. It can view itself apart from the rest of the world as an abstract model, maybe even allowing it to come to a better self-understanding. One would likely be hard put to explain how one felt when looking at something green; and even if the person were aware of the origination of that particular feeling, it would not be possible to have another person step together with them into that individual realm of feeling to gain the same impression. Thus the world in which each of us resides may not necessarily coincide with those of others; rather our own, individual worlds are realms created in our own minds, identical with our individual identity, or self consciousness. Thus, the world we exist in is not something outside of us; rather, each of us exists entirely alone in our own, separate worlds. Next let's consider the unconscious realm, a world which has a great deal of influence on the consciousness. We have only to consider our own internal information processing mechanisms to understand that most of them take place on an unconscious level. I doubt anyone could explain how it is their body maintains balance when they ride a bicycle. While weÕre riding, our body just naturally performs the calculations required to solve the equation. It would be quite difficult for us to clearly define these on the conscious level, and were one able to do so and publish the method employed, it would undoubtedly be an important contribution to the scientific literature (like the very interesting article that appeared in Nature magazine just a few years back on how a baseball outfielder is able to get under a fly ball to catch it). I believe that such unconscious information processing mechanisms exist, to a greater or lesser extent, in all living things (for instance, the grouping tendencies of ants, or paramecium). Is this kind of information processing to be considered intelligence? On the other hand, are people with no conscious awareness of themselves, such as one in a coma, or merely asleep, to be considered unintelligent? If we can answer these questions, then we should be able to answer the question as to whether or not single-celled animals possess intelligence. It is my goal to research and clarify these unconscious information processing mechanisms, if possible at the material level. In this effort, I consider the slime mold to be a most important, perhaps even ideal, subject. Acknowledgements: RIKEN, Frontier and I After three years with the RIKEN Frontier Bio-Mimetic Control Research Center in Nagoya, I this year became a member of the Spatio-Temporal Function Materials Research Group at the Wako Campus. It was during this period that I conducted my research on the slime mold, and I would like to take this opportunity to express my gratitude to the three people in these places that made it possible for me to engage in this project: Dr. Masahiko Hara, team leader of the Local Spatio-Temporal Function Materials Laboratory, Dr. Shigeyuki Hosoe, team leader of the Laboratory for Bio-Mimetic Control Systems, and Dr. Ito Masami, the late director of the RIKEN Bio-Mimetic Control Research Center and team leader of the Laboratory for Bio-Mimetic Control Systems. My special thanks goes to Dr. Ito, who not only suggested that Dr. Hiroyasu Yamada and I team up as coauthors for the study, but who was also instrumental in providing helpful criticism and encouragement even when research results were not forthcoming, and without whom this project would never have seen the light of day. My only regret is that I am unable to show Dr. Ito the results of the research project in which he played so important a part.