THYMOS
A newsletter of research on Consciousness, Mind and Life

by piero scaruffi

Researchers are welcome to submit news and articles about breakthroughs and events in the areas of cognitive science, artificial intelligence, neurobiology, artificial life, linguistics, neural networks, connectionism, cognitive psychology, mind, philosophy, psychology, consciousness. Email the editor at this Email address. Readers who would like to receive periodic news and updates on cognitive science, philosophy of mind, neurobiology, artificial intelligence, etc, are invited to register to my mailing list.

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November 2002
  • Joelle Bernier, a researcher from Quebec (Canada), has conducted experiments that show how neurons are created in adult brains. Until a few years ago, neurons were thought to be created only at childhood. Then we observed neurons being created in a part of the brain. Bernier's experiments show neurons being created in the amygdala of the adult brain. The amygdala is an important center for processing emotions, and in particular "fear".
August 2002
  • Research on the origin and maintenance of biological diversity has led biologists to discover that diversity of animal species and diversity of human languages go hand in hand, i.e.: cultural and biological diversity are lowest and highest in the same places. In other words, areas with the most animal species also contain the greatest number of human languages.
    Danish biologist Carsten Rahbek , in collaboration with British biologists Andrew Balmford and Joslin Moore of Cambridge University, has created a database on the distribution of all African mammals, birds, snakes and amphibians, that lists about 4,000 species. By using this database, he can study patterns of species distribution and their relationship with human activity. It turns out that areas inhabited by many animal species are also the areas where humans speak many languages, and viceversa.
    Of course, the relationship could be a mere coincidence. Other factors influence biological diversity (i.e., the weather) and perhaps the same factors end up influencing language diversity.
  • The Australian chemist Edith Sevick has conducted experiments that show it is possible to break the second law of thermodynamics at the level of atoms and molecules.
    The second law of thermodynamics is the one that introduced the popular concept of entropy: entropy can never decrease in a closed system. In other words, if the system is closed (i.e., it is not being operated upon by another system), it drifts towards absolute chaos and no information. A very good example of this law is that your house needs maintenance: problems don't fix themselves, you have to fix them. A system spontaneously loses "order" and "information", whereas order and information can be increased only by an external force. An alternative way of expressing this concept is that some energy is always lost when converting from one type of energy to another, i.e. whenever the system "does" something.
    The British physicist James Clerk Maxwell (famous for having unified electricity and magnetism and opened the way for Einstein's special theory of relativity) had already noted more than a century ago that the second law of thermodynamics is a "statistical" truth, not a mathematical one. A system is made of many particles. Properties due to the ensemble of particles are "statistical" because they simply express the fact that a "majority" of particles exhibit those properties (not necessarily every single particle does). Therefore the second law of thermodynamics does not completely rule out the possibility of decreasing entropy.
    What Denis Evans and Sevick has shown is that the second law of thermodynamics is continually being violated at the level of microscopic particles (albeit only for very short periods of time), although if you consider the whole system the second law of thermodynamics is always confirmed (see her paper).
    Sevick's study could eventually introduce a new fundamental property of nature, and a new fundamental limit. What her experiment shows is that, at some very small scale, machines would stop working the way they work at the scale we are used to. Thus, there would be a natural limit to miniaturization (machines would literally start working backwards if you make them "too small"). And this would, obviously, have an impact on things such as computers.
June 2002
  • In the quest for an explanation of dark matter and dark energy, the American physicist Paul Steinhardt and the British physicist Neil Turok have proposed the Cyclic Universe Theory, according to which there is no "big bang" to begin with, and there will be no "big crunch" to end with. Space and time existed ever since and will exist forever. There is no beginning or end. The evolution of the universe is due to a series of "bangs" (explosive expansions) and "crunches" (contractions). The big bang that we observe today with the most powerful detectors of microwaves is simply one of the many expansions following one of the many contractions. Each phase may last a trillion years, and therefore be undetected by human instruments. The cyclic nature of the universe would be due to "negative potential energy", a concept arising from string theory, rather than General Relativity's spatial curvature. In principle, this is the same idea advanced by the QSSC (Quasi Steady State Cosmology) of British physicist Geoffrey Burbidge and his collaborators Fred Hoyle and Jayant Narlikar. In fact, it is more orthodox than it may sound. Totally lacking is Burbidge criticism of black holes, quasars and the cosmic radiation.
  • The American neurologist Bradley Schlaggar has been studying the different use of the brain by children and adults. His theory is that the very same tasks are performed by children and adults using different brain regions. As the human brain matures, some functions are offloaded to other regions. Why this is happening and when it stops happening is the mystery that Schlaggar is trying to solve. It could be that some connections among brain regions are not mature enough in the early years of life. But why some regions would be better than others for performing some functions is still not clear. What is clear is that, as we grow up, we change the way we use our own brain.
May 2002
  • "Ecological population genetics" is the study of why and how living beings are the way they are within the environment that they inhabit. Insect colonies (and particularly ant colonies) are a favorite subject to study because they tend to have the most complex social organization. They are typically divided into different castes with different functions. For a long time there has been a debate on how such castes arise. One theory is that they are determined by the environment: there is nothing at birth to differentiate a worker from a warrior, just like there is nothing genetically different between a human being who works in a factory and a human being who fights in a war. In this sense, society is basically "forced" upon the colony: environmental pressures force living beings to get organized in societies. Instead, Stanford Univ's biologists Deborah Gordon and Veronica Volny have recently shown that there is a genetic determination of who does what. While studying the caste system of the red harvester ant, they found out that a queen mates with different males and the offspring belongs to a caste or another depending on the male. The castes are a product of the sexual behavior of the queen.
April 2002
  • German anthropologist Svante Paabo has found the first evidence of what causes the differences in behavior between chimpanzees and humans (who share 99% of their genes). In 1997 Paabo showed that the Neandertal man's DNA sequence falls outside the normal variation of modern humans. In other words, Neandertals were not our ancestors. Using a similar technique, biologists can show that the genes of chimpanzees and humans are mostly identical. It is a mystery why humans behave in such a different way. Their brains are amazingly similar. Proving that "pattern" and not "topology" determines what goes on inside the brain, Paabo's studies show that gene activity (i.e., production of protein) in the cerebral cortex of humans is five times more intense than in chimps. Human brains simply evolved five times faster than chimpanzee brains.
  • Christof Koch and his team have been investigating the portion of the brain in charge of visual processing. The idea is that visual processing is a function that generates consciousness of something out of integrating so many different inputs, and therefore is a good indication of how consciousness works. Koch is looking for the "neural correlates" of conscious experience, i.e. the neural activity related to the creation of a conscious experience. Koch's articles basically detail his quest for the area in the brain where consciousness arises (see for example, this article) The problem is that every year there seems a new area that is also involved...
March 2002
  • The South-African anthropologist Christopher Henshilwood has moved back the birthdate of thinking by about 40,000 years. Humans have existed for a very long time, but there is scant evidence that they were "thinking" until very recently. The cave paintings have been the strongest evidence yet for some kind of symbolic thinking (I paint something that refers to something else). In a Southafrican cave, Henshilwood discovered two pieces of ochre with geometric patterns, which could be symbolic artwork that would predate the oldest known cave paintings by more than 40,000 years. Some anthropologists and psychologists argue that the faculty of thinking developed suddenly, in a relatively short and intense burst of creativity, whereas others think that it developed gradually and slowly over many thousand years. If you believe that our evolutionary history parallels our developmental story (i.e., how we turn from children to adults) you tend to side with the former theory. If you believe that thinking followed the general patterns of anatomical evolution, you may side with the latter theory. The further back art objects go, the higher it is that the latter theory is right. An article on this finding
  • In the 1950s, the Russian psycho-physicist Yarbus realized that human beings do not scan a scene in a raster-like fashion. On the contrary, we jump from one point to the next one, in an apparently random manner. We only fixated for a very short period on each point. A "saccade" is a rapid eye movement that occurs while we are awake. Saccades occur several times a second. Basically, our eyes continuously scan the environment. In order to do this, our eyes need to continuously "refocus". "Saccadic eye movements" are opposed to the "pursuit eye movements", the slow, smooth eye movements that follow a steadily moving target. Saccadic eye movements are interesting because it may tell us a lot about how our brain works and, in particular, about the other "rapid eye movement", the one that occurs while we are sleeping (see this introduction to eye movements, see this introduction to saccadic movements, see this seminar, and, for example, this paper). The mystery, of course, is how can we perceive a stable world when our eyes are continuously changing target (a phenomenon known as "visual stability"). We should be perceiving a rather messy and frantic world. The German neurologist Alex Thiele is studying neuronal activity related to saccadic eye movement. His findings prove that the brain regulates the saccadic eye movement and "suppresses" some of the information in order to present a world as stable as possible.
    Saccades have been found to be shortcuts to relevant information in the environment. Since we cannot store the entire world in our brain, we simply store pointers to what is truly important in the environment. When we need to retrieve information, we use saccades. Basically, we retrieve information as we need it, instead of storing it permanently in our brain. Yarbus already knew that, while apparently random, the pattern of saccadic eye movements depends on the cognitive task to be performed (on what information we need to retrieve).
    For example, when we need to identify someone, the saccadic eye movements focus mostly on the eyes and the mouth. These are the regions that we mostly rely on for face recognition. Saccadic eye movement is not a random sampling of the environment, but a highly specific indexing of relevant information in the environment.
February 2002
  • The American neuroscientist Matthew Wilson from the Centre for Learning and Memory at the MIT is studying the way experience is represented and stored in the brain of rats. The idea is that one can examine the patterns of neural activity in the brain and relate those patterns to something that happened to the individual (rat) and that is being processed in the brain. The same studies can be applied to dreams. Dreams are widely believed to be a means to consolidate memories acquired during the day, by playing them against the genetic repertory and moving them from short-term memory to long-term memory. For example, patterns of neural activity in the hippocampus that occurred during the day will reoccur during sleep periods. By observing which neural patterns arise (and by correlating them to previous neural activity), one can actually guess what the rat is dreaming of.
  • The American psychiatrist Gregory Berns (of Emory University) is studying the brain circuits that are responsible for impulsive behavior such as playing the stock market, gambling, rooting for a soccer team. It turns out these are the same brain circuits that evolved to help us cope with survival issues (food, sex, danger). Those brain circuits are largely outside the sphere of influence of your "conscious" experience. We react by "instict" to those survival issues. Our brain seems to be built in such a way as to avoid "thinking" about issues that are a matter of life and death. As we acquire data from our surroundings, some of them are first processed by the and are "perceived" only after a response has already been programmed.
    The fact that trivial chores, such as investing in the stock market or rooting for a soccer team, also fall outside "conscious experience" lends credence to the theory that "most" of our cognitive life is unconscious. Several cognitive scientists believe that we "think" only after we have already acted, and our self-awareness is a mere illusion. I pretend that I have been writing these lines because I wanted to, but in reality I wrote them under some kind of unconscious impulse and only afterwards do I realize that I wrote them.
    It all goes back to the circuits in the brain that pilot our behavior in the face of rewards. The circuits that assess "rewards" are driven by a chemical called dopamine, and are therefore referred to as the "dopamine system".
    In 1997 Swiss neuroscientist Wolfram Schultz developed a theory of how the dopamine system affects learning through the concept of "reward".
    Dopamine neurons respond to rewards. A good reward increases the activity of dopamine neurons, a mediocre reward has no effect on them and a disappointment (the opposite of a reward) depresses their activity. Basically, the dopamine system is an alarm bell. If the dopamine system is stable, the brain does not have to look into what has happened: the world is under control. If the dopamine system is subject to a change, then the brain has to look into what happened and "learn" something new: the reward signals that the action was a useful one, the disappointment signals that the action was a bad one. Whenever the dopamine system gets excited or depressed, some kind of learning occurs in the brain.
    While depevoled for survival purposes, the same dopamine system is vulnerable to "rewarding" signals from, say, the stock market and gambling.
  • The American anthropologist Michael Alvard has advanced the theory that the social behavior of humans arose with the adoption of carnivorous habits. Hunting is a cooperative process that may have fostered the evolution of cognitive skills such as altruism and language, and even politics and economy. The transition from solitarty foraging to group hunting changed the environmenal pressure that early hominids were subject to. Alvard also points out that the distribution of meat had to be "fair" in order to motivate individuals to cooperate (each individual had to "gain" something proportional to his contribution to the hunt). In other words, hunters needed relatively complex behavior, compared with solitary foragers.
January 2002
  • While studying the brain of monkeys, Ryohei Hasegawa of Kyoto University and National Eye Institute has discovered that neurons reflect past and predicted performance much more than they reflect current performance. (See their paper)
    Basically, the brain does not store current activity, but immediately computes future behavior in the face of a similar situation plus a "summary" of past events. Neurons are basically machines to predict the future. (See the debate on this experiment).
  • Chris Goodnow of the John Curtin School (Canberra, Australia, (His home page) and his student Stephen Martin (His home page) are studying immunological memory, or how the immune system remembers. Since we have learned of so many analogies between the immune system and the brain, this research could lead to a better understanding of brain memory as well. There is a kind of cell that provides a sort of barrier to future infections. Martin is trying to understand this kind of cell. An abstract of their work).

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