 Dolphin: Echolocation Game |  During this echolocation |  Human echolocation |  or Syndicate games. |
 Bat echolocation |  water with echolocation; |  Game Info : |  How Do Whales Use Echolocation |
 Echo Location Slugging.jpg |  uses Echolocation the same |  Spore (PC Games) |  same kind of acoustic fat |
 ECHOLOCATION Spinner dolphins |  Superpower: Super Echolocation |  Bats use echolocation to fly |  to he's echo location. |
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Juan Antonio Martínez detectando una columna por ecolocación
La emisión de determinados chasquidos de lengua ayuda a identificar los objetos de alrededor sin necesidad de verlos, algo especialmente útil para las personas ciegas.
“Los humanos podemos rivalizar con los murciélagos en la capacidad de ecolocación o biosónar bajo ciertas circunstancias”, señala Juan Antonio Martínez, autor principal del estudio e investigador de la Escuela Politécnica Superior de la UAH. El equipo que dirige el científico ha iniciado una serie de estudios pioneros en el mundo para poder usar la capacidad infrautilizada de ecolocación que tiene el ser humano.
En el primer trabajo, publicado en la revista Acta Acustica united with Acustica, el equipo analiza las propiedades físicas de varios sonidos y propone el más efectivo para su uso en la ecolocación. “El sonido casi ideal es el ‘clic palatal’, un chasquido que se origina poniendo la punta de la lengua en el velo del paladar, justo detrás de los dientes, y realizando un movimiento rápido hacia atrás, aunque es frecuente hacerlo erróneamente hacia abajo”, explica Martínez.
El investigador comenta que los clic palatales “tienen una forma muy similar a los sonidos que emiten los delfines -cambiando la escala-, aunque estos animales tienen órganos adaptados y pueden hacer 200 clic por segundo y nosotros sólo 3 ó 4”. Con la ecolocación, “que es tridimensional y permite atravesar materiales que son opacos a la radiación visible”, se puede medir la distancia de un objeto por el tiempo que transcurre entre la emisión de una onda acústica y la recepción del eco o la onda reflejada en ese objeto.
Para aprender a emitir, recibir e interpretar los sonidos los científicos están desarrollando un método con una serie de protocolos. El primer paso es que el individuo sepa ejecutar e identificar sus propios sonidos (son diferentes para cada persona), y después saber utilizarlos para distinguir los objetos según sus propiedades geométricas, “como lo hace el sónar de los barcos”.
Hasta ahora algunas personas invidentes habían aprendido la ecolocación de forma autodidacta, “por ensayo y error”. Los casos más conocidos son los estadounidenses Daniel Kish, el único ciego que ha conseguido el certificado de guía de otra persona invidente, y Ben Underwood, considerado como el mejor “ecolocador” del mundo hasta su fallecimiento a comienzos de 2009.
Pero para desarrollar esta capacidad no se requieren condiciones físicas especiales. “Con dos horas al día durante un par de semanas se puede distinguir si tienes un objeto delante, y en otras dos semanas, diferenciar los árboles de una acera”, revela a SINC Martínez.
El científico recomienda probar con el típico sonido “ch” que se emite cuando se quiere hacer callar a la gente. El movimiento por delante de la boca de un bolígrafo, por ejemplo, enseguida se nota. Es un fenómeno parecido al que ocurre cuando se viaja en un coche con las ventanillas bajadas y se “escuchan” los huecos cercanos a la orilla de la carretera.
El siguiente nivel de aprendizaje sería dominar los “clic palatales”. Para comprobar que los ecos de los chasquidos de lengua se interpretan correctamente los investigadores trabajan con la ayuda de un puntero láser, que señala la parte del objeto a donde se dirige el sonido.
Martínez ha adelantado a SINC que ya están trabajando para que una persona sorda y ciega pueda utilizar en el futuro este método, porque los ecos se perciben no sólo a través del oído, sino también mediante vibraciones que llegan a la lengua y a los huesos. “Para este tipo de personas en particular, y para cualquiera en general, sería una nueva forma de percibir el mundo”.
Otra de las líneas de investigación del equipo se centra en establecer los límites biológicos de la capacidad de ecolocación en humanos, “y los primeros resultados indican que la resolución en detalle podría rivalizar incluso con la propia vista”. De hecho los investigadores comenzaron distinguiendo que tenían a una persona delante, pero ahora ya pueden detectar algunos órganos internos, como los huesos, e incluso “ciertos objetos del interior de un bolso”.
Los científicos reconocen que están empezando en este campo, pero las posibilidades que se abren con el desarrollo de la ecolocación humana son enormes. Esta técnica será muy práctica no sólo para personas invidentes, sino también para profesionales como los bomberos (podrían localizar los huecos de las salidas entre el humo) y los equipos de rescate, o simplemente para una persona perdida entre la niebla.
La mejor comprensión de los mecanismos mentales de la ecolocación también podría contribuir a diseñar nuevas tecnologías de imagen médica o escáneres que aprovechen la gran capacidad de penetración de los clics. Martínez destaca que estos sonidos “son tan penetrantes que incluso en ambientes tan ruidosos como el metro se pueden sentir las discontinuidades que se producen en el andén o en los túneles”.
Juan Antonio Martínez Rojas, Jesús Alpuente Hermosilla, Pablo Luis López Espí y Rocío Sánchez Montero. “Physical Analysis of Several Organic Signals for Human Echolocation: Oral Vacuum Pulses”. Acta Acustica united with Acustica 95 (2): 325-330, 2009.
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La ecolocación o biosónar es la capacidad de ciertos animales para explorar su entorno a través del análisis de la información sonora contenida en los ecos de sonidos que ellos mismos producen. Los casos más paradigmáticos de ecolocación son los delfines, la mayoría de ballenas y los murciélagos, aunque otro pequeño número de animales comparten esta habilidad, como los géneros de aves Aerodramus, Hydrochous, Schoutedenapus y Collocalia, así como los guácharos de la especie Steatornis caripensis, las musarañas de los géneros Sorex y Blarina y la familia de los Tenrecidae en Madagascar.
Se ha comprobado que el cerebro de los murciélagos y los delfines posee una zona especializada para la ecolocación, pero en el caso de la especie humana se desconoce si existe una región parecida o alguna otra asume esta función mediante el aprendizaje. La monitorización de la actividad cerebral por tomografía de emisión de positrones (PET), mientras una persona está usando está capacidad, podría ayudar a resolver el misterio.
Fuente: FECYT – Fundación Española para la Ciencia Y Tecnología y UAH
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A team of researchers from the University of Alcalá de Henares (UAH) has shown scientifically that human beings can develop echolocation, the system of acoustic signals used by dolphins and bats to explore their surroundings. Producing certain kinds of tongue clicks helps people to identify objects around them without needing to see them, something which would be especially useful for the blind.
"In certain circumstances, we humans could rival bats in our echolocation or biosonar capacity", Juan Antonio Martínez, lead author of the study and a researcher at the Superior Polytechnic School of the UAH, tells SINC. The team led by this scientist has started a series of tests, the first of their kind in the world, to make use of human beings' under-exploited echolocation skills.
In the first study, published in the journal Acta Acustica united with Acustica, the team analyses the physical properties of various sounds, and proposes the most effective of these for use in echolocation. "The almost ideal sound is the 'palate click, a click made by placing the tip of the tongue on the palate, just behind the teeth, and moving it quickly backwards, although it is often done downwards, which is wrong", Martínez explains.
The researcher says that palate clicks "are very similar to the sounds made by dolphins, although on a different scale, as these animals have specially-adapted organs and can produce 200 clicks per second, while we can only produce three or four". By using echolocation, "which is three-dimensional, and makes it possible to 'see' through materials that are opaque to visible radiation" it is possible to measure the distance of an object based on the time that elapses between the emission of a sound wave and an echo being received of this wave as it is reflected from the object.
In order to learn how to emit, receive and interpret sounds, the scientists are developing a method that uses a series of protocols. This first step is for the individual to know how to make and identify his or her own sounds (they are different for each person), and later to know how to use them to distinguish between objects according to their geometrical properties "as is done by ships' sonar".
Some blind people had previously taught themselves how to use echolocation "by trial and error". The best-known cases of these are the Americans Daniel Kish, the only blind person to have been awarded a certificate to act as a guide for other blind people, and Ben Underwood, who was considered to be the world's best "echolocator" until he died at the start of 2009.
However, no special physical skills are required in order to develop this skill. "Two hours per day for a couple of weeks are enough to distinguish whether you have an object in front of you, and within another two weeks you can tell the difference between trees and a pavement", Martínez tells SINC.
The scientist recommends trying with the typical "sh" sound used to make someone be quiet. Moving a pen in front of the mouth can be noticed straightaway. This is a similar phenomenon to that when travelling in a car with the windows down, which makes it possible to "hear" gaps in the verge of the road.
The next level is to learn how to master the "palate clicks". To make sure echoes from the tongue clicks are properly interpreted, the researchers are working with a laser pointer, which shows the part of an object at which the sound should be aimed.
A new way of seeing the world
Martínez has told SINC that his team is now working to help deaf and blind people to use this method in the future, because echoes are not only perceived by their ear, but also through vibrations in the tongue and bones. "For these kinds of people in particular, and for all of us in general, this would be a new way of perceiving the world".
Another of the team's research areas involves establishing the biological limits of human echolocation ability, "and the first results indicate that detailed resolution using this method could even rival that of sight itself". In fact, the researchers started out by being able to tell if there was someone standing in front of them, but now can detect certain internal structures, such as bones, and even "certain objects inside a bag".
The scientists recognise that they are still at the very early stages, but the possibilities that would be opened up with the development of echolocation in humans are enormous. This technique will be very practical not only for the blind, but also for professionals such as firemen (enabling them to find exit points through smoke), and rescue teams, or simply people lost in fog.
A better understanding of the mental mechanisms used in echolocation could also help to design new medical imaging technologies or scanners, which make use of the great penetration capacity of clicks. Martínez stresses that these sounds "are so penetrating that, even in environments as noisy as the metro, one can sense discontinuities in the platform or tunnels".
References:
Juan Antonio Martínez Rojas, Jesús Alpuente Hermosilla, Pablo Luis López Espí y Rocío Sánchez Montero. "Physical Analysis of Several Organic Signals for Human Echolocation: Oral Vacuum Pulses". Acta Acustica united with Acustica 95 (2): 325-330, 2009.
Abstract:
Active human echolocation can be an extremely useful aid for blind people. Active echolocation can be trained with both artificial and organic signals. Organic signals offer some advantages over artificial ones. Very detailed studies of organic signals in animals have been done. However, in the case of humans, the scientific literature is very scarce and not systematic. This is the first paper of a series on the properties of several suitable sounds for human echolocation. In this work, we offer a detailed analysis of these sounds, comparing their merits from a physical point of view. The results of this study have important applications to design systematic and optimized training protocols for accurate echolocation awareness.
One of the greatest thinkers in physics says the human brain—and the universe itself—must function according to some theory we haven't yet discovered.
From the September 2009 issue; published online October 6, 2009
Roger Penrose could easily be excused for having a big ego. A theorist whose name will be forever linked with such giants as Hawking and Einstein, Penrose has made fundamental contributions to physics, mathematics, and geometry. He reinterpreted general relativity to prove that black holes can form from dying stars. He invented twistor theory—a novel way to look at the structure of space-time—and so led us to a deeper understanding of the nature of gravity. He discovered a remarkable family of geometric forms that came to be known as Penrose tiles. He even moonlighted as a brain researcher, coming up with a provocative theory that consciousness arises from quantum-mechanical processes. And he wrote a series of incredibly readable, best-selling science books to boot.
And yet the 78-year-old Penrose—now an emeritus professor at the Mathematical Institute, University of Oxford—seems to live the humble life of a researcher just getting started in his career. His small office is cramped with the belongings of the six other professors with whom he shares it, and at the end of the day you might find him rushing off to pick up his 9-year-old son from school. With the curiosity of a man still trying to make a name for himself, he cranks away on fundamental, wide-ranging questions: How did the universe begin? Are there higher dimensions of space and time? Does the current front-running theory in theoretical physics, string theory, actually make sense?
Because he has lived a lifetime of complicated calculations, though, Penrose has quite a bit more perspective than the average starting scientist. To get to the bottom of it all, he insists, physicists must force themselves to grapple with the greatest riddle of them all: the relationship between the rules that govern fundamental particles and the rules that govern the big things—like us—that those particles make up. In his powwow with DISCOVER contributing editor Susan Kruglinksi, Penrose did not flinch from questioning the central tenets of modern physics, including string theory and quantum mechanics. Physicists will never come to grips with the grand theories of the universe, Penrose holds, until they see past the blinding distractions of today’s half-baked theories to the deepest layer of the reality in which we live.
You come from a colorful family of overachievers, don’t you?
My older brother is a distinguished theoretical physicist, a fellow of the Royal Society. My younger brother ended up the British chess champion 10 times, a record. My father came from a Quaker family. His father was a professional artist who did portraits—very traditional, a lot of religious subjects. The family was very strict. I don’t think we were even allowed to read novels, certainly not on Sundays. My father was one of four brothers, all of whom were very good artists. One of them became well known in the art world, Sir Roland. He was cofounder of the Institute of Contemporary Arts in London. My father himself was a human geneticist who was recognized for demonstrating that older mothers tend to get more Down syndrome children, but he had lots of scientific interests.
How did your father influence your thinking?
The important thing about my father was that there wasn’t any boundary between his work and what he did for fun. That rubbed off on me. He would make puzzles and toys for his children and grandchildren. He used to have a little shed out back where he cut things from wood with his little pedal saw. I remember he once made a slide rule with about 12 different slides, with various characters that we could combine in complicated ways. Later in his life he spent a lot of time making wooden models that reproduced themselves—what people now refer to as artificial life. These were simple devices that, when linked together, would cause other bits to link together in the same way. He sat in his woodshed and cut these things out of wood in great, huge numbers.
So I assume your father helped spark your discovery of Penrose tiles, repeating shapes that fit together to form a solid surface with pentagonal symmetry.
It was silly in a way. I remember asking him—I was around 9 years old—about whether you could fit regular hexagons together and make it round like a sphere. And he said, “No, no, you can’t do that, but you can do it with pentagons,” which was a surprise to me. He showed me how to make polyhedra, and so I got started on that.
Are Penrose tiles useful or just beautiful?
My interest in the tiles has to do with the idea of a universe controlled by very simple forces, even though we see complications all over the place. The tilings follow conventional rules to make complicated patterns. It was an attempt to see how the complicated could be satisfied by very simple rules that reflect what we see in the world.
The artist M. C. Escher was influenced by your geometric inventions. What was the story there?
In my second year as a graduate student at Cambridge, I attended the International Congress of Mathematicians in Amsterdam. I remember seeing one of the lecturers there I knew quite well, and he had this catalog. On the front of it was the Escher picture Day and Night, the one with birds going in opposite directions. The scenery is nighttime on one side and daytime on the other. I remember being intrigued by this, and I asked him where he got it. He said, “Oh, well, there’s an exhibition you might be interested in of some artist called Escher.” So I went and was very taken by these very weird and wonderful things that I’d never seen anything like. I decided to try and draw some impossible scenes myself and came up with this thing that’s referred to as a tri-bar. It’s a triangle that looks like a three-dimensional object, but actually it’s impossible for it to be three-dimensional. I showed it to my father and he worked out some impossible buildings and things. Then we published an article in the British Journal of Psychology on this stuff and acknowledged Escher.
Escher saw the article and was inspired by it?
He used two things from the article. One was the tri-bar, used in his lithograph called Waterfall. Another was the impossible staircase, which my father had worked on and designed. Escher used it in Ascending and Descending, with monks going round and round the stairs. I met Escher once, and I gave him some tiles that will make a repeating pattern, but not until you’ve got 12 of them fitted together. He did this, and then he wrote to me and asked me how it was done—what was it based on? So I showed him a kind of bird shape that did this, and he incorporated it into what I believe is the last picture he ever produced, called Ghosts.
Is it true that you were bad at math as a kid?
I was unbelievably slow. I lived in Canada for a while, for about six years, during the war. When I was 8, sitting in class, we had to do this mental arithmetic very fast, or what seemed to me very fast. I always got lost. And the teacher, who didn’t like me very much, moved me down a class. There was one rather insightful teacher who decided, after I’d done so badly on these tests, that he would have timeless tests. You could just take as long as you’d like. We all had the same test. I was allowed to take the entire next period to continue, which was a play period. Everyone was always out and enjoying themselves, and I was struggling away to do these tests. And even then sometimes it would stretch into the period beyond that. So I was at least twice as slow as anybody else. Eventually I would do very well. You see, if I could do it that way, I would get very high marks.
You have called the real-world implications of quantum physics nonsensical. What is your objection?
Quantum mechanics is an incredible theory that explains all sorts of things that couldn’t be explained before, starting with the stability of atoms. But when you accept the weirdness of quantum mechanics [in the macro world], you have to give up the idea of space-time as we know it from Einstein. The greatest weirdness here is that it doesn’t make sense. If you follow the rules, you come up with something that just isn’t right.
In quantum mechanics an object can exist in many states at once, which sounds crazy. The quantum description of the world seems completely contrary to the world as we experience it.
It doesn’t make any sense, and there is a simple reason. You see, the mathematics of quantum mechanics has two parts to it. One is the evolution of a quantum system, which is described extremely precisely and accurately by the Schrödinger equation. That equation tells you this: If you know what the state of the system is now, you can calculate what it will be doing 10 minutes from now. However, there is the second part of quantum mechanics—the thing that happens when you want to make a measurement. Instead of getting a single answer, you use the equation to work out the probabilities of certain outcomes. The results don’t say, “This is what the world is doing.” Instead, they just describe the probability of its doing any one thing. The equation should describe the world in a completely deterministic way, but it doesn’t.
Erwin Schrödinger, who created that equation, was considered a genius. Surely he appreciated that conflict.
Schrödinger was as aware of this as anybody. He talks about his hypothetical cat and says, more or less, “Okay, if you believe what my equation says, you must believe that this cat is dead and alive at the same time.” He says, “That’s obviously nonsense, because it’s not like that. Therefore, my equation can’t be right for a cat. So there must be some other factor involved.”
When you accept the weirdness of quantum mechanics, you have to give up the idea of space-time as we know it from Einstein. You come up with something that just isn’t right.
So Schrödinger himself never believed that the cat analogy reflected the nature of reality?
Oh yes, I think he was pointing this out. I mean, look at three of the biggest figures in quantum mechanics, Schrödinger, Einstein, and Paul Dirac. They were all quantum skeptics in a sense. Dirac is the one whom people find most surprising, because he set up the whole foundation, the general framework of quantum mechanics. People think of him as this hard-liner, but he was very cautious in what he said. When he was asked, “What’s the answer to the measurement problem?” his response was, “Quantum mechanics is a provisional theory. Why should I look for an answer in quantum mechanics?” He didn’t believe that it was true. But he didn’t say this out loud much.
Yet the analogy of Schrödinger’s cat is always presented as a strange reality that we have to accept. Doesn’t the concept drive many of today’s ideas about theoretical physics?
That’s right. People don’t want to change the Schrödinger equation, leading them to what’s called the “many worlds” interpretation of quantum mechanics.
That interpretation says that all probabilities are playing out somewhere in parallel universes?
It says OK, the cat is somehow alive and dead at the same time. To look at that cat, you must become a superposition [two states existing at the same time] of you seeing the live cat and you seeing the dead cat. Of course, we don’t seem to experience that, so the physicists have to say, well, somehow your consciousness takes one route or the other route without your knowing it. You’re led to a completely crazy point of view. You’re led into this “many worlds” stuff, which has no relationship to what we actually perceive.
The idea of parallel universes—many worlds—is a very human-centered idea, as if everything has to be understood from the perspective of what we can detect with our five senses.
The trouble is, what can you do with it? Nothing. You want a physical theory that describes the world that we see around us. That’s what physics has always been: Explain what the world that we see does, and why or how it does it. Many worlds quantum mechanics doesn’t do that. Either you accept it and try to make sense of it, which is what a lot of people do, or, like me, you say no—that’s beyond the limits of what quantum mechanics can tell us. Which is, surprisingly, a very uncommon position to take. My own view is that quantum mechanics is not exactly right, and I think there’s a lot of evidence for that. It’s just not direct experimental evidence within the scope of current experiments.
In general, the ideas in theoretical physics seem increasingly fantastical. Take string theory. All that talk about 11 dimensions or our universe’s existing on a giant membrane seems surreal.
You’re absolutely right. And in a certain sense, I blame quantum mechanics, because people say, “Well, quantum mechanics is so nonintuitive; if you believe that, you can believe anything that’s nonintuitive.” But, you see, quantum mechanics has a lot of experimental support, so you’ve got to go along with a lot of it. Whereas string theory has no experimental support.
I understand you are setting out this critique of quantum mechanics in your new book.
The book is called Fashion, Faith and Fantasy in the New Physics of the Universe. Each of those words stands for a major theoretical physics idea. The fashion is string theory; the fantasy has to do with various cosmological schemes, mainly inflationary cosmology [which suggests that the universe inflated exponentially within a small fraction of a second after the Big Bang]. Big fish, those things are. It’s almost sacrilegious to attack them. And the other one, even more sacrilegious, is quantum mechanics at all levels—so that’s the faith. People somehow got the view that you really can’t question it.
A few years ago you suggested that gravity is what separates the classical world from the quantum one. Are there enough people out there putting quantum mechanics to this kind of test?
No, although it’s sort of encouraging that there are people working on it at all. It used to be thought of as a sort of crackpot, fringe activity that people could do when they were old and retired. Well, I am old and retired! But it’s not regarded as a central, as a mainstream activity, which is a shame.
After Newton, and again after Einstein, the way people thought about the world shifted. When the puzzle of quantum mechanics is solved, will there be another revolution in thinking?
It’s hard to make predictions. Ernest Rutherford said his model of the atom [which led to nuclear physics and the atomic bomb] would never be of any use. But yes, I would be pretty sure that it will have a huge influence. There are things like how quantum mechanics could be used in biology. It will eventually make a huge difference, probably in all sorts of unimaginable ways.
In your book The Emperor’s New Mind, you posited that consciousness emerges from quantum physical actions within the cells of the brain. Two decades later, do you stand by that?
In my view the conscious brain does not act according to classical physics. It doesn’t even act according to conventional quantum mechanics. It acts according to a theory we don’t yet have. This is being a bit big-headed, but I think it’s a little bit like William Harvey’s discovery of the circulation of blood. He worked out that it had to circulate, but the veins and arteries just peter out, so how could the blood get through from one to the other? And he said, “Well, it must be tiny little tubes there, and we can’t see them, but they must be there.” Nobody believed it for some time. So I’m still hoping to find something like that—some structure that preserves coherence, because I believe it ought to be there.
When physicists finally understand the core of quantum physics, what do you think the theory will look like
I think it will be beautiful.
