The electric landscape

In his remarkable TED Talk "Can We Create New Senses for Humans?," neuroscientist David Eagleman describes the concept of the umwelt -- the part of the available stimulus space sampled by a particular animal's senses.  A simple example is the thin slice of the electromagnetic spectrum our eyes are sensitive to -- the familiar ROYGBIV of the rainbow.  There's plenty of electromagnetic radiation outside of that slice; gamma rays, x-rays, ultraviolet light, infrared light, microwaves, and radio waves are all ordinary photons, just like visible light is.  It's just that our eyes aren't sensitive to those frequencies, so they're outside of our umwelt.

The umwelt also has to do with the relative weighting of senses; how big a part of our sensory world a particular experience constitutes.  Most humans have a sense of smell, but my dogs live in a far richer olfactory world than I do.  But even how those inputs are utilized -- i.e., what kind of information they provide for making sense of the world -- can vary greatly.  Bats and dolphins use hearing in much the same way as we use our eyes, creating "sonic landscapes" of the objects around them.  What's kind of amazing, though -- and one of the main points of Eagleman's talk -- is that humans can train their brains to use other "peripherals" (as he calls them) to learn about the world, such as blind people who have learned to navigate the space around them by making clicking noises and listening for echoes from nearby obstacles.

It's always been fascinating to me to consider how the world would look to a night-flying echolocating bat.  Do they "see" their world through their ears and auditory cortex?

The topic of how other animals perceive their worlds -- and how different it could be from what we experience -- comes up because of a paper this week in the journal Nature about how elephantnose fish (Gnathonemus petersii), which live in murky streams in west and central Africa where eyesight doesn't serve much purpose, develop their visual picture of the world (including locating prey) using electric fields.  And not only do they gain information by creating and sensing electrical signals, they enhance those pictures using the signals created by nearby members of their species, making them one of the only known animals that relies on collective signal production and sensing.

Gnathonemus petersii [Image is in the Public Domain]

"Think of these external signals as electric images of the objects that nearby electric fish automatically produce and beam to nearby fish at the speed of light," said Federico Pedraja of Columbia University, who headed the study. "Our work suggests that three fish in a group would each receive three different "electrical views" of the same scene at virtually the same time."

The elephantnose fish's capacity for working in groups is a little like humans out on a search at night with flashlights.  One person with one flashlight would have a small illuminated field of view, but if there were twenty people it would go much faster, not only because of greater manpower, but because each person wouldn't be restricted to what is revealed by only their own flashlight beam.  Just as with twenty different flashlights in the night rather than a single one, in the case of elephantnose fish, the electrical fields produced by their neighbors clarify the picture they all receive.

"In engineering it is common that groups of emitters and receivers work together to improve sensing, for example in sonar and radar," said Nathaniel Sawtell, who co-authored the study.  "We showed that something similar may be happening in groups of fish that sense their environment using electrical pulses.  These fish seem to 'see' much better in small groups...  [They] have some of the biggest brain-to-body mass ratios of any animal on the planet.  Perhaps these enormous brains are needed for rapid and highly sophisticated social sensing and collective behavior."

To return to my original point -- how would the world look to an elephantnose fish?  Surely nothing like what we see.  Some sort of topography of electrical field strength, perhaps, creating an image of the obstacles they have to maneuver around, the prey they seek, and the predators they need to avoid.  But really, there's no way to know.  We're all trapped within our own umwelt.  I can't even imagine what the world is like for my dogs, who are a great deal more similar to me than these fish are.

To perceive the world like another living being does, you'd not only have to come equipped with their sensory systems, but put the information together using their brains.  We can only speculate, with all the inevitable biases that come from being locked in our own ways of knowing.  But this study did at least give us a hint of how different the world could appear -- if we were odd little fish living in muddy African rivers.

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Expanding the umwelt

The concept of the umwelt is a little mind-boggling.

It's defined as "the world as perceived by a particular organism."  In superficial terms we know that a dog must perceive life differently than we do.  For example, we know their senses of smell are a lot more keen than ours are, but the magnitude is staggering.  They have about fifty times the number of olfactory receptors than we do (three hundred million as compared to six million), so their world must be as vivid a tapestry of smells as ours is a tapestry of sights and sounds.

While it might be possible to imagine what it's like to have an enhanced sense, what about having a sense we lack entirely?  A number of animals, including sharks, platypuses, and knifefish, have an ability to sense electric fields, so the voltage change in the water around them registers as a sensory input, just as light or sound or taste does for us.  They use this sense to locate prey, because the neuromuscular systems of the animals they're hunting create a weak electrical discharge, which all of these animals can "see."

In the amazing 2015 TED Talk "Can We Create New Senses for Humans?",  neuroscientist David Eagleman explores what it would be like to expand our umwelt.  He has designed a vest, to be worn against the skin, that has a series of motors that create tiny vibrations.  The vest's input can be whatever you want; in one demonstration, sounds picked up by a microphone are the input used to create a pattern of vibrations on the chest and back.  With only a couple of days of training, a profoundly deaf individual was able to translate the patterns into a perception of the sounds, and correctly identify spoken words.

His brain had basically taken a different peripheral input device and plugged it into the auditory cortex!

Experiments with other "peripherals" have included using a pattern of weak electrical tingles transmitted onto the tongue via a horseshoe-shaped flat piece of metal to allow blind people to navigate around objects while walking, and even get good enough with it that they can throw an object into a basket.  One of Eagleman's experiments with the vest trained people using an input from an unidentified source -- all they did was press one of a pair of buttons and found out if their choice was right:

A subject is feeling a real-time streaming feed from the Net of data for five seconds.  Then, two buttons appear, and he has to make a choice.  He doesn't know what's going on.  He makes a choice, and he gets feedback after one second.  Now, here's the thing: the subject has no idea what all the patterns mean, but we're seeing if he gets better at figuring out which button to press.  He doesn't know that what we're feeding is real-time data from the stock market, and he's making buy and sell decisions.  And the feedback is telling him whether he did the right thing or not.  And what we're seeing is, can we expand the human umwelt so that he comes to have, after several weeks, a direct perceptual experience of the economic movements of the planet.

The wildest thing is that the peripheral you add doesn't have to be input; it can be output.  Two different papers, both in the journal Science, have shown that you can add an output device, and like with the inputs -- all it takes is a little training.

In the first, "A Brain-Computer Interface that Evokes Tactile Sensations Improves Robotic Arm Control," test subjects have a computer interface device implanted into their brain, which then translates thoughts into movements of a robotic arm, analogous to what an intact neuromuscular system is doing to our actual arms.  This has been doable for a while, but the advance in this study is that the robotic arm has sensors that provide feedback, again just like our own systems do when working properly.  Think about picking up a coffee cup; you adjust the pressure and position of your grip because you're constantly getting feedback, like the temperature of the cup, the weight and balance, whether your fingers are hanging on well or slipping, and so forth.

Here, the feedback provided by the sensors on the robotic arm cut in half the time taken for doing an action without mishap!  The brain once again picked up very quickly how to use the additional information to make the output go more smoothly.

In the second, people were trained with a "third thumb" -- an artificial extra digit strapped to the hand on the pinky-finger side.  It's controlled by pressure sensors under the toes, so you're using your feet to move something attached to your hand while simultaneously using your brain to control your other hand movements, which seems impossibly complicated.  But within a day, test subjects could perform tasks like building a tower from wooden blocks using the augmented hand... even when distracted or blindfolded!

Study author Paulina Kieliba, of University College - London's Institute of Cognitive Neuroscience, said, "Body augmentation could one day be valuable to society in numerous ways, such as enabling a surgeon to get by without an assistant, or a factory worker to work more efficiently.  This line of work could revolutionize the concept of prosthetics, and it could help someone who permanently or temporarily can only use one hand, to do everything with that hand.  But to get there, we need to continue researching the complicated, interdisciplinary questions of how these devices interact with our brains."

Co-author Tamar Makin summed it up: "Evolution hasn’t prepared us to use an extra body part, and we have found that to extend our abilities in new and unexpected ways, the brain adapts the representation of the biological body."

I think what amazes me most about all this is the flexibility of the brain.  The fact that it can adjust to such radical changes in inputs and outputs is phenomenal.  Me, I'm waiting for something like Tony Stark's suit in Iron Man.  That'd not only allow me to fight crime, but it'd make yard chores a hell of a lot easier.

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Too many people think of chemistry as being arcane and difficult formulas and laws and symbols, and lose sight of the amazing reality it describes.  My younger son, who is the master glassblower for the chemistry department at the University of Houston, was telling me about what he's learned about the chemistry of glass -- why it it's transparent, why different formulations have different properties, what causes glass to have the colors it does, or no color at all -- and I was astonished at not only the complexity, but how incredibly cool it is.

The world is filled with such coolness, and it's kind of sad how little we usually notice it.  Colors and shapes and patterns abound, and while some of them are still mysterious, there are others that can be explained in terms of the behavior of the constituent atoms and molecules.  This is the topic of the phenomenal new book The Beauty of Chemistry: Art, Wonder, and Science by Philip Ball and photographers Wenting Zhu and Yan Liang, which looks at the chemistry of the familiar, and illustrates the science with photographs of astonishing beauty.

Whether you're an aficionado of science or simply someone who is curious about the world around you, The Beauty of Chemistry is a book you will find fascinating.  You'll learn a bit about the chemistry of everything from snowflakes to champagne -- and be entranced by the sheer beauty of the ordinary.

[Note: if you purchase this book from the image/link below, part of the proceeds goes to support Skeptophilia!]