Curious, I ask, “How do you recognize a place?”
“That’s easy,” you say. “I just see familiar objects that are usually located at the same spatial coordinates they previously occupied. Seeing is the key for sighted people. But, honestly, I have great admiration for anyone whose sight is highly impaired and for the sightless. I can’t imagine dealing with the world as efficiently as they do. Where’s their reference? How do they determine coordinates in a place where there are either diminished or missing visual signals?”
“Good question,” I respond. Now imagine the problem bats have. They seem to navigate at high speed among objects without bumping into them. Birds crash into dining room windows, but not a single bat has hit the house. Maybe Dieter Vandereist of the University of Antwerp is onto something in his recent research.* He thinks that bats use ‘templates’ to orient themselves by recognizing the echo signatures of objects. That finding ties memory to navigation. But how do the bats perceive the objects they use for locating place? Dr. Goerlitz of the University of Bristol appears to have discovered a key component of echo location, the process of sonar that bats use to avoid bumping into things in the dark.** After trying to fool bats by sending out sound through a speaker to mimic echoes, Goerlitz and his colleagues realized that real objects have a signature sound aperture, sound reflection angles that ‘impinge on a bat’s ears.’ It isn’t just the size of an object and the strength of its echo that tell a bat that there’s an obstacle in its path; it’s the combination of sound reflection angles that bats use to identify and avoid an object. The bats did not avoid the virtual objects the speakers projected into their flight paths. They didn’t see the virtual objects as real objects.”
“Whoa!” you exclaim. “This is far too much bat science for me. What’s the use in these studies, anyway?”
“I guess curiosity is prime, but there is at least another reason to understand how bats recognize and maneuver to and through a place. Simon Whiteley of the University of Strathclyde says that if we can understand how bats accomplish traveling in the dark, we can apply the process to robots. Egyptian fruit bats send out double clicks that last only a quarter of a millisecond that return with less acoustic energy. Somehow the bats amplify the echoes. From an application to robot awareness of place to human awareness: Imagine a future technology that enables blind people to recognize place almost as easily as sighted people by ‘seeing’ as bats see, that is, by hearing their environment.”
“As you find your way home or to some other familiar place today, think about the clues you use to make the mental maps you have created to recognize and navigate. Enhancing your awareness of your clues won’t make you a neuroscientist, an acoustic engineer, or a biologist. It will, however, help to explain the way you connect with any place. And, since you are always ‘in a place,’ your awareness can teach you something about how (and why) you became familiar with wherever you are at the moment. Those who would connect to the present to ‘live in the present’ can find no better starting point than the place where the present occurs.”
*Dieter Vanderelst et al, Place recognition using batlike sonar, eLife (2016). DOI: 10.7554/eLife.14188; Read more at: http://phys.org/news/2016-08-echo-templates-aid-mental.html#jCp
** Holger R Goerlitz, Daria Genzel & Lutz Wiegrebe (2011): Bats‘ avoidance of real and virtual objects: implications for the sonar coding of object size. Behavioural Processes, online first. www.sciencedirect.com/science/article/pii/S0376635711002245 ; Read more at: http://phys.org/news/2011-11-path.html#jCp
*** Tuesday 11 May, in IOP Publishing's Bioinspiration & Biomimetics http://iopscience.iop.org/1748-3190/5/2/026001
“That’s easy,” you say. “I just see familiar objects that are usually located at the same spatial coordinates they previously occupied. Seeing is the key for sighted people. But, honestly, I have great admiration for anyone whose sight is highly impaired and for the sightless. I can’t imagine dealing with the world as efficiently as they do. Where’s their reference? How do they determine coordinates in a place where there are either diminished or missing visual signals?”
“Good question,” I respond. Now imagine the problem bats have. They seem to navigate at high speed among objects without bumping into them. Birds crash into dining room windows, but not a single bat has hit the house. Maybe Dieter Vandereist of the University of Antwerp is onto something in his recent research.* He thinks that bats use ‘templates’ to orient themselves by recognizing the echo signatures of objects. That finding ties memory to navigation. But how do the bats perceive the objects they use for locating place? Dr. Goerlitz of the University of Bristol appears to have discovered a key component of echo location, the process of sonar that bats use to avoid bumping into things in the dark.** After trying to fool bats by sending out sound through a speaker to mimic echoes, Goerlitz and his colleagues realized that real objects have a signature sound aperture, sound reflection angles that ‘impinge on a bat’s ears.’ It isn’t just the size of an object and the strength of its echo that tell a bat that there’s an obstacle in its path; it’s the combination of sound reflection angles that bats use to identify and avoid an object. The bats did not avoid the virtual objects the speakers projected into their flight paths. They didn’t see the virtual objects as real objects.”
“Whoa!” you exclaim. “This is far too much bat science for me. What’s the use in these studies, anyway?”
“I guess curiosity is prime, but there is at least another reason to understand how bats recognize and maneuver to and through a place. Simon Whiteley of the University of Strathclyde says that if we can understand how bats accomplish traveling in the dark, we can apply the process to robots. Egyptian fruit bats send out double clicks that last only a quarter of a millisecond that return with less acoustic energy. Somehow the bats amplify the echoes. From an application to robot awareness of place to human awareness: Imagine a future technology that enables blind people to recognize place almost as easily as sighted people by ‘seeing’ as bats see, that is, by hearing their environment.”
“As you find your way home or to some other familiar place today, think about the clues you use to make the mental maps you have created to recognize and navigate. Enhancing your awareness of your clues won’t make you a neuroscientist, an acoustic engineer, or a biologist. It will, however, help to explain the way you connect with any place. And, since you are always ‘in a place,’ your awareness can teach you something about how (and why) you became familiar with wherever you are at the moment. Those who would connect to the present to ‘live in the present’ can find no better starting point than the place where the present occurs.”
*Dieter Vanderelst et al, Place recognition using batlike sonar, eLife (2016). DOI: 10.7554/eLife.14188; Read more at: http://phys.org/news/2016-08-echo-templates-aid-mental.html#jCp
** Holger R Goerlitz, Daria Genzel & Lutz Wiegrebe (2011): Bats‘ avoidance of real and virtual objects: implications for the sonar coding of object size. Behavioural Processes, online first. www.sciencedirect.com/science/article/pii/S0376635711002245 ; Read more at: http://phys.org/news/2011-11-path.html#jCp
*** Tuesday 11 May, in IOP Publishing's Bioinspiration & Biomimetics http://iopscience.iop.org/1748-3190/5/2/026001
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