The Blind Swordsman, the hero of an old Japanese film series (1962-1989), whose sword could ‘listen to the wind’ was pure fantasy—but now we know that it was entirely possible—he could be using echolocation! If bats can catch tiny insects in the dark, blind, by using echolocation (Bio-sonar), even distinguishing between kinds of insects, then humans, being fellow mammals, can also develop that capacity. In fact, we probably all use some echolocation in our daily activities without being aware of it. Yes, we, batmen all!
In a 1941 experiment at Cornell University in New York, Dallenback and colleagues demonstrated that sighted subjects could detect a large board as they approached it while blind-folded. At that time, this had been ascribed to ‘facial vision’ (a sort of skin sense) in psychology; but the Dallenbach experiments proved otherwise. They established that hearing alone was necessary for the detection of the boards by conducting experiments eliminating each sense perception separately.
When we walk into an empty classroom, without any furniture, we can tell it’s empty by the echoes in the sound of our footsteps; or even one with or without students in it. But we ignore that aural information because we can see very well the situation, which is not the case with a blind person. The blind, not having input to the visual brain from the eyes, can develop echolocation to a high degree, being able to hike, even mountain bike, and otherwise get around quite normally. For example they could tell a telephone pole from a tree or find a ball in a park by clicking their tongue and hearing the echoes coming back from the objects, with varied degrees of delay. See video.
Now here’s the strange thing: in a blind person who is practiced in echolocation, it has been found that it was his visual brain that was ‘seeing’ the objects and their location, motion, weight and texture. His auditory brain was no more active than during normal hearing—same as a sighted subject who was blind-folded and who did not echolocate. The visual brain becomes even more active in someone with more experience in echolocation than one who’s new to it—but shows no activity in someone who does not echolocate (Goodale et al, 2011). The authors suggest that a blind person whose visual brain is no longer useful can use it to process information from another sense, like hearing or touch. The part of the visual brain (V1) in this case is the area normally responsible for judging space and orientation information from the eyes.
In the Dolphin Research Center in the Florida Keys, trainers have demonstrated that a dolphin can imitate a trainer spinning in the water or performing other movements next to it, even after it was blind-folded. When unable to see, the dolphin switched to echolocation, probably automatically. Imitation, of course, is an important human attribute by which we learn, starting as babies. Babies largely use their eyes to observe and imitate actions. But can humans use echolocation to imitate others as well?
William Forsythe’s (American, b. 1949 New York) dance company (formerly Ballett Frankfurt), since the 1980s, has been known for its radical new approach to dance, pushing the limits of ballet’s traditions. But, as Forsythe explains to Sarah Crompton in the Telegraph in 2012, “it is about the process of people imitating one another, of replication. That is what one does. One starts by standing behind someone else and imitating what they do”. This is the starting point of his Artifact (1984), a dance he choreographed with over 30 dancers who then proceed to dance in an apparently rather chaotic and un-uniform fashion. It is as if they start from the beginning, like all babies and animals, then move on to allow individual freedom of expression, going beyond copying into creation. Creation is what we believe only humans are capable of, an act that is more than looking for food. Forsythe was also thinking of a time past when ballet was more “improvisatory”, and visceral.
Dana Caspersen, Forsythe’s wife and fellow dancer, explains thus:
“….Bill’s dancing is extremely complex and organic, and the key to understanding how to do his choreography lies in figuring out which points on his body are initiating movement and which are responding to the initiation… This inner response, which we call residual movement, is refraction like light bouncing between surfaces. In order for it to be effective, it cannot be decorative, applied after the fact, but must be the result of skeletal-muscular coordination reacting to the original movement impulse.”
“We use Bill’s movement in its original form as phrase, and then it was transformed and splintered…In this case, the movement that occurred naturally from Thomas and me dancing together, using Bill’s movement, shaped the physical nature of the piece … This kind of material collision is also used in The Loss of Small Detail (1991). Loss was the first piece in which Bill started working on the idea of “disfocus”, of moving away from strong, outwardly directed visual focus and heading towards a “trance” state…”
It is in this “trance” state, then, when the highly trained and disciplined body is able to express all its unconsciously-retained prior learning, abstracting it into geometric motions and to thoughts like ‘Cartesian duality’ of body and mind (or the blurring of it).* Forsythe dances are frequently geometric in form, often performed amongst or with four-legged rectangular tables (See link).
See also in this video how a dancer delineates with his hands, elbows or feet sheer straight lines or rhomboid shapes (around 1:01) that look eerily similar to the rhomboid muscle in our upper back which is involved in his raising his elbow in this position.
In Forsythe’s 2011 Sider, dancers carry around rectangles of corrugated cardboards, dancing with them and with each other, in no discernible pattern, merely responding to each other while wearing earphones that feed them various texts and commands. With such competition for the dancers’ (and the audiences’) attention, no wonder everyone should be reduced to that “trance” state of “disfocus”, of pure bodily sensations, allowing access, perhaps, to the ancient and unconscious parts of our body-brain. Now I wonder, if some echolocation is at work here, with hearing privileged over seeing, helped by those boards? And that those dancers are temporarily using part of their visual brain via their hearing? Here’s Forsythe again, who wants to bring learning back to its beginning, via direct transmission, not through words or theories:
“The rhythmical inflections of Elizabethan theater [think Shakespeare], like those of classical dance, have been sustained by a tradition of transmission from performer to performer for over 400 years. In »Sider«, these intricate patterns of speech are communicated to the performers via the soundtrack of a filmed version of a late 16th century tragedy. The adherence of the performers’ actions to this vocal score instigates disquieting configurations of incongruous musicality that underscore the drama’s themes of analogy and obscuration.”
Blind tennis. It was invented by a blind man in Japan in the 1980s. As it is now played, tennis balls are equipped with noise-making devices; and it is probably all aural with no echolocation involved. However, it is possible that players can be equipped with a higher frequency sound-emitting device—SSD (Sensory Substitution Device) – or even a variable one like the bats have (tongue-clicks being too slow)—the brain could then be trained to discern the echoes to better pinpoint the ball as it approaches. Such a device is now available but of course human trial is a complicated process. From what we know now about our brain’s adaptive nature, and its vast size compared to that of a tiny bat, there is no reason why it should not work.
* Dancers and actors often use ‘muscle memory’ to describe the quick, direct, and instinctual improvisations on stage.
NEWS & UPDATES
Insectivorous bats form mobile sensory networks to optimize prey localization: The case of the common noctule bat https://www.pnas.org/doi/full/10.1073/pnas.2203663119
5/31/2015 As we can squint our eyes to better zoom in for finer details in our visual field, so can the bats with their bio-sonar echolocation to zero in on smaller objects. They do so (for mouth-emitting bats), by changing their mouth gape to narrow or widen the beam. See report in the Proceedings of the National Academy of Sciences. The knowledge could potentially help us refine our sonar-based SSD (Sensory Substitution Device) for blind people.
5/27/2014 Yale University teaches dance students physics as way to study choreography. See report in physics magazine Symmetry.
5/8/2014 William Forsythe coming to sunny Los Angeles after 30 years in cold Northern Europe!!