Monday, 13 June 2011

In the dark

In 2009 (see Echoes of SF) I mentioned Daniel F Galouye's SF novel Dark Universe, in post-apocalypse survivors live in a cave system in total darkness, finding their way by echolocation using "clickstones".  At the time, I'd only just encountered the reality that human echolocators exist in the real world. At the time, a Times article - Blind taught to ‘see’ like a bat - mentioned that no scientific research had been done on the technique. However, Felix Grant just sent me the 2011 paper "Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Expert" 1, which reports functional brain scan results on blind users of the technique, showing that they actually use the primary visual cortex to process the sound data. As the work of Daniel Kish shows, the method is teachable, but it appears unclear if it's generally learnable or if you need a innate aptitude to excel at it.

Addendum: PLoSBLOGs has a very good overview of the subject: Getting around by sound: Human echolocation, by Greg Downey.

This brings me to an Exeter connection: James Holman FRS, aka "The Blind Traveller". An Exeter-born naval officer, he went blind at 25. Kicking against the restrictions of being pensioned-off to a ghastly ritual posting at Windsor Castle that involved twice-daily church attendance, he instead went to university, then on a Grand Tour of Europe, and then on extensive and intrepid world travels. He's the historical poster boy for human echolocation, and is said to have accomplished this using a tapped cane or ambient sounds such as the hoofbeats of horses.

I say "said to" because while his echolocation methods are mentioned in many modern books and articles, I can't find mention of them in any of Holman's travelogues, nor in other contemporary accounts of him; William Jerdan's 1866 Men I Have Known, for instance, just talks of his other senses being intensified in a general way, and Holman's own preface to his 1834 The narrative of a journey, undertaken in ... 1819, 1820 & 1821, through France, Italy, Savoy, Switzerland, parts of Germany bordering on the Rhine, Holland, and the Netherlands says

... it must, however, not be forgotten, that the loss of one sense, is uniformly compensated by superior powers of those that remain unimpaired, in consequence of their being more called into action; and it is well known, that the sense of touch, in particular, acquires so great a delicacy, as to afford degrees of information, which under ordinary states it is incapable of: besides this advantage, he acquired an undefinable power, almost resembling instinct, which he believes in a lively manner gives him ideas of whatever may be going forward externally.

But however he did it, the achievement is remarkable. His travel works are online at the Internet Archive.

Such extensive travel journals require notes, and a point of of interest is how Holman made them.  Mostly, as you'd expect, by dictation, but described in A Voyage round the World: Volume 1, pages 6-7, he also used a device he called the "Nocto via Polygraph", shown in the frontispiece of the fifth edition of The Narrative of a Journey (here). Invented and sold by Ralph Wedgwood of London, the device - variously called a Noctograph or Noctopolygraph ("nocto" for night, "poly" because it produced duplicates) comprised a rectangular frame crossed by parallel brass wires, that held two sheets of plain paper with carbon paper sandwiched between. The user wrote with a stylus, guided by the wires, the carbon creating the prints (one original, one reversed copy) on the plain paper. The top-of-range modes had stretchy spring grids so that you could write proper descenders on letters. There's an detailed account of the device , and its advantages and difficulties, on pages 117-118 of George Ticknor's 1864 Life of William Hickling Prescott.

Although Wedgwood's device was a well-known, and patented, one, the idea wasn't wildly original. The Catholic Encyclopedia's section Education of the Blind has a good historical overview of the many similar devices assisting the blind in writing:

... the tablets of Généresse (1807) and of Bruno, the typhlograph of Passard, Dr. Nord's skotograph, Dr. Woizechowsky's amaurograph, Count de Beaufort's stylograph, Wedgewood's noctograph, and the writing-frames of the Elliot brothers, of Thursfield, Dooley, and Levitte.
line-cell frames or tablets, the best known are those devised by the Rev. Joseph Engelmann of Linz (1825), James Gall of Edinburgh, Mercier-Capette, Hebold, Dr. Llorens of Barcelona, by C. E. Guldberg of Copenhagen (1858), Galimberti of Milan, Martuscelli of Naples, Moon of Brighton, England, Kemps of Grave, Holland, Ballu, Brother Isidore of Woluwe-Saint-Lambert, Belgium, and Mlle Mulot of Angers, France.

These gadgets weren't solely for blind users. One with a literary connection is the Nyctograph, a fairly low-tech version devised by Charles Lutwidge Dodgson (a.k.a. Lewis Carroll) for making notes in the night. This constrained the writing even more into a shorthand, each letter written in a square pigeonhole in a card grid.

Any one who has tried, as I have often done, the process of getting out of bed at 2 a.m. in a winter night, lighting a candle, and recording some happy thought which would probably be otherwise forgotten, will agree with me it entails much discomfort. All I have now to do, if I wake and think of something I wish to record, is to draw from under the pillow a small memorandum book containing my Nyctograph
- Lewis Carroll, letter to The Lady magazine, October 29, 1891

It's an odd thought that over a century later, I'm still using a very similar setup; the Graffiti input system on my Palm M100 organiser, which uses a cut-down shorthand alphabet written with a stylus in a square area, doesn't seem conceptually far different.

- Ray

1. Thaler L, Arnott SR, Goodale MA (2011) Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts. PLoS ONE 6(5): e20162. doi:10.1371/journal.pone.0020162.

No comments:

Post a Comment