Decades of Discovery - 1940s
Experimental psychologist Alvin Liberman joins the Laboratories to assist in developing a “sound alphabet,” an auditory Braille, as it were, to represent the letters in a text for use in a reading machine for the blind. Cooper and Liberman find, however, that because the ear’s ability to resolve a rapid sequence of discrete sounds into its components is limited, no acoustic code they devise can convey text at more than one-tenth the typical rate of speech. Guiding research questions now become:
Why is speech so much more effective than other acoustic signals? How do we speak so fast? How does speech evade limits on the temporal resolving power of the ear? How is reading related to speech perception? And, more generally, is there some special, perhaps biologically ordained, relation between speech and the structure of language?
The conclusions of this and other research at the Laboratories appear in Blindness: Modern Approaches to the Unseen Environment, edited by co-investigator Paul Zahl. This influential book, published in 1950, identifies scientific and technical obstacles that must be overcome to develop practical devices to assist blind mobility and reading.