The Cat Telephone

Abstract

In lieu of an abstract, here is a brief excerpt of the content:

In 1929 two Princeton researchers, Ernest Glen Wever and Charles
W. Bray, wired a live cat into a telephone system and replayed the
telephone's primal scene. Following a procedure developed by
physiologists, Wever and Bray removed part of the cat's skull and
most of its brain in order to attach one electrode to the animal's
right auditory nerve and a second electrode to another area on the
cat's body. Those electrodes were then hooked up to a vacuum tube
amplifier by sixty feet of shielded cable located in a soundproof
room (separate from the lab that held the cat). After
amplification, the signals were sent to a telephone receiver. One
researcher made sounds into the cat's ear, while the other listened
at the receiver in the soundproof room (Wever and Bray 344).
The signals picked up off the auditory nerve came through the
telephone receiver as sound. "Speech was transmitted with great
fidelity. Simple commands, counting and the like were easily
received. Indeed, under good condition the system was employed as a
means of communication between operating and sound-proof rooms"
(Wever and Bray 345). After their initial success, Wever and
Bray checked for all other possible explanations for the
transmission of sound down the wire. They even killed the cat to
make sure there was no mechanical transmission of the sounds apart
from the cat's nerve: "[A]fter the death of the animal the response
first diminished in intensity, and then ceased" (Wever and Bray
346). As the sound faded from their cat microphone, it
demonstrated in the animal's death that life itself could power a
phone or any other electro-acoustic system-perhaps that life itself
already did power the telephone.
To put a Zen tone to it, the telephone existed both inside and
outside Wever and Bray's cat and, by extension, people. They
believed that they had proven the so-called telephone theory of
hearing, which had fallen out of favor by the late 1920s. Here it
is worth understanding both their error and their subsequent
contribution to hearing research. While Wever and Bray thought they
were measuring one set of signals coming off the auditory nerve,
they were actually conflating two sets of signals. The auditory
nerve itself either fires or does not fire and therefore doesn't
have a directly mimetic relationship to sound outside of it-there
is no continuous variation in frequency or intensity, as you would
have with sound in air. A series of experiments in 1932 revealed
that the mimetic signals they found were coming from the cochlea
itself. Called "cochlear microphonics," these signals were
responsible for the sounds coming out of Wever and Bray's speaker
in the soundproof room. Hallowell Davis wrote in a 1934 paper on
the subject:

The wave form of the cochlear response differs from that of the
nerve. From the latter we recover a series of sharp transients
having the wave form and the polarity characteristics of nerve
impulses [which fire three to four thousand times a second in the
auditory nerve but only about a thousand times a second in the
midbrain], while the cochlear response reproduces with considerable
fidelity the wave form of the stimulating sound waves. Even the
complex waves of the human voice are reproduced by it with the
accuracy of a microphone, while from most nervous structures there
is so much distortion and suppression of high frequencies that
speech may be quite incomprehensible.
(Davis 206)

Davis thus suggested that nerves are bad circuits for
reproducing sounds, but the cochlea is an excellent circuit for
reproducing sound-much like a microphone.
Davis and his collaborators' work on cochlear transmissions
paved the way for a wide range of subsequent research, and cochlear
microphonics are still important today. While they did challenge
Wever and Bray's conclusions about the telephone theory of hearing,
Davis and his collaborators continued down the same epistemological
path where ears and media were interchangeable; in fact, one was
best explained in terms of the other. One of the most widely
acknowledged and controversial achievements of this work has been
the development of cochlear implants. Previous treatments for
hardness of hearing...