Delays of a quarter- or half-second have different effects on various
kinds of communications. However, we are concerned here only with what
they might do to telephone conversations. Time delay will affect
conversations in two ways. One of these—pure delay—depends on the nature
of speech and the way people use it to converse; the other—echo—has to
do with the nature of the world’s telephone systems.
The first effect can be illustrated by an example. Suppose that George
in Paris is talking to me in New York. He says, “Do you want to go?” and
I answer “Yes” immediately upon hearing the word “go.” But that word
didn’t arrive in New York until a quarter of a second after George said
it, and my reply was delayed another quarter-second, so George hears my
instantaneous reply a half-second late. Under some circumstances, he
might interpret this delay to mean that I was less than enthusiastic
about going. We don’t know exactly what response times people expect in
conversation, or how much variation in such intervals they can tolerate.
But it has been assumed that delays of a half-second or more would make
a noticeable and perhaps disturbing difference. A little later on, I
will describe an experiment dealing with this first effect. But first we
must briefly discuss the second effect of delay on telephone
conversation, to show why we decided to try to isolate the first effect
and study it separately.