Intelligibility And The Brain Model - Polycom SoundStation VTX1000 Reference Manual

THE "BRAIN" MODEL OF INTELLIGIBILITY IN BUSINESS TELEPHONY
• The nature of discussions makes accuracy critical, so the many ways that
telephones distort speech and degrade accuracy carry a real cost to business.
• Users are often talking to people that they do not know and have never met
before. A phone call is the first impression for both parties in a high-value
relationship.
• Phone calls often occur between people who have different native languages or
dialects, so accented speech is added to the other burdens of telephony.
• Conferences occur among groups, which increases both the cost and the
potential value of the meeting due to the number of participants and the
difficulty of scheduling them. Yet, to accomodate such a group, the quality of
the sound must be degraded because some kind of speakerphone is required.
This can introduce room reverberation, fan noise, clipping and feedback,
interruptions, and multiple participants sitting near and far away.
• Having multiple talkers participating in a conference makes fast and accurate
identification of who is talking more important, but also more difficult.
• Meetings can be very long, yet require sustained attention. This puts an
increased strain on sound quality, because small differences in speakerphone
performance add up to big differences in fatigue and attention.

Intelligibility and the BRAIN Model

For all these reasons, intelligibility (how easily speech is understood) is especially critical
in business telephony. Yet perversely, the challenges to intelligibility are magnified in the
group settings that are so common in business. Let us look at the components of speech
intelligibility.
We hear and understand speech in three main stages, which are called here the physical,
cognitive, and analytical. In the physical stage, speech is carried from the talker's mouth
to the listener's ears, and the fidelity with which this is done is paramount. In the cognitive
stage, the listener resolves ambiguities in what she's heard by applying simple reasoning,
such as grammatical and accent rules, to the local context of the word. And finally, in the
analytical stage, those words that are not resolved through the first two stages are
subjected to more intense scrutiny, examining the troubling words in broader contexts to
see if their identities can be inferred.
These second two layers of comprehension are increasingly distracting. Additionally,
there are instances such as speech from foreign talkers, where the assumptions of these
contextual anallyses do not hold: a person who does not share the same native language
or dialect will likely use entirely different words or sounds than those that are expected.
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