The importance of attention, localization, and source separation to speech cognition and recall
David Griesinger · The Journal of the Acoustical Society of America · 2014
Acoustic standards for speech are based on word recognition. But for successful communication sound must be detected, separated from noise and other streams, phones, syllables, and words must be recognized and parsed into sentences, meaning must be found by relating the sentences to previous knowledge, and finally information must be stored in long term memory. All of these tasks require time and working memory. Acoustical conditions that increases the difficulty of any part of the task reduce recall. But attention is possibly the most important factor in successful communication. There is compelling anecdotal evidence that sound profoundly and involuntarily influences attention. Humans detect in fractions of a second whether a sound source is close, independent of its loudness and frequency content. When sound is perceived as close it demands a degree of attention that distant sound does not. The mechanism of detection relies on the phase relationships between harmonics of complex tones in the vocal formant range, properties of sound that also ease word recognition and source separation. We will present the physics of this process and the acoustic properties that enable it. Our goal is to increase attention and recall in venues of all types.