Forrester Research of Cambridge, Mass., said sales of "emotion detection" technology to corporate call centers has reached $400 million annually.
Forrester said sales are still growing for the systems and a related technology known as "speech analytics," The Washington Post reported Wednesday.
The technologies, which were originally developed for eavesdropping, have been employed by customer service agents to get a better idea of customers' moods.
Donna Fluss, principal with DMG Consulting LLC in West Orange, N.J., said emotion detection, which tracks volume and pitch, grew out of voice verification technology.
Fluss said both emotion detection and speech analytics use recorded and transcribed conversations to sort them by searchable words and phrases.
Health insurer Wisconsin Physicians Service, for example, uses the technology to scan automated phone calls for "Medicare" and "confused" to find calls from seniors with Medicare questions.
Roger Woolley, vice president of marketing for speech analytic software seller eTalk, of Irving, Texas, said subtler systems are used to identify when an angry customer is preparing to cancel services.
Copyright 2006 by United Press International
Explore further: How artificial intelligence will transform how we gesture