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global_barge-in_strategy [2018/08/21 11:30] 127.0.0.1 external edit |
global_barge-in_strategy [2019/08/08 10:46] (current) lisa.illgen_concentrix.com |
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| ===Types of barge-in=== | ===Types of barge-in=== | ||
| - | Older systems did not have barge-in capability, and required specialized user interface design. Because all modern systems permit barge-in, we will not address those specialized design principles. For information about them, see Balentine, et al. (1997) and Balentine & Morgan (2001). | + | Older systems did not have barge-in capability, and required specialized user interface design. Because all modern systems permit barge-in, we will not address those specialized design principles. For information about them, see [[references#balentine1997|Balentine, et al.]] (1997) and [[references#balentine2001|Balentine & Morgan]] (2001). |
| There are two types of barge-in for VoiceXML-compliant recognizers: hotword and speech. | There are two types of barge-in for VoiceXML-compliant recognizers: hotword and speech. | ||
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| ===Lombard speech and the "stuttering effect"=== | ===Lombard speech and the "stuttering effect"=== | ||
| - | In noisy environments, the tendency of speakers to raise their voice or otherwise exaggerate speech is known as Lombard speech (Lombard, 1911). | + | In noisy environments, the tendency of speakers to raise their voice or otherwise exaggerate speech is known as Lombard speech ([[references#lombard|Lombard, 1911]]). |
| - | After a caller begins speaking to barge into system speech, if the system speech continues playing for more than 300-500 ms, this can trigger a "stuttering effect" (Balentine & Morgan, 2001). Callers think the system didn't hear them, so they stop saying what they were saying and start over, which often completely confuses the recognizer. This can lead to a series of usability issues as the caller and system get out of sync. Note that the time of 500 ms is consistent with the amount of time it takes to resolve initiative conflicts in human-human conversation (Schegloff, 2000; Yang & Heeman, 2010). | + | After a caller begins speaking to barge into system speech, if the system speech continues playing for more than 300-500 ms, this can trigger a "stuttering effect" ([[references#balentine2001|Balentine & Morgan, 2001]]). Callers think the system didn't hear them, so they stop saying what they were saying and start over, which often completely confuses the recognizer. This can lead to a series of usability issues as the caller and system get out of sync. Note that the time of 500 ms is consistent with the amount of time it takes to resolve initiative conflicts in human-human conversation ([[references#schegloff|Schegloff, 2000]]; [[references#yang|Yang & Heeman, 2010]]). |
| ===Barge-in recommendations=== | ===Barge-in recommendations=== | ||
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| System speech should stop within 500 ms of the time a user begins barging in. | System speech should stop within 500 ms of the time a user begins barging in. | ||
| - | Failure to quickly stop system speech when callers barge in can cause serious usability problems, such as the "stuttering effect" (Balentine & Morgan, 2001; Schegloff, 2000; Yang & Heeman, 2010). | + | Failure to quickly stop system speech when callers barge in can cause serious usability problems, such as the "stuttering effect" ([[references#balentine2001|Balentine & Morgan, 2001]]; [[references#schegloff|Schegloff, 2000]]; [[references#yang|Yang & Heeman, 2010]]). |
| Potential exceptions to this guideline include disabling barge-in to: | Potential exceptions to this guideline include disabling barge-in to: | ||
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| **//If using hotword barge-in, strive for very concise prompting and responding//**\\ | **//If using hotword barge-in, strive for very concise prompting and responding//**\\ | ||
| - | The key advantage of hotword barge-in is its resistance to accidental interruption. Its primary disadvantage is its tendency to trigger the stuttering effect. This tendency can be overcome if users are trained in how to use the system effectively. If the design is for untrained callers in conditions of high ambient noise, one way to minimize the need to barge in is to keep the prompting and messaging very concise so the system speech finishes before a caller would have time to barge in. After all, even when a system allows barge-in, many callers prefer not to do so (Suhm, 2008). Another strategy is to promote short caller responses (trying to keep them to no more than 2-3 syllables). The typical time required to produce a syllable of speech is about 200 ms (Crystal & House, 1990; Massaro, 1975), so responses that are 2-3 syllables in length are less likely to trigger the stuttering effect. Also, provide plenty of pauses to give callers opportunities to begin speaking without actively interrupting the system. | + | The key advantage of hotword barge-in is its resistance to accidental interruption. Its primary disadvantage is its tendency to trigger the stuttering effect. This tendency can be overcome if users are trained in how to use the system effectively. If the design is for untrained callers in conditions of high ambient noise, one way to minimize the need to barge in is to keep the prompting and messaging very concise so the system speech finishes before a caller would have time to barge in. After all, even when a system allows barge-in, many callers prefer not to do so ([[references#suhm2008|Suhm, 2008]]). Another strategy is to promote short caller responses (trying to keep them to no more than 2-3 syllables). The typical time required to produce a syllable of speech is about 200 ms ([[references#crystal|Crystal & House, 1990]]; [[references#massaro|Massaro, 1975]]), so responses that are 2-3 syllables in length are less likely to trigger the stuttering effect. Also, provide plenty of pauses to give callers opportunities to begin speaking without actively interrupting the system. |
| **//Use hotword barge-in for wait/continue situations//**\\ | **//Use hotword barge-in for wait/continue situations//**\\ | ||