The often quoted pioneering study by Reeves and Voelker of Stanford University (Effects of Audio-Video Asynchrony on Viewer’s Memory, Evaluation of Content and Detection Ability) concluded that when audio is early relative to video, the lip sync error is unconsciously disturbing to the viewer. The experience of this disturbance is then transferred to the primary content of the message being viewed – the consumer may view the person speaking as less believable, less interesting, less successful or less honest. In addition, negative evaluation due to the unconscious lip sync error will cause the program material to be remembered well – perhaps the worst commercial outcome of a persuasive message.

Therefore, if your message is informational (news programming, corporate and educational programming), entertainment (sports, talk shows, soap operas) or sales (commercials, infomercials), the negative effects of lip sync errors can cause the viewer to “tune out”. Whether this “tuning out” is literal (changing the channel) or figurative, the net result is the same – you are not reaching your audience.

The sharper images of high definition programming may aggravate lip sync error problems because viewers can see lips more clearly. Research is underway comparing the effects of audio to video synchronization problems in high definition and standard definition versions of the same program material. Initial results suggest that viewers are more sensitive to (and affected by) lip sync errors in the HD version. This means that the monitoring of lip sync errors will be even more important in HD.

The bottom line – lip sync errors must be measured at all stages of the production and distribution process to ensure maximum perceived value of the underlying message.