Kathy Sierra has an interesting article about the impact of audio on people’s perception of video quality.
I don’t have a link handy, but there’s a study that showed that the quality of the audio causes people to change their evaluation of the quality of the visuals, but that it doesn’t work in reverse.
Creating Passionate Users: The effect of sound on users
Basically she is saying that on average people will rank the visual part of a video as higher quality if the sound is good and lower quality if the sound is bad. However, if you keep the sound quality constant and change the video quality it won’t impact their perception of the audio quality.
I tried looking for a copy of that research and I came across a study in the May 2004 issue of International Journal of Human-Computer Studies where they were studying the perception of quality of multimedia training. One of the interesting things that they found was that increased exposure to video will result in a lower perception of quality.
In another study published in Journal of Research in Music Education in the summer of 2004, researchers studied whether the attractiveness of the musician impacted their evaluation of their music. They had people rate the quality of performance from an audio recording, the attractiveness of the performer from videos when they weren’t performing, and the quality of the performance from a video. They found that people who watched the video were biased in favor of the more attractive female performers, but against the male performers who were considered more attractive.
All these performers were playing the piano, so I wonder if some of these results were from a stereotype that girls should play the piano and not boys. However the study found that overall the technical merits of each performance were more accurately ranked from the videos that from the audio alone. (Of course this might be because young performers tend to grimace when they make a mistake even if the listeners wouldn’t have noticed from the audio alone.)
In yet another study from the June 2002 issue of Cognitive Brain Research researchers discovered that they could create visual illusions through auditory stimulus. Basically they would flash a light once at someone and play different sounds in their ears. By changing the sound they could make the person percieve multiple flashes of light even though there was only one. They attributed this to “perceptual interactions”.
I wasn’t able to find the article she mentioned, but it is very true that the quality of audio has a lot to do with the perceived quality of a video. If anyone finds the original study that she is refering to I’d like to see it.