A sound is heard as coming from a plausible visible source, such as a moving mouth, even when it comes from somewhere else.
Howard and Templeton named the effect in their 1966 survey of spatial orientation, after the stage ventriloquist whose voice seems to come from the dummy. In 2004 David Alais and David Burr showed that the pull is not fixed: when the visual cue was sharp, it captured the sound, but when it was blurred, the sound captured the sight.
In practice
- A cinema audience hears dialogue from an actor's mouth although the speakers are behind and beside the screen.
- A television viewer hears a laptop's voice coming from the face on its screen rather than from the speaker grille below it.
- Possible explanations
- The modern account is that the brain combines sight and sound in proportion to how precise each is about location. Vision usually locates things better, so it usually wins, but a degraded visual signal reverses the balance.
- In its favour
- It is one of the best-replicated findings in multisensory perception, and the Alais and Burr results fit a statistically optimal model of cue combination closely.
- Against it
- Researchers note that it depends on the sound and sight occurring close together in time and plausibly belonging together, so it is a weighting rather than a fixed dominance of vision, and older accounts that described it as vision simply overriding hearing are now considered too simple.
- Standing
- Makes cinema sound work. Compare the McGurk Effect and Synchresis.
- Further reading
- Wikipedia
- Subject
- Psychology & Behavior
- Essay
- A century and a half of measuring the mind