“I have an audio stigmatism whereby I hear things wrong – I have audio illusions.”Tom Waits

Most people are familiar with optical illusions. But ears can be tricked just as easily.

Auditory illusions are false perceptions of a real sound or outside stimulus. These false perceptions are the counterpart of an optical illusion: the listener hears either sound which is not present or sounds that should not be possible given the circumstance of how they were created. There are different audio illusions.

McGurk effect

McGurk effect is a perceptual phenomenon including an interaction between hearing and vision in speech perception. The illusion happens when one sound’s auditory element is paired with another sound’s visual element, directing the perception of a third sound.

The visual information is coming from seeing a person speak changes how they hear the sound. If a person has poor quality auditory information but good quality visual information, they may be more likely to experience the McGurk effect.

Different individuals are affected differently by the McGurk effect based on many factors, including brain damage and other disorders.

The Shepard Illusion:

Auditory illusions are embedded within the music that we love. Take the famous Shepard Tone, for example. Named after the California-based neuroscientist Roger Shepard, the tone is a complex mixture of “sine waves.” These waves are continuously raised in pitch, only to be dropped down an octave, such as a waterwheel mechanism.

Ventriloquism Illusion

Ventriloquism, perceiving sound coming from an object that is, in fact, silent, is one example. A definitive example of this illusion is a performer on a stage with a puppet next to them. The performer talks while moving their lips very carefully and making visible movements with the puppet’s mouth. Therefore, the inanimate puppet seems to be the one making the jokes.

Our assumptions and prior knowledge can affect our overall impression of something that occurs in our present reality.

Author: Azadeh Mozhdehfarahbakhsh

Image: Photo by Ernest Bachrach/NBC Hollywood/Wikimedia Commons