Auditory Illusions: How Our Brains Can Be Fooled
Humans are fairly susceptible to illusions, despite an innate ability to process complex stimuli. Amongst these misinterpretations, known as illusions, falls the category of auditory illusions. There are a multitude of examples out in the world of auditory illusions. But that does not prevent people from being fooled by auditory illusions.
Example of Shepard Tone, an auditory illusion.
Causes of Auditory Illusions
Many auditory illusions, particularly of music and of speech, result from hearing sound patterns that are highly probable, even though they are heard incorrectly. This is due to the influence of our knowledge and experience of many sounds we have heard. Spatial information is processed with greater detail and accuracy in vision than in hearing. In order to prevent hearing echo created by perceiving multiple sounds coming from different spaces, the human auditory system relates the sounds as being from one source.
Embedded Sounds
Sounds that are found in words are called embedded sounds, and these sounds are the cause of some auditory illusions.
Confirmation Bias
Confirmation bias is believed to be largely responsible for the inaccurate judgments that people make when evaluating information, given that humans typically interpret and recall information that appeals to their own biases.
Spatial Components of Music
Composers have long been using the spatial components of music to alter the overall sound experienced by the listener. One of the more common methods of sound synthesis is the use of combination tones.
The McGurk effect demonstrates how visual information can influence what we hear.
Auditory System and Sound Perception
Auditory illusions highlight areas where the human ear and brain, as organic survival tools, differentiate from perfect audio receptors; this shows that it is possible for a human being to hear something that is not there and be able to react to the sound they supposedly heard.
Examples of Auditory Illusions
Here are some examples of auditory illusions:
- McGurk Effect: A perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception. The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to the perception of a third sound.
- Shepard Tone: A sound consisting of a superposition of sine waves separated by octaves. When played with the highest and lowest frequencies fading in and out, it creates the illusion of a tone that continually ascends or descends in pitch, yet never seems to get any higher or lower.
The table below summarizes the key factors contributing to auditory illusions discussed in this article:
| Factor | Description | Example |
|---|---|---|
| Embedded Sounds | Sounds within words that can trick our perception. | Hearing a different word than what is actually spoken. |
| Confirmation Bias | Our tendency to interpret information in a way that confirms our existing beliefs. | Misinterpreting lyrics in a song to fit a preconceived notion. |
| Spatial Audio Manipulation | Using spatial components in music to alter the perceived sound. | Creating a sense of movement or distance through sound. |
| Visual Influence | Visual cues affecting auditory perception. | McGurk Effect |