User:MikaylaS2000/sandbox

Humans are fairly susceptible to illusions, regardless of our innate ability to process complex stimuli. Confirmation bias is believed to be largely responsible for the inaccurate judgments that we make when evaluating information, given that humans typically interpret and recall information that appeals to their own biases. Amongst these misinterpretations, known as illusions, falls the category of auditory illusions. Auditory illusions are false perceptions of a real sound or outside stimulus. These false perceptions are the equivalent of an optical illusion: the listener hears either sounds which are not present in the stimulus, or sounds that should not be possible given the circumstance on how they were created. The brain uses multiple senses simultaneously to process information, however, spatial processing of stimuli is handled by the visual sense, whereas temporal processing of stimuli is handled by the auditory sense. The auditory and visual experiences differ in that auditory is non-spatial and is much less detailed than visual. 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. When someone is experiencing an auditory illusion, their brain is falsely interpreting its surroundings and distorting their perception of the world around them. While illusions may offer amusement, it is important to understand the important insights they bring to our understanding of how the brain processes both auditory and visual stimuli.

Sounds that are found in words are called embedded sounds, and these sounds are the cause of some auditory illusions. In order to prevent hearing echo created by perceiving multiple sounds coming from different spaces, our auditory system relates the sounds as being from one source. A person's perception of a word can be influenced by the way they see the speaker's mouth move, even if the sound they hear is unchanged. For example, if someone is looking at two people saying "far" and "bar", the word they will hear will be determined by who they look at. If these sounds are played in a loop, the listener will be able to hear different words inside the same sound. People with brain damage can be more susceptible to auditory illusions and they can become more common for that person.

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. Combination tones are illusions that are not physically present as sound waves, but rather, they are created by one's one neuromechanics. According to Purwins, auditory illusions have been used effectively by various composers such as Beethoven (Leonore Overture), Berg (Wozzeck), Krenek (Spiritus Intelligentiae, Sanctus), Ligeti (Études), Violin Concerto, Double Concerto, for flute, oboe and orchestra), Honegger (Pacific 231), and Stahnke (Partota 12).