We are all acquainted with OPTICAL ILLUSIONS, illusions caused by the brain’s visual and perception systems playing tricks on us and characterized by visually perceived images that differ from objective reality. Here are 2 well-known examples:
“My Wife and My Mother-in-law” published in 1915 by cartoonist W.E. Hill
(Do you see both an old and a young woman?)
This “widget” is an impossible object!! Can you see why?
These and other optical illusions work because of the structures and processes of our brains. Similarly, there are also “AUDIO ILLUSIONS” that work because of the brain’s auditory processing structures and processes. Here are 3 AUDIO ILLUSIONS. Because they are AUDIO ILLUSIONS, you have to be able to hear them to appreciate them! Also, for the 2nd AUDIO ILLUSION, the McGurk effect, you have to be able to SEE the screen as well as HEAR the audio.
AUDIO ILLUSION #1 – Additional Info Sure Helps!
In the following audio clip, Jayatri Das, Chief Bioscientist at Franklin Institute Science Museum demonstrates how our brain uses additional information to make sense out of an otherwise unintelligible sound sequence. (This will blow your mind!!) Click the image to hear.
AUDIO ILLUSION #2 McGurk Effect
This Audio Illusion is stunning! Your brain uses visual information to make sense of the audio information it is receiving! Even when you know what is going on, it doesn’t seem to change its effect!!! Click the image below to hear this AUDIO ILLUSION. (Remember, for this AUDIO ILLUSION to work, you have to be able to SEE this clip as well as HEAR it!)
AUDIO ILLUSION #3 Shepard Tone Effect
A SHEPARD TONE is named after Roger Shepard (born 1929). Technically, it is a sound created by a superposition of sine waves separated by octaves and where the bass tone either moves up or down. What you hear is an AUDIO ILLUSION of a tone that continually ascends or descends but that ultimately never seems to go higher or lower!!! Click on the image below to hear the SHEPARD TONE EFFECT in ascending form. (There is also a descending form.)
The SHEPARD TONE EFFECT is explained in the following video clip.