The Oxford Dictionary defines a sense as “a faculty by which the body perceives an external stimulus.” Most people can name five – sight, smell, hearing, taste, and touch – but some scientists reckon we could have as many as 33, including equilibrioception (the sense of balance) and nociception (the sense to feel pain). In the not-too-distant future, humankind may be able to add even more to the list thanks to rapid advances in technology.
However, if you think you can trust your senses, you are sadly mistaken. Here are eight illusions that prove exactly that.
An optical trick known as “White’s Illusion” was developed by an Australian psychologist called Dr Michael White after he spotted an unusual design by an 11th-grade student in a book on optical art. The illusion involves just three shades: black, white, and gray. Yet, most people see four. This is because of the way the gray is embedded into the black and white stripes, which makes it look as though there are in fact two shades of gray.
It’s not known what causes this phenomenon, but several researchers have put it down to a concept called the belongingness theory. Essentially, our perception of the gray blocks is shaped by the color of the lines surrounding it, so when it is embedded in black lines, it appears darker and when it is surrounded by white lines, it looks lighter. The exact same thing happens when color is added to the mix.
We also see something similar with Edward H. Adelson's checker shadow illusion.
Believe it or not, tile A is the same color as tile B. Yet, our brain "adjusts" the color to compensate for the perceived shadow.
Still don't believe us?