Are There 11 or 17 Colors in This Picture? Science Explains Confusing Optical Illusion

Social media had gone back to the time when counting colors was a thing. A strange optical illusion was posted earlier this month on Twitter about the different shades of purple that divides the internet as to the real count of shades it has.

People on the internet are debating how many different shades of purple there are in the image, with some saying they only see 11 colors while others even went on to see 17 colors.

This viral photo was posted by Twitter user @0UTR0EG0 on February 4, saying: "How many colors do you see???? I see 3."

The different colors seen in the image are due to Mach Bands Illusion, named after an Austrian physicist, wherein two colors join and a person may see different shades even if it does not exist. Other theories also include the lighting and even the person's sex.

Mach Bands Illusion Explains Why We See Different Shades of Colors

Mach Bands Illusion is named after Austrian physicist Ernst Mach, the same scientist who studied gas dynamics and lent his name to the ratio of an object's speed to the speed of sound. But this time, his interest had more to do with sight.

During the 1860s, he worked as a mathematics professor at the University of Graz when he developed an interest in optics and acoustics.

According to ScienceAlert, Mach was fascinated by an illusion similar to the image shared by @0UTR0EG0 on Twitter. He thought how similar colors of slightly contrasting shades become so easily distinguishable when they touch but difficult to distinguish when separated.

He believed that something is going on inside the eyeball, more specifically within the photosensitive tissue that makes up the retina, the science news website reported. These bands of shaded stripes are now known as the Mach Bands in honor of him.

In this day and age, researchers tested Mach's theory using better technology. They confirmed that Mach's claims on the mechanics behind the retinal behavior called lateral inhibition are accurate.

Evolution has taught humans to distinguish patterns more easily among similar shades. The brain tells the other cells next to the light-sensitive cell to shush whenever the latter sends a signal, making little difference between groups of cells that are all shushing each other.

Meanwhile, when a quieter group of cells sits next to the louder cells, the inhibitory influence over cells right on the boundary effectively enhances the difference between the shades of colors.

The Number of Shades We See May Depend on One's Sex

Dr. Michael J. Proulx, a neuroscientist and an expert in perception and cognition at the University of Bath, told MailOnline that the number of shades people see might even depend on one's sex.

He pointed out that even though humans see more or less see the same range of the electromagnetic spectrum, there are still some differences. For instance, humans are usually trichromatic, wherein three cone cells combine to see colors.

But some are color blind who only have two types of cone cells that reduce their ability to see color. This dichromacy case is more common in males than in females.

Moreover, tetrachromacy also refers to more than three cone cells in the eyes that make people see more colors than other people. This condition is most common in females.

Besides, other people also have different optics that screen the incoming light and have different cone cells. These differences could explain why some see more or fewer colors than others.

Check out more news and information on Optical Illusions and Perceptions in Science Times.