Now that the 2020 bin-fire is in our rearview mirror, social media is back in the serious discussions that really matter. Like how many colors the thing has. one more time.
Earlier this month, a classic optical illusion was posted on Twitter with the question “How many colors do you see?” Poster saw three.
How many colors do you see ???? I see 3 pic.twitter.com/IgEHtyzebZ
– Jade (slow ♡) (@ 0UTR0EG0) February 4, 2021
Others answered with numbers as Up to 17. Tens of thousands of comments followed in a heated debate over what the “real” number should be.
Here at ScienceAlert we don’t have a strong opinion about how many bands featured in the image (it’s 11, right?). But we can help provide insight into what is likely to happen.
While it is difficult to say for sure, this phenomenon in the work is likely due to the influence of its first description by an Austrian physicist about a century and a half ago. Act seriouslyThe same world that I lent Unit name Comparing the speed of an object to the speed of sound.
Only in this case was Mach less interested in speed, and more in sight. While working as professor of mathematics and physics at the University of Graz in the 1860s, he developed a deep interest in optics and acoustics.
In 1865 he became interested in an illusion similar to the one we all marvel at now – similar colors of slightly contrasting shades that are easily distinguishable to the touch, but difficult to distinguish when separated.
Mach’s understanding was that something strange was happening inside the eyeball, specifically within the light-sensitive tissue that makes up the retina. Later, these shaded lines will be known as the Mach Bands in his honor.
Remarkably, his speculation was very strong. Since then, research using better technology than Mach had hoped to find has confirmed that the mechanisms behind this strange trick of the eye are reticulate behavior called Lateral inhibition.
This is 101: Your retina is a bit like a movie screen, in that it picks up light projected through the pupil. This screen is covered with receptors, some of which will react more powerfully under a brighter light and send a barrage of signals to the brain.
If we imagine two cells sending very similar signals to the brain, we might simply assume that they are of the same shadow. Our brain loves shortcuts, and in a crowded world it doesn’t have time to split hair.
But nature has developed a clever trick to help our brains more easily distinguish patterns between similar shades. When an individual light-sensitive cell sends a signal, it tells its immediate neighbors to be quiet.
This competition doesn’t make much of a difference between groups of cells that all scream and hit as loud as each other.
But when a quieter group of cells sits, interacting with the darker shade, next to the loud cells, this dampening effect on the cells at the boundary forces them to respond in a unique way, effectively enhancing the difference between the shades.
The diagram above may help to understand what is happening. The brighter light causes the receptors to stimulate their corresponding neurons more intensely. At the same time, each light-sensitive cell moisturizes the nerves of its neighbors.
The result is nerves at the boundaries between the different shades that send out signals that reinforce the difference, providing a clear borderline signal for your mind to pick up.
This ability plays a role in a variety of optical illusions, including a “sparkling web” of points that you cannot fully focus on.
While lateral doubling explains why our eyes are able to distinguish similar shades better when they’re side by side, it doesn’t quite explain why some of us I can not Tell the difference between colors of barely varying brightness, as in this illusion.
The inhibitory effects in our cells might be something that we all experience to a different extent, but it is also unlikely that it is the only factor that tells our brains how to interpret an image. Many of them will be unique to our eyes, our brains, computer screens, and the environments around us.
Ambient light sources will vary, differences in screen and screen brightness, and even the exact cellular makeup of the retina. Our minds will also add a level of correction in their unique way based on their expertise and hard wires.
Given the many variables, it is to be expected that not all of us will agree on exactly where the shade of pink stops and the next start.
This is all fun and games on Twitter, but understanding more about how our retina enhances the differences in shades it falls on can help us find ways. Improve our vision.
Now, bear in mind that we are not claiming to be experts in optics here at ScienceAlert. These are all speculations from one scientific writer who has a deep love for the psychology of delusions.
But we know that other than questions about the number of colors (or, more accurately, the hues, Tints and shadesIn the rectangle, there is some great biology that can tell us a lot about what we have in common.