What is an illusion? According to one definition, an illusion is “a mismatch between the immediate visual impression and the actual properties of the object,” said Michael Bach, a vision scientist, and professor of neuron biophysics at the University of Freiburg Eye Hospital in Freiburg, Germany. Essentially, an illusion “tricks your eyes” so to speak. It makes you see something that is not exactly there, like a crooked line that is actually straight or a moving dot that is not moving at all. Or in this case, it may make the letter M look like the letter W.
What’s Happening in the Brain During an Optical Illusion?
One theory why illusions occur involves the “brain’s need to take shortcuts,” according to Susana Martinez-Conde, director of the laboratory of visual neuroscience at Barrow Neurological Institute in Phoenix, Ariz. That seems to be the case of this puzzle. Since the brain sees many Ws, it assumes that the entire page is full of them when this is not the case.
Another theory for illusions is that it occurs when the brain is trying to guess the future in the next tenth of a second. Therefore, you don’t see the actual image but what the brain expected it to be. “Illusions occur when the brain attempts to perceive the future, and those perceptions don’t match reality,” explained Mark Changizi, a neurobiologist and assistant professor of cognitive science at Rensselaer Polytechnic Institute in Troy, N.Y. 
While illusions are not completely understood, they could still be experienced. Try it for yourself with this visual puzzle.
How Many “M”s Could You See?
Your brain might be filling in all the spaces with Ws, blotting out the Ms. However, instead of trying to fight to concentrate, try relaxing your gaze. Your eyes should be able to pick out the shapes that are different from the others. It seems counter-intuitive to relax your eyes instead of actively searching for the Ms, but it’s actually very helpful. Scroll when you’ve counted as many Ms as you could for the correct answer.
Answer: There are 10 Ms in total. Here are their exact locations:
How many Ms did you find? Did relaxing your eyes work? If you like this puzzle, here are some more to test your thinking and observing skills:
- Can You Correctly Count The Number Of People In This Tricky Puzzle?Here’s A Puzzle That’s Baffling So Many Adults! Can You Guess The Right Answer?
- How Many Eggs Are Left? People Are Left Confused By This Tricky Puzzle About Eggs
- Majority Of Readers Struggle To Spot Mismatching Character In Picture Puzzles
- Find Out If Your Vision Is Sharp With This Puzzle: Can You See What Is In The Image?
- “Optical Illusions: When Your Brain Can’t Believe Your Eyes.” ABC News. Cari Nierenberg.