A Look at the Troxler Effect

You might already recognize the illusion that we are touching on today. Especially if you have been keeping up with MOI NYC blog for a while now. We included the Troxler effect in our April Fool’s post because we love how simple, yet effective it is. We have several pieces that demonstrate the Troxler effect in the galleries of the museum. So, we thought we would take some time to break down the fascinating science behind the illusion. 

So, keep reading to learn a little bit more about our favorite fading illusion. Once you do, you’ll be sure to want to schedule a visit to the museum to experience it in person!

What is the Troxler Effect?

The Troxler effect (also known as Troxler fading) was first discovered by Swiss physician and philosopher Ignaz Paul Vital Troxler. The effect was first recorded in 1804 when he observed that staring at a fixed point for an extended period of time would cause the peripheral areas of the image to fade away. You may have experienced this when you have become fixated on something or found yourself “zoning” out. However, the effect is best experienced in an image such as the one below.

Troxler's Fading Circle. A red dot inside of a blue circle, the optical illusion will cause the blue circle to fade away when you stare at the red dot.
The Troxler’s Fading Circle optical illusion. Stare at the red dot in the center. If you can’t see it, try enlarging or zooming in on the image.

Stare for an extended period of time at the red dot in the center of the circle. You will notice the blue circle starts to fade away. 

How does the Troxler Effect Work?

The Troxler Effect is another example of “filling in the gap.” We have referenced this phenomenon many times on our blog. When we say “filling in the gap,” we are describing the way that the human brain fills in the gaps in perception when there is a factor clearly missing. 

In the case of the Troxler effect, the brain is deeming the blue circle as “less important” than the red dot. Instead of working to show you the red dot and the blue circle at once, it’s filling in the blue portion with the background color. Thus, allowing you to focus solely on the red center. Our brains do this to allow for easier processing of things that seem more “important.” If we were constantly registering everything within our peripheral field of vision, it would be a lot harder to focus on anything. 

How the Effect Works in the Eye

Without getting too scientific (we’ll leave that to your ophthalmologist), we also want to talk about how the Troxler effect transmits the image to the brain through the eye. When you are fixing your gaze on an image, your eye is never completely still. Instead, it undergoes rapid movements called “saccades.” These saccades cause the image to be constantly refreshing so your brain gets an up-to-date view. As the image refreshes, the blue circle slowly fades away. 

The way that the Troxler effect works is a great example of why optical illusions are still important to this day. They help scientists, philosophers, and physicians understand brain/eye function and health. Believe it or not, brain/eye function is a field in which there is always more to learn. 

Experiencing the Troxler effect in person, alongside the rest of our illusions at the Museum of Illusions NYC is a great time for the whole family. You can learn about why and how illusions work the way they do while having fun. Science made fun. Is there anything better? Click here to book your visit to the Museum of Illusions NYC. We can’t wait to show you around!