Self-Motivation
David Goggins
Former Navy Seal
Career Development
Bryan Cranston
Actor
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Management
Chris Hadfield
Retired Canadian Astronaut & Author
Learn
from the world's big
thinkers
Start Learning

This optical illusion plays tricks on your brain

Check out these mysterious optical illusions that affect our visual perception.

If you look at the cross in the middle for at least 10 seconds, colorful spots on the sides will begin to fade away, courtesy of the Troxler effect.

  • Troxler's effect or "fading" causes images to disappear from your field of vision.
  • Scientists don't have a full understanding yet of how this works.
  • The effect is linked to the way neurons are adapted by the visual system.


Why do we some times see things that aren't there? Delighted by stories of vengeful ghosts and spirits, we largely assume there's a world outside of our regular field of vision. Whether it's inhabited is certainly debatable but the curious psychological condition called Troxler's Fading or Troxler's Effect may explain one optical illusion.

This effect is named after a Swiss physician and philosopher Ignaz Paul Vital Troxler (1780-1866), who discovered it in 1804. It is essentially a trick of perception that describes what happens if you fix your gaze upon a single point in the visual field. It doesn't even have to be for a long time – 10 seconds would do. That can make images and colors disappear from your peripheral vision.

THE LILAC CHASER

"Lilac chaser".

Look at the black cross at the center of the image and the spots in this "lilac chaser" illusion will fade away in a few seconds. A grey background and the cross will remain unless you are among those who will also see a moving blue-green spot. You might even notie a bunch of green spots when you move your eyes away after a while.

HOW DOES IT WORK?

Research indicates the effect is related to how neurons important for perceiving stimuli are adapted by the visual system. Unchanging stimuli will eventually disappear from our awareness while our mind will fill the areas where they used to be with the background information (or color). A "sensory fading" or "filling-in" is linked to saccades – involuntary eye movements that happen even when the gaze appears settled. If we fixate on a point, an unmoving image or scene would fade from view in a few seconds thanks to the "local neural adaptation of the rods, cones and ganglion cells in the retina," explains the Illusions Index.

The effect is made stronger if the stimulus image is low contrast or blurred.

While studies showed the effect doesn't only occur in the eyes but partially in the brain, there's not yet a definitive explanation for everything involved in this unusual visual phenomenon.

Another example image of the Troxler effect. Look at the center of the image for about 10 seconds.

And another fun example:

LIVE EVENT | Radical innovation: Unlocking the future of human invention

Innovation in manufacturing has crawled since the 1950s. That's about to speed up.

Big Think LIVE

Add event to calendar

AppleGoogleOffice 365OutlookOutlook.comYahoo


Keep reading Show less

Bubonic plague case reported in China

Health officials in China reported that a man was infected with bubonic plague, the infectious disease that caused the Black Death.

Vials Of Bacteria That May Cause Plague Missing From TX University

(Photo by Centers for Disease Control and Prevention/Getty Images)
Coronavirus
  • The case was reported in the city of Bayannur, which has issued a level-three plague prevention warning.
  • Modern antibiotics can effectively treat bubonic plague, which spreads mainly by fleas.
  • Chinese health officials are also monitoring a newly discovered type of swine flu that has the potential to develop into a pandemic virus.
Keep reading Show less

Self-driving cars to race for $1.5 million at Indianapolis Motor Speedway ​

So far, 30 student teams have entered the Indy Autonomous Challenge, scheduled for October 2021.

Illustration of cockpit of a self-driving car

Indy Autonomous Challenge
Technology & Innovation
  • The Indy Autonomous Challenge will task student teams with developing self-driving software for race cars.
  • The competition requires cars to complete 20 laps within 25 minutes, meaning cars would need to average about 110 mph.
  • The organizers say they hope to advance the field of driverless cars and "inspire the next generation of STEM talent."
Keep reading Show less

The dangers of the chemical imbalance theory of depression

A new Harvard study finds that the language you use affects patient outcome.

Image: solarseven / Shutterstock
Mind & Brain
  • A study at Harvard's McLean Hospital claims that using the language of chemical imbalances worsens patient outcomes.
  • Though psychiatry has largely abandoned DSM categories, professor Joseph E Davis writes that the field continues to strive for a "brain-based diagnostic system."
  • Chemical explanations of mental health appear to benefit pharmaceutical companies far more than patients.
Keep reading Show less
Videos

Navy SEALs: How to build a warrior mindset

SEAL training is the ultimate test of both mental and physical strength.

Scroll down to load more…
Quantcast