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Vision
Richard Lee, 23 Nov 2018

The Art of Optical Illusions

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What happens when your brain can’t ‘connect the dots’? Maybe it just creates them instead…

What are optical illusions and how are they possible?

Illusions are phenomena that cause a distortion of the senses. In the case of optical illusions, your visual system is tricked into perceiving something that is slightly (or dramatically) different from the reality of the actual object or scene you are observing.

When humans look at the world, they see many different shapes, shades, lines, and forms, all of which must be processed through the eyes and interpreted by the brain. Over time, we automatically differentiate and categorize the objects we see to make the visual information useful for interaction with the physical world.

Optical illusions help guide research on the brain and visual system, but there’s still a lot to be determined. A number of psychological theories have been put forward to explain what’s happening. One theory claims the brain attempts to fill in the blanks when there is ambiguous or limited visual information, in order to see a (useful) familiar form. Another states that the brain must “predict the future” in order to compensate for a lag time between the eye and the brain (1/10 of a second). In doing this, humans can live and respond in the present, but the brain sometimes makes errors in interpretation.

History, art and magic

Illusion has played a large role in human history, especially in regards to art and science. Visual perception that the sun, planets, and stars all revolved around a stationary Earth, led to Ptolemy’s inaccurate geocentric model of the universe. It wasn’t until Copernicus applied precise geometric principles to his observations of a “moving sun” and a “stationary Earth” that the fallacy of the optical illusion was finally overcome (over 1,000 years later).

With the advent of perspective drawing techniques during the Renaissance Period, artists were finally able to add a perceivable third dimension to their two-dimensional paintings. Art was changed forever in the Western world, and now we get to enjoy the mind-bending delights of modern illustrators and painters, such as Robert Gonsalves:

The Art of Optical Illusions

To this day, optical illusions are even seen as a form of entertainment. Just ask Penn and Teller or David Blaine. Both, and a long list of other magicians before them, have made a career out of stirring a captive audience with elaborate optical illusions.

Intentional confusion

In nature, there’s a common optical illusion that conceals itself well—camouflage. In the animal kingdom, the optical illusions that make prey difficult to see (crypsis) or appear to be something else (mimesis), are essential to survival. The same concept was almost universally applied to military combat uniforms as weaponry advanced at the turn of the 20^th century—a very useful illusion to avoid casualties.

The Art of Optical Illusions

Finally, however surprising, even zebras make the camouflage list. Research suggests their “dazzle-pattern” leads to optical illusions that distort the perception of motion from predators during a chase. This disruptive camouflage allows some animals to unabashedly stand out.

If you’re having trouble seeing more than optical illusions, then use your VSP Individual Vision Plan to schedule an eye exam with your doctor. If you don’t have vision insurance, find out how VSP can help you save on your next eye exam and pair of glasses.