Sharp Brains: Brain Fitness and Cognitive Health News

Neuroplasticity, Brain Fitness and Cognitive Health News


Is your brain ready for Monday? Tease your mind with these four optical illusions


A great way to learn more about our brains and minds is to look at how we can trick them–that is, to see how we react to brain teasers and visu­al illu­sions.

Below are four fun opti­cal illu­sions that let us learn­ about our visu­al system…ready?

(answers and expla­na­tions at the bot­tom)


1. Are the two orange circles above of the same size?


2. Are there gray dots at the intersections of the white lines below?

herman grid illusion test



3. Does Lincoln’s face look normal?

upside down eye illusions test


4. Where is the baby?

baby illusion test




1. The Ebbinghaus Illusion

The two orange cir­cles are exact­ly the same size, even though the one on the left seems small­er. This size dis­tor­tion may be caused by the size of the sur­round­ing cir­cles and their dis­tance to the cen­ter cir­cle.


2. Hermann grid illusion

There are not gray dots in this grid. How­ev­er “ghost­like” gray blobs are per­ceived at the inter­sec­tions of the white lines. The gray dots dis­ap­pear when look­ing direct­ly at an inter­sec­tion.


3. Does Lincoln’s face look normal?

It seems nor­mal but now, look at it upright: Lin­col­n’s eyes do not look quite right!

This is how the orig­i­nal image looked like, if seen upright.

Some neu­rons in the brain seem to spe­cial­ize in pro­cess­ing faces. And faces are usu­al­ly seen upright. When pre­sent­ed upside down, the brain no longer rec­og­nizes a pic­ture of a face as a face but rather as an object — neu­rons pro­cess­ing objects are dif­fer­ent from those pro­cess­ing faces and not as spe­cial­ized in face recog­ni­tion. As a con­se­quence, they (we) do not respond to face dis­tor­tions as well. This explains why we miss the weird eyes when the face is invert­ed..


4. Where is the baby?

Anoth­er great exam­ple of an illu­so­ry con­tour. The baby’s head is on the left, the baby’s feet are against the trunk of the tree on the right..


–> To keep learn­ing about your brain and mind, check out these Top 25 Brain Teasers, Games and Illu­sions, for Teens and Adults of Any Age.

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As seen in The New York Times, The Wall Street Journal, BBC News, CNN, Reuters,  SharpBrains is an independent market research firm tracking how brain science can improve our health and our lives.

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