Hering Illusion

Estimation 20 March 2012 0 Comments

Hering Illusion

Do the red lines below appear to bow outward?  Or are they parallel? The red lines are straight and parallel and do not bow outward despite their appearance.  This illusion, known as the Hering illusion, was discovered in 1861 by a German physiologist named Ewald Hering.  The Hering illusion produces the opposite effect of the […]

Wundt Illusion

Estimation 19 March 2012 0 Comments

Wundt Illusion

Do the red bars appear perfectly straight and parallel? The lines are straight and parallel.  Some viewers will perceive the lines to bow inwards due to the angles of the blue lines.  This illusion was first observed by German psychologist Wilhelm Wundt during the 19th century.  The Wundt illusion produces the opposite effect of the […]

Müller-Lyer Illusion

Estimation 16 March 2012 0 Comments

Müller-Lyer Illusion

These three horizontal lines are all the same length.  Does the middle line appear to be longer than the top line? The arrows on the end of the lines give the impression that the lines are different lengths.  The red horizontal lines help to show that they are all equal.  This is known as the […]

Orbison Illusion

Estimation 14 March 2012 0 Comments

Orbison Illusion

In 1939, William Orbison described the following illusion where the red square appears to be distorted by the presence of the angled blue lines. It does not look to be a perfect square, but if you take a sheet of paper or something else with a straight edge and line it up, you will see […]

Zöllner Illusion

Estimation 12 March 2012 0 Comments

Zollner Illusion

Do the black lines presented below appear to be parallel? The black lines are indeed parallel even though they do not appear to be.  In 1860, this classic optical illusion was discovered by Johann Karl Friedrich Zöllner.  This illusion was the basis for the discovery of the Poggendorff illusion.