How optical illusions trick your brain

The connections between neurons in the retina, specifically the connections referred to as “lateral inhibition,” help us see which of the following better?

• Contrast

• Faces

• Colors

Improving the contrast of an image (making the dark regions darker and the light regions lighter) helps us to identify:

• The edges of objects

• The center of objects

• The color of an object

What assumption does our visual system make in order to see curved surfaces (domes, holes)?

• Light comes from above

• Curved surfaces are always evenly lit

• Curved surfaces are always easy to see, no assumptions are made

Which part of the face does our brain pay the most attention to?

• Eyes and mouth

• Eyes and ears

• Eyes and chin

If all these assumptions sometimes lead to mistakes, for example in these optical illusions, why do we make them?

• 
  It helps us see things faster

• It helps us see things correctly

• It helps us pay attention to what's important

• All of the above

Humans rely heavily on light and our sense of vision to see the things around us. Which animals use a completely different sense (other than vision) to see the things around them?