Q 01/05

A 2015 viral photo split viewers over whether a dress was white and gold or which other pair of colours?

A) Red and green

B) Blue and black

C) Pink and grey

D) Purple and silver

Answer · why

B) Blue and black

Blue and black was the real dress, yet the washed-out photo made many people see white and gold; a 2015 survey found that answer was more common among...

Q 02/05

Which class of illusion is thought to come from overstimulating the eyes or brain, like the spots left by a camera flash?

A) Cognitive

B) Pathological

C) Physiological

D) Ambiguous

Answer · why

C) Physiological

Physiological illusions are thought to come from excessive or repetitive stimulation of one neural channel early in visual processing, which leaves an...

Q 03/05

Impossible objects like the Penrose triangle are which kind of cognitive illusion?

A) Ambiguities

B) Distortions

C) Paradoxes

D) Fictions

Answer · why

C) Paradoxes

Paradoxes are pictures of objects that could never exist: each corner of the drawing makes sense by itself, but the eye cannot join them into one soli...

Q 04/05

A stick appearing bent in water is the classic example of which class of illusion?

A) Pathological

B) Cognitive

C) Physical

D) Fictional

Answer · why

C) Physical

The bent stick is a physical illusion: it comes from light itself, which changes direction as it leaves the water before it ever reaches the eye, not ...

Q 05/05

Rubin's famous reversible figure can be seen as two faces in profile or as which object between them?

A) A bell

B) A key

C) A vase

D) A tree

Answer · why

C) A vase

A vase: Danish psychologist Edgar Rubin published the figure in 1915 to show that the brain must pick one shape as the object and treat the rest as ba...