Originally posted by alfagal:
[b]SPECIAL MYSTERY QUESTION
Why do we perceive an apple as red even under yellow light?
Why does that piece of paper still appears white although you are
in a dimly lighted room?
Sometimes when we go shopping, we enter certain shops that have
special coloured lightings. Why does that piece of clothing still
looks like green under bluish lighting?
Both the eye and brain are involved
What is the name of this phenomenon. Why does this happen?
CLUE: C _ _ _ _ _ constancy
Sorry, edited..[/b]
This one is a little tough... 
