Perception

Perception again, yes. Like I said, I think it is an interesting subject. Consider the following item:

We have four frigidaires, all of them are white.
Now answer the following questions:
What is the colour of the first frigidaire? ...
Yes, that is correct.
What is the colour of the second frigidaire? ...
Indeed, that is correct again.
Now can you tell me the colour of the third frigidaire? ...
Well, correct again. We're nearly there.
Tell me, what is the colour of the fourth frigidaire? ...
Correct, that was easy.
Now tell me, what does a cow drink? ...

Okay, if you say so....

I am not sure as how this works written as well, but if it didn't then try it with somebody. Just ask the questions, wait for the answer, then ask the next question.
This is an example of "priming".

Another example, answer the next questions:
"May a woman marry the friend of her daughter?" ... "May a man marry the mother of his sister?" ... "May a man marry the sister of his widow?" ...
Guesses are that about eighty percent of the people will say 'yes' to the last question. The right answer, of course, should be 'no'.
(If you don't see it, ask yourself: what does 'widow' say about him?).

It is interesting to see what goes wrong here. Apparently our minds get set on a track and then it is difficult to change. It illustrates that we only use a part of the information that we get.
But even if we only use a part of all the available information things can go wrong. Read the following words:

That was not too hard, was it? Just a few names of colors. Piece of cake.
Now look again, but now do not read the names, but name the colors you actually see, the colors of the words.
Maybe still a piece of cake, but quite a different cake, is it not? It should not be too hard, but it is.

This is an example of conflicting information. It should not be any problem if the words were f.e. Icelandic, or in Japanese characters (unless you were from Iceland, resp. Japan, of course). Young children who still have to learn to read, but already know their colors do not see any problem.
We get two sets of information: (1) the color and (2) the text. When those two match there is no problem, but when they don't...
This effect is called "the Stroop-effect", named after Dr. John Ridley Stroop who did describe the effect first in 1935.

Want to try some more 'stroop'?
go http://www.dcity.org/braingames/stroop/
When you like those braingames, have a good intuition, and an understanding of statistics I suggest to play the "3-doors game".

More about priming?
Priming: Priming is an acuteness to stimuli because of exposure to a certain event or experience. For example, an individual who has just purchased a new car may now start to notice with more frequency other people driving her same make and model. This person has been primed to recognize more readily a car like hers because of the experience she has driving and owning one.(http://www.alleydog.com/glossary/definition.cfm?term=Priming)
wikipedia
the priming theory
Want to try an experiment?