What are some popular optical illusions and how do they work?

[Ivan Seeking]

http://www.eyetricks.com/fcount.htm

 

[Smurf]

I've seen this before, good trick.

 

[Galileo]

I missed 3 of them.

There was a show on tv awhile ago which demonstrated how easily you can overlook things if you are concentrating on something else.

They played a video showing people (about 10) running around and throwing the ball at each other. Half of them had white shirts, the other half blue and you had to carefully count the number of times the ball was tossed.

Halfway the film there was apparently a big guy in a big monkey costume walking between the players. It totally did not see him (which was the idea).
Ofcourse I saw the monkey in the replay, it was filling the space of 3 persons and was even waving at me. Amazing.

 

[gnome]

Most people miss the f's in of? Why? Where's the optical illusion? If you're counting f's, what else are you concentrating on besides f's?

I was about to answer 6 but just before clicking the button I realized (since I was looking for a trick) that the "puzzle" didn't ask how many f's there are, it asks how many F's. There's only 1 of them.

 

[drunkenfool]

Most people miss the f's in of? Why? Where's the optical illusion? If you're counting f's, what else are you concentrating on besides f's?

Exactly my thoughts. However, I've tested this on a few people and most of them don't count f's the way we do. Weird...

 

[gnome]

Originally posted by drunkenfool:
I've tested this on a few people and most of them don't count f's the way we do.

I'm sure that was a suitably controlled experiment, right?

Was there any correlation between the number of f's found and the quantity of beer consumed?

 

[Gonzolo]

I think it either has something to do with the word "of" not being a noun, verb or adjective, small, and common, or the "f" sounding live "v".

I counted 6 this time but only 3 when I first saw the sentence about 10 years ago.

 

[Moonbear]

I guess I've trained myself to proofread well. I found all 6 the first time through. Expecting there must be a trick of some sort, I went back through two more times to make sure I didn't miss an F. They actually made it pretty easy to find f's though. Aside from the first few words, the rest of the words are lacking in tall letters other than f's, so you don't have to read them at all, just skim the tops of words for the f's sticking up above the other letters.

 

[Gokul43201]

Yeah, this was pretty surprising to me - that people would miss the f's in 'of' !

It's easier to screw misread something like :

How much wood would a woodchuck chuck if
if a woodchuck would chuck wood ?

 

[Greg Bernhardt]

This is one of the best I've seen, check out the video link in the middle of the page

http://www.grand-illusions.com/dragon.htm

 

[Smurf]

that is absolutely amazing.

 

[Greg Bernhardt]

Here is another fun one I just found:
http://www.patmedia.net/marklevinson/cool/cool_illusion.html

 

[matthyaouw]

That dragon is incredible. I'm printing one off, but it probably won't work as well as that one.

 

[matthyaouw]

Done! It works, but only if you have one eye closed, otherwise depth perception interferes and it doesn't work. This thing is so cool.

 

[matthyaouw]

Another:

Look at the two pictures- angry man on the left and calm woman on the right. Get up and take a few steps backwards, then look again.
http://www.ianrowland.com/MiscPages/Mrangryandmrscalm.html

 

[mattmns]

Hmm, I counted 6. For the angry man I could not see it when I took a few steps back

 

[DaveC426913]

I think the designer of eyetricks.com needs to make the Next button more prominent. I almost missed it.

 

[DaveC426913]

My favourite mind trick

https://www.physicsforums.com/showthread.php?t=98645"