by vysarge » Sun Dec 30, 2012 7:57 am
Hello ssyu!
I did a few quick searches- it's talking about a 'visual search', which is really more related to psychology than to computer science.
The idea is that the brain filters objects based on criteria- for example, if the task is to spot a green square in a grid of yellow triangles, the brain might look for green objects. However, if the task is to find a green square in a grid of green triangles and yellow squares, it isn't so simple. The brain might have to look for green objects first, then look through those for a square. Since it has to do more searches, and search more objects, the second task would tend to take longer.
There are apparently a few different theories on how it actually works, though, so I'd recommend searching "visual search" or "psychology visual search" online and finding a few good, understandable sites.
Hope this helped, and if you have any other questions, just ask!
-Vysarge
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Nature uses only the longest threads to weave her patterns, so that each small piece of her fabric reveals the organization of the entire tapestry.
-Richard Feynman