What Is the Psi Phenomena or Psi Effect in Psychology?

[help1please]

Homework Statement

My problem is that I can't remember a certain psychological effect.

Homework Equations

N/A

The Attempt at a Solution

I remember reading up a certain phenomenon, or effect of brain. The brain when viewing an image becomes ''imprinted'' into the mind. When that specific image no longer exists, the image may continue to be imprinted in the mind, for many seconds at a time.

I believe it is called the psi phenomena, or psi effect or something along those lines. Does anyone know what I am talking about, finding it difficult finding any related topics on the net to clarify this for me.

 

[help1please]

It's ok, I finally found a related article on it http://askville.amazon.com/close-eyes-negative-image/AnswerViewer.do?requestId=7105127 though no mention of the psi effect as its name... it's called an afterimage.

 

[chemisttree]

I was going to call it 'persistence of vision' but that is obviously wrong!

Were you remembering the 'phi phenomenon'?