How do users use spatial memory?

Question

I have some questions about how spatial memory works and the effects on user interfaces:

• Do users seek items by spatial memory? What do they actually "link" to a position - a particular object ("View the Fizzwidget is rightmost")? A family of objects ("Fizzwidget links go on the right")? A class of objects ("There are hyperlinks on the right")?
• What sort of position details does the user remember? Position relative to other objects or some frame on the page? If that frame moves, how is the user's memory affected? If the position remembered is relative to the viewport entire, what happens when a window gets resized or stretched?
• What about positioning in webpages larger than the viewport? Do users visualize elements at the bottom of the 'hidden' page, or at a particular location on the monitor? Or do they not remember a whole field of objects, but a series of various impressions?
• Do users learn positioning rules ("Positive actions on the right, negative actions on the left")?
• Do other factors help users commit things to spatial memory? I'm told that strong gridlines can help, but does anything else?

Any links to papers and academic research would be really valuable, even if they only cover individual sub-questions.

Answer 1

As Ben has already commented, this is a very broad question and there is a lot of active research going into it at the moment. However there is a good understanding on a few of the points, so I'll try answer those.

Spacial memory is relative, meaning that people remember the position relative to some reference object or feature. The problem is that there is a lot of variation between people as to what they tend to choose as their reference feature. Some people tend to use the outer edge, while others think of a pattern of objects.

I have heard (although unverified) that if you place a prominent object in the middle of other less prominent objects, that the prominent object tends to be the reference point. Although I have not done any academic research on this, my experience has shown that it holds.