can faceted search overload users?

For a while now, its been a concern for mSpace that we have been classified as good for intermedia/expert users, when lots of our work has focussed on making searching easier for people. We showed that the spatial layout was good for elderly people whose working memory was less capable at remembering things as other brosers change their layouts over time. Having said that, we too have watched participants of userstudies experience a moment when they first see the interface, with not knowing where to start.

An approach taken by other faceted browsers, such as the one provided by Endeca, is to change the layout a lot, but by taking away the decisions that people have made, so that all they have to do is look at the most important factors remaining. It's the same policy that google have - keep the options and ui as simple and clear as possible.

I've been seeking a way of finding out once and for all if there is a measurable aspect of UIs that we can use to prove that one way is better than the other. or that there is no difference at all. Certianly in mSpace we have shown that any overload experienced at first soon expire, and users have a real rich experience during search. Can mSpace be redesigned slightly to remove this initial wall and still give them the added richness of interaction that we have been striving to improve over the years.

Excitedly, i read a paper on cognitive load theory this morning on the train, which talks about what aspects of computer interfaces might make it harder for people to find and learn from information. I think this may hold the answer I have been looking for. It has measures and terms within the cognitive load theory for the effect caused by having duplicate, or redundant, or combined sources of information, on peoples ability to clearly and easily use a UI. I'm going to try running some numbers to see if any significant differences in the approaches taken to faceted browsing that might reveal why mspace is deemed intermediate/expert, and the approaches used by websites like walmart and diy.com are deemed simple for novices.