I will explain these operations from the psychological model, because I believe, rightly or wrongly, that this is the most widely accessable perspective to my readers.
I may not be your average reader, but for some feedback, I hail from the information model. :)
Great! I tend to prefer that one also. But I also figured those of us that understand the information model are likely to be okay with psychological model explanations, whilst the reverse may not hold true... ;)
I know what you mean. :)