It's very important to provide the user with a good conceptual model. This makes it easier for the user to understand what's going on and to invent new actions from the older ones that work. But if you're not careful, if you give the wrong conceptual model, well, they'll invent wrong actions.
Here's an example. On the desktop model, we show each directory by an icon, an icon of a file folder. The icons are within the window. A number of years ago, when the Macintosh computer was first introduced, and all we had were floppy disks, my son was using the Macintosh. Its directory folder looked something like this. When he tried to save a file, he was told at one point "I'm sorry, there's not enough room to save your file." So, my son, being very intelligent, believed in the conceptual model that had been presented to him, went back, looked at the directory folder, and carefully moved all the file folders over to the left, making considerable room on the right. Then he went back to the same application and tried to save. "Can't do it," he was told. "No room." Why not? Look at the screen. There is plenty of room. Problem is, that's a wrong conceptual model. Room in the picture on the screen is not the same as room on the floppy disk.
なんとなくトランスクリプトをアップしてみたり．動画は The Voyager Company が 1994年につくった CD-ROM に収録されていたものだそうで．（ソース：”Videos from Design of Everyday Things"）
追記：twitter にて，koda_TO さんと t_hayashi さんにいっぱい添削していただきました．感謝．