Use of Scale to Reveal Character Relationships
(source:  Brian Stonehill's Scale Homepage, from his course on scale relationships.  Pomona College. CA)


At the start of the  sequence , Kane appears to the viewer as much bigger then Jed.



Later in the sequence  Kane shrinks as Jed grows, accompanied by Jed's verbal assault on Kane.


 
 
 

In the next shot Kane, unable to stand up to the words he knows are true, retreats to the part of the screen where he will again appear larger and more powerful than Jed, perhaps showing the viewer that he feels he has lost control and must make a desperate attempt at salvaging any control he may have over the situation by regaining a position of power.




The sequence culminates with the point at which two men are equal sizes  perhaps implying that the two are equals after all. 

Kane as a character is oblivious to viewers and cameras, but Welles as an actor and a director is well aware of what he is doing and the effects it will have on the viewer and the film.