Just read that people don't like watching talking heads...or rather when watching talking heads people soon get bored...most will start to ignore after 22 seconds. Actually I have read that people get "fatigued" with an image on screen after 7 seconds.
Warhol did a series of short films that were just shots of people's faces. I think they lasted around 3 minutes each (which is the time contained in a 100 foot 16mm film roll). These are facinating and lovely "portraits."
I don't really adhere to the quick change image rule and I think we are making people less likely to really look based on constant image change. HOWEVER the 22 seconds should be a rule to those who think that just by virtue of the camera turned on them, they are facinating. It is a subtle line between what is interesting and what is cause for wandering eyes. Sometimes this is purely based on the viewer. Sometimes it is just us.
