Scientific Logic?

In the print edition of the Telegraph today a short item notes that research shows commercial breaks make watching television more enjoyable.

Published in the Journal of Consumer Research, 'findings' showed that the break refreshed people's capacity to concentrate, According to Dr. Leif Nelson, University of California, viewers enjoyment diminished the longer they watched.

If this is true why does enjoyment not diminish when watching a film, either on dvd or in the cinema, and might not this have something to do with the Continuously Repugnant Abhorrent Programming that is featured on television?