James E. Cutting has done a number of studies on this topic in the movie domain. Take a look at ["Shot Durations, Shot Classes, and the Increased Pace of Popular   Movies"][1] (Cutting, 2015):

>"The pace of popular movies has    increased and statements about  this trend can be found in both the popular media and   in  scholarly works (see, for example, Bordwell and Thompson 2004;  Bordwell,   Staiger, and Thompson 1985; Cutting, Brunick, DeLong, Iricinschi, and Candan 2011b; Salt 2006, 2009)"
>
>"...   shorter shot durations make for more cuts, which in turn make for   
more intensified demands on viewers’ attention."



More work can be found here:
http://people.psych.cornell.edu/~jec7/pictures_film.htm

  [1]: http://people.psych.cornell.edu/~jec7/pubs/cutting&candanProj15.pdf