Does a more ergonomic and user friendly interface/device make the human brain work less? There was an interesting discussion on UX.StackExchange related to washing machines and their front windows. I was very surprised that it took me like 2 minutes or so to figure out why the washing machine has a window, but most of the answers or comments (including those with many votes) don't express the real reason, which would be similar to this:


  For front-loaders without viewing windows on the door, it is possible
  to accidentally pinch fabric between the door and the drum, resulting
  in tearing and damage to the pinched clothing during tumbling and
  spinning. - Wikipedia.


Question: Does a more ergonomic and user friendly interface make the human brain work less, or less intensive, so it can not see the initial purpose of an improvement made in a system or on one of its elements?
ISO 9241, a standard covering ergonomics of human-computer interaction, defines in its subsection 9241-110, "Dialogue Principles", that the interface in information systems should be (among other things):


suitable for the task
facilitate learning
conform with user expectations
describe its own purpose and functioning


You could translate all this to:


  Don't make the user think too hard about what he has to do


Shneiderman, in his "Eight Golden Rules of Interface Design" and Nielsen in his "10 Usability Heuristics of User Interface Design" (also on Wikipedia), make this even more explicit:


Shneiderman, Rule 8: Reduce short-term memory load
Nielsen, Heuristic 6: Recognition rather than recall


Reducing cognitive load is part of the industry definition of usability. By that definition a usable product "makes the human brain work less".



Sources:


ISO 9241-110:2006 http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=38009
Nielsen, J. (1994). Heuristic evaluation. In J. Nielsen &amp; R. L. Mack (Eds.), Usability Inspection Methods (pp. 25-64). New York: Wiley.
Shneiderman, B., &amp; Plaisant, C. (2010). Designing the User Interface: Strategies for Effective Human-Computer Interaction (5th ed.). Reading, MA: Addison-Wesley.