However, the demonstration below is almost too good to be true. Is the dog like Clever Hans, picking up unconscious cuing, or is he indeed listening and converting the sounding pitches to key presses?
My prediction: the dog primarily watches the eyes and other body movements of the trainer, and does not really listen. A curtain between the owner and the dog would confirm this.
Update Summer 2013: See below for a composition by Brechtje van Dijk broadcasted by Vrije Geluiden in May 2013, with the same two dogs. Look closely: they look carefully, but do they listen?
* N.B. Relative pitch is far more special, see earlier blogs.
Levitin, D., & Rogers, S. (2005). Absolute pitch: perception, coding, and controversies Trends in Cognitive Sciences, 9 (1), 26-33 DOI: 10.1016/j.tics.2004.11.007