Psyche 11[6] (2005)
Abstract
This demonstration recreates an example of introspective training from E.B. Titchener's laboratory manual of 1901-1905. The purpose is to prompt thought about the prospects of introspective training as a means of improving the quality of introspective reports about conscious experience. The demonstration requires speakers or headphones, and a high-speed internet connection is recommended.
Difference Tone Training (published version: August 11, 2005)
or if that link doesn't work, you can follow this link to the penultimate version, which is identical to the published version, except in formatting details:
Difference Tone Training (May 18, 2005)