MRC01
Major Contributor
The fact that fast switching is necessary shows that audio memory captures a limited amount of detail, and those limits shrink quickly over time. Adding a delay as small as a few milliseconds measurably reduces test sensitivity, yet most people would say that a few milliseconds seems to qualify as "fast".... You're correct that lack of audio memory is a difficulty in these tests, but "fast switching" is a solution that works. If you can flip back and forth between two audio devices quickly in a blind test, people can identify even small audible differences.
Certainly, fast switching is better than slow switching. But how fast is fast enough? This leads one to wonder whether the Y-intercept of that function is zero, or slightly above zero. In other words, even an instantaneous switch still relies on memory, comparing what you are hearing now (perception) to what you were hearing before (memory).
For example, by contrast, tactile comparisons can be done entirely perceptually without requiring an act of memory. You can touch object A and B with different fingers or hands comparing them simultaneously.
I'm not suggesting that blind testing is not useful. Clearly, it is! And it may be the best tool that we have. But it has its limitations, meaning one can't assume the sensitivity of the test fully equals the sensitivity of perception. Blind testing reveals the sensitivity of perception that can be demonstrated through short-term memory with statistical significance, which may be slightly less sensitive than perception itself. The fact that such short delays do reduce sensitivity, suggests this may be the case.