Qualia8,
"Far from cleansing the auditory taste of one note from one's mind and then playing another, you need to play them immediately back to back for comparison purposes. Perhaps you can switch the order around to eliminate after-effects"
Switching the order around doesn't eliminate after-effects, it only replaces one "smeared" event by another; possibly different from the first. For example, if you follow a yellow image by a red one, the complementary after-image of yellow (violet) will "combine" with red. If you switch the order and show red first, followed by yellow, then the complementary after-image of red (green) will "combine" with yellow.
Best Regards, John |
Hi Pabelson,
"But they've also discovered that, once you've learned those differences, the best way to confirm that those differences are really there is through short-term listening tests that allow you to switch quickly between the two components."
Any neuroscientist who would claim he/she discovered "the best way" to confirm differences would not be very credible with me on at least two counts. First, it is the "best" amongst which collection of methods? Have ALL POSSIBLE methods been tested? Perhaps some heretofore untested method could be even better. So, the scientist overstated the result. Although such hyping occurs, it is hardly scientific. It would also lead me to question if the scientist's methods also lacked precision and other high scientific standards.
Second, to determine that this method is the "best", it must be different from the rest. But how can the neuroscientist determine this difference? By DBT, the "best" method that determines differences??? But then the neuroscientist will be using the very method he/she is attempting to validate. In other words, the neuroscientist would hang himself/herself in a logical loop of circular reasoning.
Your statement appears to be based, at least in part, on faith in neuroscience and psycho-acoustics. These are important sciences but they are not hard sciences like physics and chemistry. Compared to physics, they are sciences in infancy. Their levels of rigor, accuracy, predictability, and reliability are not yet in the same league as those for physics and chemistry. So, my level of confidence in them is not as great as what yours appears to be in your posts. It's the complexity.
The complex substratum involved in auditory perception is not yet sufficiently understood to shed light on the finer aspects. A large number of neurons form millions of possible pathways that a particular "encoded song" can travel in our brains to yield the perception of its sound and our reaction to it. The same song or piece of music produced by the same audio system a few moments later may not travel the exact same pathways in our brain and hence may produce a different experience. This variability is compounded by the non-constant chemical environment that influences our experience. (For example, the amount of endorphins available at any one time.) Emotional changes, expectations, suggestions, levels of alertness, fleeting nature of memory, etc. add to the variability. Also, the brain circuitry is not as rigidly set as it once was thought to be. It can change with experience and learning. At the current state of neuroscience, there is insufficient organization, understanding and integration of this variabile milieu to shed light on the finer issues about DBT. That may be reason enough for some opponents of DBT to claim that "to DBT or not to DBT" is an irrelevant question. I, for one, am in favor of rigorous DBT and would find the positive results useful but the negative results inconclusive for reasons given in my previous post.
Best Regards, John |
For the record, I am not opposed to rigorous DB tests; they can provide useful information. However, I do NOT have a high level of confidence in definitive interpretations of a negative result of a short-term DBT involving 2 components that may have subtle differences. As noted in my previous posts, the underlying complexity has not been unravelled yet.
I'll try one last time to hint at the complexity involved. In wine tasting, if you taste two samples one after the other, you should rinse the mouth with water to minimize the influence of the "after taste" of the first sample on the second one. If you look at a bright yellow object and then close your eyes, you will see an "after image" of a complementary color. As long as that "after image" persists, it is a "noise" that may influence some subtle subsequent visual experiences. Our brain circuitry and chemistry is not like electronic circuitry. I does not start and stop with the stimulus; and it has it's own variable "noise floor". The "after effect" that persists may mix with the subsequent stimuli. This added "noise" may smear the more subtle characteristics. A SHORT-TERM DBT may not allow enough time for the "after effect" of the previous sample to subside. That "noise" in the neuro-biological environment may smear SUBTLE differences.
Those of you with high level of confidence or faith in the negative results of short-term DBTs have yet to address this and other complexity issues. Hopefully, these issues will be sufficiently addressed as neuroscience and psychoacoustics develop. The reason why tremendous amount of research is still going on is because there is a lot that is not yet known. At least not enough is known for me to be very confident.
In the meantime, a rigorous DBT, among other things, should: 1)provide sufficient time between samples; 2) reduce the room effect that may smear differences; 3) make sure the participants pass a comprehensive hearing test, demonstrating that they can hear the frequencies in the audible range and can percieve dynamic gradations; 4) make sure the tested material includes a full spectrum of frequencies and a large variety of harmonic textures and dynamic shadings; 5) adjust the level of sound, preferably without adding any other components into the signal path that may smear differences; etc. After all, a meta-statistical analysis on a lot of flawed DBTs is not good science. |
Hi Phredd2,
You asked for some additional elements for rigorous methodology. In addition to the acuity tests I mentioned previously, participants should pass reasonable memory tests. Otherwise, their inability to distinguish 2 amps may not be a statement about the amps but about the participants. It is fine with me if an audiophile wants to listen privately just to see if he/she likes or prefers a component. But this is not acceptable for rigorous testing. Therefore, participants should be able to demonstrate their critical listening skills. If they aren't accustomed to listening consciously for nuances in harmonic textures, changes in micro-dynamics, phrasings, ambience, decay, etc., then they may miss subtle differences in how 2 amps reproduce the different musical elements.
"After-effects", as pointed out in my previous posts, are inherent to our perceptual mechanisms and brain circuitry/chemistry and may smear differences between 2 components in a short-term DBT. Consequently, a negative result of a short-term DBT may have an interpretation other than "no difference in the amps". Allowing enough time for the "after-effects" to subside, is one way to reduce their effects. However, this may add to some degradation of memory, as pointed out in one of the posts above; but that just re-inforces my contention that the underlying complexity has not been unravelled enough yet to make definite determinations. Please see my exchanges with Qualia8 for additional comments.
Great Listening, John |
Hi Pabelson,
You did not address some critical issues I raised in my posts. In particular, that the "after effects" of sensory experience can combine with subsequent stimuli to smear differences. The "after effects" result when the brain circuits don't start and stop with the the stimuli. If you continue to evade by brushing aside the issues, then there is no reason for me to continue with this thread.
Best Regards, John |
With apologies to Shakespeare and all logicians: "To DBT or not to DBT is or is not the question."
Hi Pabelson,
Your quote points us to the central point of this discussion: "Yes, beauty can grow on you. But notice that it's not the lady who's changing. It's you. What does that tell us about long-term comparisons?"
It tells us what neuroscience has discovered. The brain is much more plastic than once believed. It is not static like electronic circuits. The brain circuitry and its chemistry change. New interneuronal connections are formed and concentrations of neurotransmitters and other brain chemicals change. So, what the brain could not distinguish one day, it may LEARN to distinguish in subsequent exposures to the experience. We have experienced this learning phenomenon as students, as professors, and as audiophiles. This is part of our growth and evolution. A double-blind test based on short-term listening sessions may not allow enough time for the brain circuitry and chemistry to reconfigure itself to discern the difference. Therefore, if a short-term double-blind test does not show a difference between two amps, it would not be correct to conclude that there was no difference between the amps, only that that particular test did not reveal a statistically significant difference. A double-blind test showing a positive difference may be useful for audiophiles, while the test showing no difference is an inconclusive statement about the amps.
Incorrect interpretations can also be made for long-term double-blind tests. History of science shows us that even the hard sciences like physics are not immune from making incorrect interpretations. A committment to truth and critical thinking helps purify science to better the human condition. Otherwise, our implicit assumptions may yield tautological statements similar to the very first statement in this post. Although it is logically valid, it does not contain useful information for the audiophiles.
Best Regards, John |
Qualia8,
There is a vast array of specializations among the neurons in the brain. Some, as you pointed out, detect differences, others sameness; yet others, change or motion or timing, etc. Ignoring that complexity, may lead both sides of this discussion to over-simplification at best and to closed-mindedness at worst.
With that in mind, let me add the flip side to my previous post to you. The after-effects may not only smear differences, but they may also distort sameness. Take for example the two abstract amorphous paintings containing a rich array of colors in my living room. Everyone who looks at either one, reports the same phenomena. The colors change, the amorphous shapes change and those shapes move. Now, we know the painting remains the same. The changes are the result of the brain's processing. It appears the after-images of the various colors "combine" with the direct stimuli to produce a change in the perception, which in turn forms it's after-images which "combine" with the subsequent direct stimuli, etc. What follows is a sequence of illusory changes which create a dynamic that is not there.
This perceptual phenomena of after-images has been studied but it has not been eliminated. The temptation to reduce it's effect by taking micro-second intervals of music, automatically prejudices the methodology against percieving differences that require longer intervals; for example, decay and rhythm.
The debate with probably go on. In the meantime, it's good to have a discussion that produces more illumination than heat.
Enjoy the Music, John |