snarlydwarf;180098 Wrote: > > Can't we all agree on some basic realities: > 1) Human perception is easily fooled by a variety of influences > (loouder, hints, expectations, etc... some obvious, some subtle) > 2) Removing as many external influences as possible is necessary to > do any scientific test (ie, in chemistry you record the room > temperature to make sure "the A/C was broken that day" is accounted > for). > 3) Admkitting that your mind is fallabile isn't an insult: everyone > has the same problem. It doesnt mean your ears arent golden either. > > This is why DBT is used for drug tests: because peoples expectations of > getting better corrupt the data. (It is scary how many placebos for > things like depression work...)
It goes way beyond perception being fooled. There is an infinite variety of stimuli in our environment that are acting on sensory receptors all the time. The only way to reduce the information to an amount that can be handled is through filtering the sensory information through pre-attentional and attentional processes before it even gets to the brain. There is a great deal of stimulation that triggers a sensory receptor that is never actually perceived in any meaningful sense. That's simply the nature of the process. It's not necessarily a matter of perception being fooled. Sensory discrimination is a learning process. Without the experience, there are discriminations that you cannot make. A oenophile can tell you in very great detail about wine from a single taste. I don't like wine, and would have a hard time telling a classic wine from a $5 bottle. I haven't had the training, and cannot make the taste discrimination. We are hardwired so that we do NOT experience any sensory stimuli without preprocessing. What gets to the brain in not a veridical representation of what we see, hear, smell, taste or touch. To give you a very common example: <---> >---< We know that both lines are the same length. However, the cues i the lines tell us the bottom line is longer, so that's how we perceive it. (Note, the breaks between the dashes make it easier to see past the illusion). In any event, we have all seen optical illusions. They occur due to "shortcuts" in the perceptual process that simplify perception. This occurs in audition also. In removing external influences, you also need to insure that you are not removing influences that affect the experiment. In a chemistry experiment, you record room temperature. If temperature affects the reaction, you can at least account for a negative result. The open question is whether or not DBT itself influences the ability to make the discrimination at hand. Bear in mind that the senses do not operate independently, particularly once you get to the attentional level. It is absolutely essential in a DBT to have a positive control, where known measurable and audible differences are part of the test. If you don't prove that the test is not reducing the ability to affect a known difference, you cannot even begin to say what a negative result on an unknown difference means. Placebo's do work...both ways. Expectancy can eliminate a real difference as easily as it can produce a false positive. I have used DBT in pharmacology. I don't trust results without it. However, I also take a great deal of care to insure that I've got a reasonable chance to interpret a negative result, or I'd never get a study approved by an IACUC or an IRB. That includes running power analyses to insure that I've got an adequate N to interpret a negative result, as well as running appropriate controls to insure the sensitivity of my test procedures. There are also times when a DBT cannot be run in pharmacology (for example, the test drug produces unique side effects that may not be harmful, but are easily distinguished from a placebo). So, we use alternative methodologies, simply because the circumstances of the experiment indicate that DBT is not the right tool for that particular compound. As Mr. Natural said to Flakey Foont long ago: "Use the right tool for the job!" -- hirsch ------------------------------------------------------------------------ hirsch's Profile: http://forums.slimdevices.com/member.php?userid=7288 View this thread: http://forums.slimdevices.com/showthread.php?t=32352 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
