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In Reply to: Re: HDMI cables - anyone notice differences in picture quality between brands? PC World say otherwise. posted by Estes on November 8, 2006 at 16:22:24:
and sound has greater resolution. you may not be able to perceive differences in visual reproduction between 2 hdmi cables, but you can definitely detect sonic differences arising from different makes and cable directionality. play a cd through the hdmi cables. pick the one that sound better. chances are visually it would be better too, but it will be difficult to verify since most people won't have 2 screens side by side and we still don't have a playback source with 2 hdmi outputs. incidently, it also implies that we have less visual memory retention ability than audio.
Follow Ups:
I fear audiophiles often imagine their audio memory to be greater than it is, so they claim to hear differences they could not discriminate in a forced choice test, e.g., ABX where you need to be able to reliably say whether X is A or B. So audiophiles dismiss such tests out of hand.
We don't want to get into the whole DBT debate (I hope???), but quite often it's the case that we can't pick out differences in short term tests, when over the long term it's obvious that 'A' is fatiguing while 'B' is more involving.
Best Regards,
Chris redmond.
The one thing that the boosters of double blind tests overlook, is that they are asking the wrong question. The boosters ask, can you tell the cables apart? The question should be, WHICH do you LIKE better.Double blind drug trials are not run asking patients to identify which SSRI they are on, nor are they asked if the pick the placebo from the real anti-depressant. They are asked, Do you feel better?
Estes,If you can't tell one from another, how are you supposed to tell which you like better? It is circular.
A double blind trial that asks a patient if he feels better can be a valid forced choice procedure. If patients are just as likely to say they feel better after receiving a placebo, you can conclude the treatment is not efficacious; OTOH, if patients reliably feel better after taking the treatment, you can conclude it is efficacious. Of course, in a double blind test neither the giver nor receiver know in advance whether the treatment or placebo was given.
Regrading an earlier poster who posits fatigue as a dependant variable, that is a complex, ill defined variable too subject to confounding to be reliable.
The point I am making is you don't ask the PATIENTS which medication they are on. That is why it is not circular. The main researcher knows of course, as he/she is the one keeping track.Clearly, you record who gets what, in a fashion so that no one knows what they are on, just as you describe. You ask the patients "how do you feel", NOT can you tell which medication are you on.
The number of "feel better", side effects and so forth are tabulated, run through a statisical analysis to determine if the medication is, in fact, effective. There are patients who say the medication has no effect, just as there are others who say the placebo works great. The question then becomes are these rates difference from chance, as determined by statistical analysis.
Back to my point, in a blind test of equipment, you should be asking the participants, which sound do you like better, not can you tell wire A from wire B.
Estes,I'm not sure why you can't understand that your reasoning is circular, but I don't think it's worth beating on any more. Early in my career I designed and anlayzed many experiments. That was one of my strong suits, because I was more interested in that than human auditory perception, even though my post doctoral work centered on binaural processing. I'm afraid I was more interested in the methodology than the substance. When I got a DEC PDP-11 with 8 kBytes of memory! to control my lab, all else flew out the window. At the Acoustical Society meetings the old guys used to complain that all the kids talked about was their computers.
You're not related to the famous Bill Estes fron Stanford are you?
Maybe I am mistaken. But I can't help but feel you are missing my point. In a drug trial for example, it does not matter what the participants guess they are on (guess, because in a DBT, they don't know what they are on), but the statistical rates of improvement. So the question asked is, do you feel better? (in a general sense). By extension, we should ask, which picture LOOKS better. But as you said, enough.We could into a discussion on the value of computers...the cognitive science guys are really into computers & seem to ignore that there is a biological substrate (ie. a brain & nervous system). So I am with the old guys ;-)
To answer your question, no not Bill from Stanford. However, I should say nearly all of my research has been clinically focussed. In fact, during the dissertation defense the first comment from my external was, "clearly you are a clinican". That has been my focus since that time, as I find the whole publication process, needlessly nasty.
My buddy, who is a fellow of the APA, still gets nasty replies to his papers from "blind reviewers". He has been at it long enough (& has enough status) to be able to say that the reviewer or editor are "inexperienced". His response to reviewers who say sections are not well written, is also worth a laugh. He says, "I can see how this reviewer may have misunderstood what I was writing about."
I will take this opportunity to thank him again for helping through the thesis process. Don, has the ability to summerize the ramblings of a "student" & put it into context, very helpful as you wade through tons of papers. His help with the stats was also greatly apperciated.
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