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Overcoming the Perception Problem
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post Oct 8 2012, 19:21
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I've noticed an increase in forum debate about the validity of transferring the credibility of ABX from the physical domain to perception testing. I'm wondering if anyone has found a way past this issue?

The purpose of blind testing is to subtract subjectivity from the effect of - for instance - a drug trial: to assess a medication's impact on a subject's physiology with interference from their psychology. But what about when the purpose of a test is subjective perception? How do we then subtract the effect of the method to arrive at a meaningful outcome?

While we would like to remove expectation bias from the equation, if the conditions under which this is done also change the perceptive state of the listener, the test is invalidated as surely as they would be by tissue sample contamination.

Recent large scale public experiments by Lotto Labs (http://www.lottolab.org/) demonstrated that perception acuity is dramatically altered by test conditions: for instance, that time contraction/dilation effects are experienced when exposed to colour fields. In one experiment, two groups were asked to perform an identical fine-grained visual acuity test. One group was pre-emptively 'manipulated' by filling in a questionnaire designed to lower their self-esteem. This 'less confident' group consistently performed worse on the test that the unmanipulated one: their acuity was significantly impaired by a subtle psychological 'tweak' that wasn't even in effect during the test.

It seems undeniable that the much grosser differences between the mental states of sighted and 'blind' listening - considered generously - cast serious doubt on the results thus obtained.

The harder line is that blind perception tests are a fundamental misappropriation of methodology. In psychology it's axiomatic that for many experiments the subject must be unaware of the nature of the test (see Milgram). If a normalised state is not cunningly contrived, results are at best only indicative of what a subject thinks they should do; at worst, entirely invalid.

Probing hearing, the point is that a test must not change the mental state of the listener.

The contrast between outcomes of sighted and listening tests is as stark as those demonstrating suggestibility (see McGurk), but giving too much credence to such an intrinsically unsound experimental approach (not spotting this difficulty) does no favours to our credibility at all.

The only way past the dilemma seems to be direct mechanical examination of the mind during 'normal' listening to explore why the experiences of sighted and unsighted listening differ. This seems to be an interesting question.

In the meantime, the idea that - despite the method problem - results from blind ABX are valid is at least supported by the majority of data derived from home testing, Audio DiffMaker et al, so we needn't get hung up on it.
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AndyH-ha
post Oct 19 2012, 20:56
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I could be missing the point, or dozens of them, but it seems to me the hypothesis has been presented that the conditions necessary for proper DBT themselves alter perception in such a way as to strongly bias against what people are physically capable of sensing about the external world (i.e. that part not inside their head). The evidence for that hypothesis is that people regularly report perceptions that they are unable to repeat under DBT conditions.

We do know, because it has been demonstrated many times, that perception of signals which can be successfully and consistently identified by test subjects can be strongly overridden by an expectation introduced into the trials. Now subjects often report signals as being what they expect to hear, rather than what the signals really are, and even report the expected signal when they are led to believe they will receive it but have been given nothing.

These particular findings seems to present a case for being skeptical of claims made from sighted tests. The proposition here is that the expectations introduced in the tests are equivalent to the expectations introduced by really knowing which signal is been received. This proposition is at least somewhat supported by the fact that the expectation can be introduced by letting the subjects see what they believe are the sources of the signals (e.g. the cables, the amplifiers, the wine bottles) when the signals are actually from something else.

As far as I can see, the hypothesis that perception is really so much better and more pure outside of these restrictive test conditions is useless to science unless, and until, someone can think up a (repeatable) means to positively test it. Maybe the gods open deeper levels of perception to those filled with wine, love, and sympathy, and stop up the ears of those playing with that nasty science idea, but unless the gods decide to openly reveal themselves, we are unlikely to ever know. We can posit possibilities until the sun burns out but will never get any closer to knowing.
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Arnold B. Kruege...
post Oct 19 2012, 21:30
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QUOTE (AndyH-ha @ Oct 19 2012, 15:56) *
I could be missing the point, or dozens of them, but it seems to me the hypothesis has been presented that the conditions necessary for proper DBT themselves alter perception in such a way as to strongly bias against what people are physically capable of sensing about the external world (i.e. that part not inside their head). The evidence for that hypothesis is that people regularly report perceptions that they are unable to repeat under DBT conditions.

We do know, because it has been demonstrated many times, that perception of signals which can be successfully and consistently identified by test subjects can be strongly overridden by an expectation introduced into the trials. Now subjects often report signals as being what they expect to hear, rather than what the signals really are, and even report the expected signal when they are led to believe they will receive it but have been given nothing.

These particular findings seems to present a case for being skeptical of claims made from sighted tests.


You trying for a Master's standing in understatement of what should be obvious to anybody with real world experience? ;-)

People who ignore expectation bias, along with the other systematic biases that afflict most amateur listening tests are just showing what little they know about the real world.

The three biggies are matching levels, listening to exactly the same musical selections, and managing expectation bias. Most audiophile listening evaluations ignore all 3.

Given the endemic nature of this sort of ignorant and sometimes willfully irrational behavior, most of these discussions about the alleged failings of well-controlled subjective testing can be dismissed out of hand.

IME trying to teach audiophiles how to do reasonable subjective tests is like trying to teach pigs to fly in that the usual result of the latter is that you at minimum upset the emotional state of the pig. ;-)
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Posts in this topic
- item   Overcoming the Perception Problem   Oct 8 2012, 19:21
- - Soap   You appear to be confused. Despite common shortha...   Oct 8 2012, 19:38
- - item   To rephrase: what, in any trial, is blind testing ...   Oct 8 2012, 19:52
|- - Soap   QUOTE (item @ Oct 8 2012, 14:52) To rephr...   Oct 8 2012, 19:59
|- - item   QUOTE (Soap @ Oct 8 2012, 19:59) QUOTE (i...   Oct 8 2012, 23:32
|- - item   Part of Beau Lotto's 'Public Perception pr...   Oct 9 2012, 00:30
||- - Porcus   QUOTE (item @ Oct 9 2012, 01:30) Part of ...   Oct 9 2012, 10:53
||- - item   QUOTE (Porcus @ Oct 9 2012, 10:53) You ca...   Oct 9 2012, 12:23
||- - Porcus   QUOTE (item @ Oct 9 2012, 13:23) This for...   Oct 9 2012, 16:04
|- - krabapple   QUOTE (item @ Oct 8 2012, 18:32) Partly, ...   Oct 9 2012, 03:51
|- - item   QUOTE (item @ Oct 8 2012, 18:32) Although...   Oct 9 2012, 11:14
- - DVDdoug   I just don't see how making a good scientific ...   Oct 9 2012, 00:59
- - greynol   @item: Perhaps you could share with us a little ab...   Oct 9 2012, 04:54
|- - Porcus   QUOTE (greynol @ Oct 9 2012, 05:54) a fai...   Oct 9 2012, 09:57
|- - item   QUOTE (greynol @ Oct 9 2012, 04:54) @item...   Oct 9 2012, 11:42
|- - 2Bdecided   QUOTE (item @ Oct 9 2012, 11:42) Positive...   Oct 9 2012, 14:15
||- - item   QUOTE (2Bdecided @ Oct 9 2012, 14:15) QUO...   Oct 9 2012, 14:37
||- - 2Bdecided   QUOTE (item @ Oct 9 2012, 14:37) Deprived...   Oct 9 2012, 17:43
|||- - item   Sorry - been away, but lots of noise (most - fasci...   Oct 19 2012, 17:34
||- - dhromed   QUOTE (item @ Oct 9 2012, 15:37) 'Kno...   Oct 9 2012, 19:11
|- - greynol   QUOTE (item @ Oct 9 2012, 03:42) QUOTE (g...   Oct 9 2012, 22:07
|- - item   QUOTE (greynol @ Oct 9 2012, 22:07) @item...   Oct 19 2012, 18:33
- - hlloyge   The only people I know of to shun DBT method of te...   Oct 9 2012, 12:35
|- - item   QUOTE (hlloyge @ Oct 9 2012, 12:35) The o...   Oct 9 2012, 13:25
|- - hlloyge   QUOTE (item @ Oct 9 2012, 14:25) The sole...   Oct 9 2012, 13:54
||- - item   QUOTE (hlloyge @ Oct 9 2012, 13:54) The o...   Oct 9 2012, 14:09
|- - Canar   QUOTE (item @ Oct 9 2012, 05:25) I think ...   Oct 9 2012, 17:09
|- - krabapple   QUOTE (item @ Oct 9 2012, 08:25) The sole...   Oct 10 2012, 01:25
|- - item   QUOTE (krabapple @ Oct 10 2012, 01:25) QU...   Oct 19 2012, 18:45
|- - Porcus   QUOTE (item @ Oct 19 2012, 19:45) QUOTE (...   Oct 19 2012, 19:22
|- - 2Bdecided   QUOTE (item @ Oct 19 2012, 18:45) Certain...   Oct 22 2012, 12:53
- - aethelberht   What I can perhaps maybe possibly gather from your...   Oct 9 2012, 13:17
|- - item   QUOTE (aethelberht @ Oct 9 2012, 13:17) W...   Oct 9 2012, 14:01
|- - aethelberht   "A negative means - equally - either a) the t...   Oct 9 2012, 14:14
|- - Arnold B. Krueger   QUOTE (item @ Oct 9 2012, 09:01) DBT is d...   Oct 9 2012, 14:53
|- - hlloyge   QUOTE (item @ Oct 9 2012, 15:01) Abstract...   Oct 10 2012, 21:04
|- - Porcus   QUOTE (hlloyge @ Oct 10 2012, 22:04) If y...   Oct 11 2012, 14:20
|- - hlloyge   QUOTE (Porcus @ Oct 11 2012, 15:20) Ehem ...   Oct 12 2012, 14:26
|- - Porcus   QUOTE (hlloyge @ Oct 12 2012, 15:26) QUOT...   Oct 12 2012, 15:04
|- - hlloyge   QUOTE (Porcus @ Oct 12 2012, 16:04) Not n...   Oct 12 2012, 22:14
|- - greynol   QUOTE (hlloyge @ Oct 12 2012, 14:14) I am...   Oct 13 2012, 14:25
|- - hlloyge   QUOTE (greynol @ Oct 13 2012, 15:25) QUOT...   Oct 14 2012, 13:35
|- - Porcus   QUOTE (hlloyge @ Oct 14 2012, 14:35) Yes,...   Oct 14 2012, 23:31
|- - hlloyge   QUOTE (Porcus @ Oct 15 2012, 00:31) QUOTE...   Oct 16 2012, 09:54
- - Porcus   While I certainly agree that putting humans in a l...   Oct 10 2012, 13:09
- - 2Bdecided   It's like The Princess and the Pea. Audiophile...   Oct 11 2012, 11:58
- - skamp   If ABXing negatively alters one's ability to h...   Oct 11 2012, 14:28
|- - krabapple   QUOTE (skamp @ Oct 11 2012, 09:28) If ABX...   Oct 11 2012, 18:24
|- - mzil   QUOTE (krabapple @ Oct 11 2012, 13:24) QU...   Oct 15 2012, 17:14
|- - krabapple   You're right that different terms apply when w...   Oct 15 2012, 20:51
- - greynol   I believe our skeptic has flown the coop.   Oct 11 2012, 16:17
- - dhromed   Not everyone is as much a netizen as most of us. P...   Oct 11 2012, 17:05
- - googlebot   While the OP's reasoning and claimed inference...   Oct 11 2012, 21:44
|- - [JAZ]   QUOTE (googlebot @ Oct 11 2012, 22:44) Do...   Oct 11 2012, 22:37
||- - bandpass   QUOTE ([JAZ] @ Oct 11 2012, 22:37...   Oct 12 2012, 06:44
|- - sld   QUOTE (googlebot @ Oct 12 2012, 04:44) Lo...   Oct 12 2012, 03:38
|- - krabapple   QUOTE (googlebot @ Oct 11 2012, 16:44) Wh...   Oct 12 2012, 06:59
||- - googlebot   QUOTE (krabapple @ Oct 12 2012, 07:59) Ex...   Oct 12 2012, 21:44
||- - Nick.C   QUOTE (googlebot @ Oct 12 2012, 21:44) Th...   Oct 12 2012, 21:51
|||- - googlebot   QUOTE (Nick.C @ Oct 12 2012, 22:51) Is th...   Oct 12 2012, 21:58
|||- - Nick.C   QUOTE (googlebot @ Oct 12 2012, 21:58) Ye...   Oct 12 2012, 22:21
|||- - googlebot   I do not see how calling the phenomenon "prec...   Oct 12 2012, 23:43
||- - krabapple   QUOTE (googlebot @ Oct 12 2012, 16:44) QU...   Oct 13 2012, 22:05
|- - 2Bdecided   @Porcus: QUOTE (googlebot @ Oct 11 2012, 21...   Oct 12 2012, 10:08
|- - Arnold B. Krueger   QUOTE (googlebot @ Oct 11 2012, 16:44) Co...   Oct 16 2012, 15:51
- - greynol   I would be careful not to limit the word perceive....   Oct 11 2012, 22:58
- - greynol   I extract all the joy I could ever need from simpl...   Oct 12 2012, 06:11
- - Porcus   Among my friends, we have been blind testing ... h...   Oct 12 2012, 09:30
- - dhromed   But is there a problem?   Oct 12 2012, 22:12
- - AndyH-ha   The sighted test difference is not coming from the...   Oct 13 2012, 03:32
|- - greynol   QUOTE (AndyH-ha @ Oct 12 2012, 19:32...   Oct 13 2012, 14:16
- - Nick.C   @googlebot: You are now allowing the results to be...   Oct 13 2012, 09:43
- - 2Bdecided   I think Googlebot is making a valid philosophical ...   Oct 15 2012, 12:20
|- - pisymbol   QUOTE (2Bdecided @ Oct 15 2012, 07:20) I ...   Oct 15 2012, 13:48
- - skamp   QUOTE (mzil @ Oct 15 2012, 18:14) B. The ...   Oct 15 2012, 22:49
|- - krabapple   QUOTE (skamp @ Oct 15 2012, 17:49) What g...   Oct 16 2012, 03:58
- - greynol   There are ways of cheating to get positive ABX res...   Oct 15 2012, 22:57
- - mzil   [Trying to bring this back on topic] There is not...   Oct 16 2012, 04:32
|- - Woodinville   QUOTE (mzil @ Oct 15 2012, 20:32) [Trying...   Oct 16 2012, 04:33
|- - Porcus   QUOTE (mzil @ Oct 16 2012, 05:32) Here...   Oct 16 2012, 06:19
- - mzil   Please enlighten me. I am not a scientist nor have...   Oct 16 2012, 04:39
|- - krabapple   QUOTE (mzil @ Oct 15 2012, 23:39) Please ...   Oct 16 2012, 22:28
|- - mzil   QUOTE (krabapple @ Oct 16 2012, 17:28) QU...   Oct 17 2012, 00:30
|- - saratoga   QUOTE (mzil @ Oct 16 2012, 19:30) So even...   Oct 17 2012, 03:03
||- - mzil   QUOTE (saratoga @ Oct 16 2012, 22:03) QUO...   Oct 17 2012, 05:35
||- - saratoga   QUOTE (mzil @ Oct 17 2012, 00:35) Sorry, ...   Oct 17 2012, 05:43
|- - krabapple   QUOTE (mzil @ Oct 16 2012, 19:30) QUOTE (...   Oct 17 2012, 04:53
||- - mzil   QUOTE (krabapple @ Oct 16 2012, 23:53) QU...   Oct 17 2012, 06:36
||- - mzil   QUOTE (krabapple @ Oct 16 2012, 23:53) Do...   Oct 17 2012, 07:22
|||- - mzil   QUOTE (mzil @ Oct 17 2012, 02:22) QUOTE (...   Oct 18 2012, 19:16
||- - Arnold B. Krueger   QUOTE (krabapple @ Oct 16 2012, 23:53) Do...   Oct 18 2012, 14:04
|- - Porcus   QUOTE (mzil @ Oct 17 2012, 01:30) QUOTE R...   Oct 17 2012, 18:51
- - knutinh   Self-reporting about ones mental state surely carr...   Oct 16 2012, 21:02
- - greynol   Let me get this straight, the subconscious mind is...   Oct 17 2012, 05:28
- - mzil   Thanks, Porcus. I'll check it out.   Oct 17 2012, 20:14
- - krabapple   It's best to be careful drawing conclusions fr...   Oct 19 2012, 17:53
|- - 2Bdecided   QUOTE (krabapple @ Oct 19 2012, 17:53) It...   Oct 22 2012, 12:49
- - AndyH-ha   I could be missing the point, or dozens of them, b...   Oct 19 2012, 20:56
|- - Arnold B. Krueger   QUOTE (AndyH-ha @ Oct 19 2012, 15:56...   Oct 19 2012, 21:30
- - AndyH-ha   My point was not that many reported tests involve ...   Oct 19 2012, 22:31
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