Placebo effect works like a charm when sighted listening comparisons are done.
I'd be wary of using the word 'gullible', it's a little adversarial. You have to bear in mind that the vast majority of people are unaware of how our perception works.
Pretty much any crazy tweak has the possibility to create a placebo effect. If you hear it then why would you doubt yourself?
For my own part I had a long period of being unhappy with the sound quality of my system and replaced equipment, cables, and tried all sorts of daft things. Each time I changed something I perceived that the problem was solved and spent the next couple of hours listening happily.
Then next day I would come to listen to my now sorted system and realise that nothing had changed and the problem persisted.
That went on for a long time before it clicked with me that I was just experiencing the placebo effect over and over. But the reason I became aware of it was because I had a problem to solve. Now if you take someone who already has a fine sounding system and just wants to get an incremental improvement, they don't have that flaw to recognise. They add the snake-oil product to their already wonderful sounding system and placebo makes it sound even better.
Next day when they listen again it still sounds wonderful - because it always did! Consequently they do not receive any prompt that the snake oil product in fact did nothing. You have to cut people some slack with these things.
Hi folks the "Placebo Effect", is when a Placebo has an actual effect, not an imagined effect.
I see this term commonly misused on ASR.
If there indeed was a placebo effect, the sound would actually be changed for the worse or better not imagined to be different. Think about what "effect", means. It is not the proper term here.
If you are given sugar pills(placebo) and your heart rate actually goes down(effect)or your acne actually goes away(effect) that is the, Placebo Effect.
You heart rate could also go up(another effect) or the acne get worse(another effect) or a myriad of effects from the placebo to create the "placebo effect".
You are actually more or less referring to "confirmation bias". That is a perceived change based on expectations and may or may not be real, verfiable, correct or definitive.
It was $20k and you trust expensive things and you imagine that it all sounds better to validate your belief and your purchase.
There is also various types of "attribution error". Very commonly the music does sound better with the new cable so you "attribute", that to the cable rather what is more common in audio - simply paying more or different attention.
In any case the term Placebo Effect is being misused.
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"confirmation bias,
the tendency to process information by looking for, or interpreting, information that is consistent with one's existing beliefs. This biased approach to decision making is largely unintentional and often results in ignoring inconsistent information."
www.ftc.gov
