Medic. study—placebo tends to lack important effect—relevant to audio?
Reply #20 – 2013-06-10 16:19:38
it still remains the case that audio placebo effect disappears during a double-blind trial but the McGurk effect remains. That alone is sufficient for me to conclude that they're not necessarily connected, one might be true and the other false. The interaction known as the McGurk effect survives the double-blind trias, and this fact is verification that there is an interaction between our auditory and visual systems. If anything, this highlights the need for ABX testing of supposed audio differences. If our visual system can influence our auditory perception, this suggests that other brain functions may also influence our audio perception. What we expect to hear can influence how we hear, and what we hear. ABX tests provide a good tool for eliminating biases caused by placebo effects. Prior posts is this thread identified 3 possible placebo effects: 1) "A patient's faith or preconceptions produce a beneficial effect." Audio analogy: What we expect to hear has an influence on what we actually hear. For example; our expectations may cause us to focus on a particular sound, instrument, or band of frequencies, and we actually notice things that we had not heard before. 2) "Biased reporting" Audio analogy: We claim to hear a difference that we do not really hear (for a variety of reasons). 3) "The patient believes they experience something even though objective measurements don't support their belief." Audio analogy: A is identical to B, but listener becomes convinced that A sounds different than B. All three of the above placebo effects can be eliminated with a double-blind ABX test. Nevertheless, it should be noted that the ABX test is not perfect. Any ABX test will cause some disruption to the listening experience. It has been established that the McGurk effect can be diminished if the subject is engaged in tactile tasks while listening to the audio and viewing the video. The distraction caused by the tactile task seems to diminish the McGurk effect. Similarly, the tactile and visual tasks, and mental stress, associated with an ABX test may produce some minimal reduction in a subject's auditory acuity. The distractions caused by an ABX test may obscure some small audible differences, but the ABX test is very effective for eliminating placebo biases. ABX tests should be conducted in a way that minimizes the mental distractions caused by the test itself.