The McGurk Effect – Do you always hear what you think you hear?
I saw this clip for the first time yesterday during a training session about unconscious bias. The context then was a discussion of how we make quick decisions about things (and people) relying on contextual associations of which we are often entirely unaware. The clip illustrates how difficult it is to overrule some things your brain does automatically even when you know they are wrong.
Related to this is something I’ve noticed in a slightly different setting. Not having a TV set I do sometimes watch DVDs on my laptop, but the screen is quite small and, for a person of my advanced years, rather difficult to view comfortably for a long period. A while ago I started plugging my laptop into a monitor instead. When I do that I usually put the laptop well out of the way, which means moving the relatively small loudspeaker out of the line of sight between myself and the screen. It is however immediately noticeable that the sound immediately seems to be coming from the screen rather than the speaker. I guess this is yet another example of the visual overruling the auditory which it does in the McGurk effect.
Oh, and I just remembered this, which I heard a while ago at a public talk given by Simon Singh. I guess many of you will have come across it before, but there’s no harm in repeating it. I don’t know why it popped into my head at this particular moment, but perhaps it’s because I’ve been reading some stuff about how my colleagues in gravitational wave research use templates to try to detect specific patterns in noisy data. The method involves cross-correlating a simulated signal against the data until a match is obtained; the problem is often how to assess the probability of a “chance” coincidence correctly and thus avoid spurious detections. The following might perhaps be a useful warning that unless you do this carefully, you only get out what you put in!
This is an excerpt from the classic track Stairway to Heaven, by the popular beat combo Led Zeppelin, played backwards. I suggest that you listen to it once without looking at the words on the video, and then again with the words in front of you. If you haven’t heard/seen it before, I think you’ll find it surprising…
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In the Dark 
May 19, 2016 at 2:30 pm
This reminds me of another remarkable example which reveals the workings of the brain with regards to weighing the information from several senses:
Brain studies reveal that when we see someone get hurt, for example in the arm, the same areas light up in the brain as when we are experiencing real pain in the arm-empathetic response. In practice we might feel uncomfortable when watching others in pain, however we don’t feel the pain it self. However, patients with amputated arms/legs report feeling real pain if they watch someone being hurt in an area of the body they no longer have.
It has been suggested that in non amputated individuals, the message the brain gets from the skin, overrules the empathetic response.
May 19, 2016 at 4:17 pm
What I’d be interested to see is multiple alternative and equally compelling words fitted to Stairway backwards, and similar retrofits for other tracks.
May 20, 2016 at 1:01 am
There is a wholly explicit link between satanism and some rock music (which is why I choose my rock music carefully), and obviously the most insidious stuff in any field of human endeavour is implicit rather than explicit; but, as there is zero evidence that the brain can hear something and then decode it backwards, I am a lot more interested in what you hear when music is played forward.
May 20, 2016 at 9:23 am
Don’t worry, nor did Plant.