Our minds on media.

Musings on the effects of media on cognition.

Did The House Just Say “Get Out”?

This is a fantastic experiment that you can try on yourself, put on the web by Matt Davis of the The MRC Cognition and Brain Sciences Unit at Cambridge University. Essentially, when you first listen to the sound of a piece of speech that is artificially distorted, you won’t be able to make out much. Then, listen to the clear version of the speech and finally, listen to the distorted speech a second time. You’ll be surprised to discover just how much of it you can understand the second time. This effect results from your brain first attempting to make sense of stimulus for which it has no pattern to compare to. Once your brain is given a hint (through the clear speech sample) it can set up some expectations and decode the new stimulus utilizing those expectations.

This kind of experiment shows just how susceptible perception can be to top-down prediction in the brain and there are analogous effects on vision. I find that shows like Ghost Hunters and their audiences be getting fooled by just this kind of effect. Not to deny them their evidence—they have no doubt collected evidence—the question remains, how much can we trust ourselves to interpret the evidence perceptually? Objective measurement in these scenarios is crucial. The show isn’t called “Thermal Anomaly Hunters,” is it? So, I think its safe to say that the evidence is being examined with some bias. To the credit of the ghost hunters, I’ve never seen them state that they have caught a ghost or spirit on tape or with thermal imaging, only that they have observed something very strange, which is true. The question remains, what have they captured and how much of the picture are our own brains filling in for us?

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