Monday, June 21, 2010

Bradshaw, Bears, Biases

Here's John Bradshaw, Emeritus Professor of Neuropsychology at Monash University, discussing perceptions and how easy they are to fool.

(M)y mother, in her final years living in the family home, regularly claimed that all the neighbours, and in fact everyone in the street, had left, either permanently or on vacation, and that she was some kind of survivor in an otherwise empty world. And indeed, that was probably how it was for her. When we showed her the neighbour on one side washing his car, and the one on the other side mowing the lawn, she would rationalise that they must have come back for a while, though in a few minutes she would again have forgotten that she'd seen them, and return to her solipsistic and lonely world. Thus confabulation involves the generation of 'fabricated' accounts of events or experiences, not necessarily deliberately, or with conscious intent, to compensate for and make sense of the paucity of retained information in memory. As a form of 'honest lying', it illustrates the constructive nature of autobiographical memory - something which, in this era of 'recovered memories' in the context of possible child abuse, we should always be aware of from a forensic viewpoint.

This, sadly, reminds EoR of all the anecdotal reports that homeopathy (and a plethora of other implausible therapies, such as reiki, faith healing, bowen etc etc) works because people claim to have "seen" an improvement. Professor Bradshaw also relates an interesting experiment where participants were told that the brightness of a background would change with a rising and falling tone (in fact, it didn't). Nonetheless, participants' pupils dilated as if it were.

Alternative practitioners (and their patients), because they want to believe, see what they expect. Even if you're ostensibly looking at it independently, aware of possible perceptual biases, Professor Bradshaw discusses some of the errors we are prone to. How much more so when we disregard those possibilities completely, in favour of a prejudicial outcome?

Professor Bradshaw also has some interesting remarks on the placebo and nocebo effects, and also mentions this famous advertisement:

Which rather begs the question, in a talk dedicated to the fallacies of perception and memory, why does Professor Bradshaw remember a gorilla instead of a bear?

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