From: Cathy Reason <Cathym.nul> Date: Wed, 25 Apr 2012 18:11:30 +0100 Archived: Fri, 27 Apr 2012 13:15:34 -0400 Subject: Bruner/Postman Experiment Unfortunately my ISP seems to have swallowed most of the mail yesterday; but I understand from the archives that Martin Shough has been asking about the Bruner/Postman 1949 experiment in recognizing anomalous playing cards, and its possible relevance to the perception and understanding of anomalies generally. Well first of all Martin, I'm afraid to report that I don't remember knowing anything about this experiment - or if I ever did, I've forgotten it. But I've just read through the paper and also watched the You-tube presentation of the experimental design, so here are my thoughts for what they're worth. Firstly I notice from the You-tube presentation that it's actually quite difficult to resolve the image in the time allowed, especially for the faster presentations. There also isn't time to scan the image and so only that part of the image close to the fixation point is properly resolved at all, the rest falling within peripheral vision. Secondly, there are potential confounding factors in the experiment which couldn't have been known about in 1949; for example, we now know that form and color are processed in separate visual pathways in the brain. So any experiment that relies, as this one does, on tinkering with the relationship between form and color is obviously on sticky ground at the outset. The paper seems to me to conform to the general pattern of papers in cognitive psychology - which is to say, it's about 5% actual evidence and about 95% interpretation. Regarded purely as psychophysical data, what is seems to tell us is that the more information you need to identify a target as distinctive, the longer it takes to process it, which is entirely consistent with the results from say, visual search experiments (although I should emphasize the Bruner/Postman paradigm is not a visual search experiment). As for the varous compromise and disruption effects, these seem to me most likely the result of interference between perception (which is highly time-constrained in this design) and associative memory. The sort of effect Kuhn is talking about seems to me to have a lot more to do with judgement and interpretation than it has to do with perception. And that is as they say, a whole other story. Cathy Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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