Tuesday, December 07, 2010

The Truth Wears Off? Empirical Tests of Various Matters -- such as Eyewitness Identifications

Those of you who are interested in empirical studies of matters such as the accuracy of eyewitness identification really should read Jonah Lehrer, "The Truth Wears Off," The New Yorker 52 (December 13, 2010). [Yes, yes, I know: It's not December 13 yet. Complain to the New Yorker, please.]

A snippet:

Although verbal overshadowing remains a widely accepted theory [the theory that witnesses' verbal descriptions of events decrease the accuracy of the witnesses' identifications and descriptions] -- it's often invoked in the context of eyewitness testimony, for instance -- [Professor Jonathan] Schooler [of UCSB, a principal originator of the theory] is still a little peeved at the cosmos. "I know that I should move on already," he says. "I really should stop talking about this [that his repeated efforts to replicate earlier results of empirical tests show decreasing support for the hypothesis of verbal overshadowing]." That's because he is convinced that he has stumbled on a serious problem, one that afflicts many of the most exciting new ideas in psychology.
Following the report of this near-confession by Schooler, the article recounts the story of the Duke psychologist who in the 1930s conducted experiments that suggested that one of his human subjects [a student, Adam Linzmayer] had extra-sensory perception: The student seemed to have an uncanny ability to guess hidden cards in a special deck of cards: "[H]e averaged nearly 50% [accuracy in guessing cards correctly instead of the expected 20%], and pulled off several uncanny streaks, such as guessing nine cards in a row. The odds of this happening by chance are about one in two million. Linzmayer did it three times." However, the Duke psychologist, before publishing his experimental results, tested the student some more -- quite a bit more. What happened? After two years of additional experiments with the student and the deck of cards, this happened: "[T]he student lost his spooky talent." The Duke psychologist (Joseph Banks Rhine) was "forced to conclude that the student's 'extra-sensory perception ability has gone through a marked decline.'"


The dynamic evidence page

It's here: the law of evidence on Spindle Law. See also this post and this post.

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