ScepticaTV
3 HN recommenders · recommended in 6 months, 2013–2017
47:03 · 408K views · Feb 12, 2011
Derren Brown's TV special in which he convinces a person he has a system for predicting horse race winners, demonstrating how survivorship bias and selective outcomes can fake predictive powers.
HN cites it as the classic demonstration of survivorship and confirmation bias in betting, trading and prediction claims.
6 comments from Hacker News
This reminds me of Derren Brown's awesome "The System" special: this video More info for anyone who hasn't had the pleasure of knowing who Derren Brown is: [LINK] Derren Brown is a British illusionist, mentalist, trickster, hypnotist, painter, writer, and sceptic. He is known for his appearances in television specials, stage productions, and British television series such as Trick of the Mind and Trick or Treat. Since the first broadcast of his show Derren Brown: Mind Control in 2000, Brown has become increasingly well known for his mind-reading act. He has written books for magicians as well as the general public. Though his performances of mind-reading and other feats of mentalism may appear to be the result of psychic or paranormal practices, he claims no such abilities and frequently denounces those who do. Brown states at the beginning of his Trick of the Mind programmes that he achieves his results using a combination of "magic, suggestion, psychology, misdirection and showmanship".
I don't know if your assessment of the study is valid (it seems a little simplistic to think that they wouldn't account for this to be honest), but what you describe is classic Survivorship Bias. Here's an entertaining video from Derren Brown that shows how to use this technique to convince people you have psychic powers: this video Edit: also see the comment about the Miracle Man scam in this thread.
For a good example of confirmation bias watch Derren Brown's "The System" [1] where he makes a woman believe an unknown benefactor has a foolproof system for betting on horses. "Mail Order Prophet" [2] by Alfred Hitchock has a similar idea. [1] this video ] [2] [LINK]
On the other hand objective randomness is a black box. You can describe how it behaves at the surface level (so functionally it is usable), but by definition you can't have a finite model of it, so what is inside? No answer by definition - something infinite. So why X happens instead of Y? 1. Let's propose an unexplainable, unmodellable infinite entropy source under everything vs. 2. X happens and so do Y, and one is observed at a certain probability due to anthropic principle - like this: this video The first is somehow psychologically less satisfying answer for me, although - of course - I accept that calculation works either way. The second at least not an unimaginable infinite, and in the end leaves me with less "why?".
Derren Brown used this approach to convince people he had a system for predicting the winners of horse races: this video