Confirmation bias

A colleague of mine sent me an amusing powerpoint file in which it looks like the slideshow can guess your decision. You should look at it if you can understand French. (spoiler below) (serious comment further below)

Your are shown a series of playing cards, asked to mentally select one (say outloud which one it is) and then, incredibly, the next slide shows which card you have selected.

The trick rests upon the so-called "confirmation bias". See below the first series of playing cards.

And now the second series.

Notice that none of the cards in the first series appears in the second series. But because the pattern is similar in both series, and because you focused solely on the one card that mattered to you, you may experience a strange feeling of ESP.

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I am not sure if my colleague was serious when he asked me what was the trick. Maybe he was pulling my leg, or maybe it was a challenge.

But the really very serious comment I want to make is that our profession (academic research) is littered with such (tragic) examples. There are very high profile examples of factoids (a missing card) brandished as evidence while the context is completely ignored.

If the prevalence of the confirmation bias doesn't bother you, go back to the beginning of this post, download  the powerpoint slide show and experience it for yourself. Very powerful indeed.