There’s a simple bias that seems to endure. Anyone may accidentally fall into its trap. Once they do, they make it impossible for others to avoid doing the same thing. It’s called the Survivorship Bias, and it can be used to convince people of nearly anything.
Let’s say that I walked up to you in the street and told you I was psychic and I could prove it. The more fleet-footed of you would manage to keep walking, but I think I’d back a few of you into a corner and make you watch my demonstration. It’s a video of me walking into a room with a group of witnesses. One of the witnesses – picked at random – flips a coin. After he flips, but before he shows the coin to anyone, I guess whether it’s heads or tails. He reveals it to the witnesses. I’m right. The demonstration goes on, and each time I’m right.
You’re naturally skeptical, so you start questioning the set-up. I have sworn statements from all the witnesses that they were all pulled off the street. I even have the video of the selection process. I have a video of what I did all that day, showing that I didn’t set up anything that might clue me in on the coin flip results. After a lot of investigating, you determine that there’s no trick. I’m just correctly guessing the coin each time. You’re right. There isn’t a trick.
There’s just hundreds days of set-up. On every one of those days, I have people go out and find witnesses, and people film me going about my business. On every one of those days, I walk into the room and start guessing. And on every one of those days, except for the day that I showed you, I guess wrong. I’ve showed you the one remarkable case, the one day that I guessed right.
To be fair, that’s more survivorship deception. But it does show how coincidence can, when taken out of context, look like something more. It’s been used by psychic researchers in the past. Test enough people and some of them will give answers that are coincidentally accurate. Then pretend that those people are psychics.
It’s also been used in economics. I had an economics teacher who joked that the best way to make millions as an investment adviser was to send out, to thousands of people, two variations of a letter. One would predict one trend in the stock market and the other would predict the opposite trend. Let the market takes its course. Strike the people that got the inaccurate letter from your mailing list. Then send out another set of letters. Repeat the pattern until you’ve got only a few clients, and each one of them is absolutely convinced that you’re infallible.
- The Survivorship Bias convinces people that psychics are real (io9.com)
- Psychic test cards were actually invented to make psychic tests easier (io9.com)
- The great psychic con (illuminutti.com)
- Secrets of the Psychics (illuminutti.com)
In which direction does this #train move? From which end of the tunnel is it arriving from? It might be both! Check if you can “see” a different direction each time you look at it? If you stare long enough, you might even make the train change its course. Today’s illusion works in the same manner, our famous Spinning Girl does. After all, there is no definitive answer, since the animation loops through just a few frames. On the other hand, if you recognise the station, you just might know the true answer after all 😉
- 10 Optical Illusions That Will Melt Your Mind (techeblog.com)
- Are These Circles Moving? 6 Places To Find Amazing Optical Illusions Online (makeuseof.com)
- Does The Optical Illusion Dress Really Work? (thefashionvisuals.wordpress.com)
- Optical illusions (gamesandotherstuff.wordpress.com)
- Optical Illusions (crazymadbaby.wordpress.com)
- Optical Illusions (theblondielocks.com)
- My Headache Is Gone. Solution To Tables Optical Illusion. (fellowshipofminds.wordpress.com)
- Which direction is the train moving? [Optical Illusion] (dottech.org)
Change blindness is the failure to detect non-trivial changes in the visual field. The failure to see things changing right before your eyes may seem like a design fault, but it is actually a sign of evolutionary efficiency.
The term ‘change blindness’ was introduced by Ronald Rensink in 1997, although research in this area had been going on for many years. Experiments have shown that dramatic changes in the visual field often go unnoticed whether they are brought in gradually, flickered in and out, or abruptly brought in and out at various time intervals. The implication seems to be that the brain requires few details for our visual representations; the brain doesn’t store dozens of details to which it can compare changes (Simons and Levin: 1998). The brain is not a video recorder and it is not constantly processing all the sense data available to it but is inattentive to much of that data, at least on a conscious level.
Change detection in films is notoriously poor when the change occurs during a cut or pan, as demonstrated by the color-changing card trick video and a number of other videos where a different actor appears after a cut, without the change being noticed by most viewers. Some experiments have shown that a person may be talking to someone (behind a counter, for example) who leaves (bends down behind the counter or exits the room) and is replaced by a different person, without the change being noticed.
Apparently, change blindness is due to the efficient nature of our evolved visual processing system, but it also opens the door to being deceived, much to the delight of magicians and sleight-of-hand con artists.
More examples of change blindness:
- Change Blindess (farisyakob.typepad.com)
- Did You Not Notice or Not Remember? (theness.com)
- Another Cool Change Blindness Video: The Color Changing Card Trick (capitalogix.typepad.com)