How to See Color and Paint It is about a practical situation where you really would rather not be subject to color illusions.
It starts out with an illusion like the one in this article-- the author takes his art students to the shore of a bay at dusk and asks them the color of the brick buildings across the water. The students say "red", and then he has them look at the buildings through holes in 3" x 5" cards--- the buildings are blue!
Not only are colors as perceived strongly influenced by expectation and surrounding colors, a lot about them operates below conscious perception. It's claimed that white is actually a hue which is too light to be easily identified, black a hue which is too dark, and gray and brown are respectively cool and warm hues which are too muted to be easily identified.
The book teaches artists to look at color patches on objects individually, and mix paint separately for each patch rather than mixing what seems to be the major color of an object, and then modifying it for highlights and shadows.
I haven't worked with paints following the book, but just reading it produces a short-lived altered state of consciousness for me. It's amazing to realize that a t-shirt when being worn in ordinary light shows only very small areas of the color I think it is-- most of it is either much lighter or darker.
Now I'm wondering if having read that book a few times is part of why clumsy photoshopping drives me up the wall. The way the light and shadows don't hang together is completely obvious to me, and it must not show up for most people.
Crashing Through, a book about a man who recovered his sight late in life and had to work very hard to make any sense of it, mentions that if you can't see optical illusions (these were perspective-based, not color-based), you can't see.
Any theories about why people like optical illusions?
Sorry no cite, but I've read about a study which found that women in bars tend to prefer the dominant man in a group. This led me to deduce two possibilities: a group of men which trade off dominance on different nights (this would take a lot of trust, I think), or more likely, men who keep going to bars with the same dominant friends, hoping that the magic will rub off on them, and not realizing that their own subordination is the magic.
This led me to deduce two possibilities: a group of men which trade off dominance on different nights (this would take a lot of trust, I think)
This is pretty much a standard part of being a 'wingman' in PUA.
-- traditional Jewish joke
Related to: Anchoring and Adjustment
Biases are “cognitive illusions” that work on the same principle as optical illusions, and a knowledge of the latter can be profitably applied to the former. Take, for example, these two cubes (source: Lotto Lab, via Boing Boing):
The “blue” tiles on the top face of the left cube are the same color as the “yellow” tiles on the top face of the right cube; if you're skeptical you can prove it with the eyedropper tool in Photoshop (in which both shades come out a rather ugly gray).
The illusion works because visual perception is relative. Outdoor light on a sunny day can be ten thousand times greater than a fluorescently lit indoor room. As one psychology book put it: for a student reading this book outside, the black print will be objectively lighter than the white space will be for a student reading the book inside. Nevertheless, both students will perceive the white space as subjectively white and the black space as subjectively black, because the visual system returns to consciousness information about relative rather than absolute lightness. In the two cubes, the visual system takes the yellow or blue tint as a given and outputs to consciousness the colors of each pixel compared to that background.
So this optical illusion occurs when the brain judges quantities relative to their surroundings rather than based on some objective standard. What's the corresponding cognitive illusion?
In Predictably Irrational (relatively recommended, even though the latter chapters sort of fail to live up to the ones mentioned here) Dan Ariely asks his students to evaluate (appropriately) three subscription plans to the Economist:
Ariely asked his subjects which plan they'd buy if they needed an Economist subscription. 84% wanted the combo plan, 16% wanted the web only plan, and no one wanted the print only plan. After all, the print plan cost exactly the same as the print + web plan, but the print + web plan was obviously better. Which raises the question: why even include a print-only plan? Isn't it something of a waste of space?
Actually, including the print-only plan turns out to be a very good business move for the Economist. Ariely removed the print-only plan from the choices. Now the options looked like this.
There shouldn't be any difference. After all, he'd only removed the plan no one chose, the plan no sane person would choose.
This time, 68% of students chose the web only plan and 32% the combo plan. That's a 52% shift in preferences between the exact same options.
The rational way to make the decision is to compare the value of a print subscription to the Economist (as measured by the opportunity cost of that money) to the difference in cost between the web and combo subscriptions. But this would return the same answer in both of the above cases, so the students weren't doing it that way.
What it looks like the students were doing was perceiving relative value in the same way the eye perceives relative color. The ugly gray of the cube appeared blue when it was next to something yellow, and yellow when it was next to something blue. In the same way, the $125 cost of the combo subscription looks like good value next to a worse deal, and bad value next to a better deal.
When the $125 combo subscription was placed next to a $125 plan with fewer features (print only instead of print plus web) it looked like a very good deal – the equivalent of placing an ugly gray square next to something yellow to make it look blue. Take away the yellow, or the artificially bad deal, and it doesn't look nearly as attractive.
This is getting deep into Dark Arts territory, and according to Predictably Irrational, the opportunity to use these powers for evil has not gone unexploited. Retailers will deliberately include in their selection a super deluxe luxury model much fancier and more expensive than they expect anyone to ever want. The theory is that consumers are balancing a natural hedonism that tells them to get the best model possible against a commitment to financial prudence. So most consumers, however much they like television, will have enough good sense to avoid buying a $2000 TV. But if the retailer carries a $4000 super-TV, the $2000 TV suddenly doesn't look quite so bad.
The obvious next question is “How do I use this knowledge to trick hot girls or guys into going out with me?” Dan Ariely decided to run some experiments on his undergraduate class. He took photographs of sixty students, then asked other students to rate their attractiveness. Next, he grouped the photos into pairs of equally attractive students. And next, he went to Photoshop and made a slightly less attractive version of each student: a blemish here, an asymmetry there.
Finally, he went around campus, finding students and showing them three photographs and asking which person the student would like to go on a date with. Two of the photographs were from one pair of photos ranked equally attractive. The third was a version of one of the two, altered to make it less attractive. So, for example, he might have two people, Alice and Brenda, who had been ranked equally attractive, plus a Photoshopped ugly version of Brenda.
The students overwhelmingly (75%) chose the person with the ugly double (Brenda in the example above), even though the two non-Photoshopped faces were equally attractive. Ariely then went so far as to recommend in his book that for best effect, you should go to bars and clubs with a wingman who is similar to you but less attractive. Going with a random ugly person would accomplish nothing, but going with someone similar to but less attractive than you would put you into a reference class and then bump you up to the top of the reference class, just like in the previous face experiment.
Ariely puts these studies in a separate chapter from his studies on anchoring and adjustment (which are also very good) but it all seems like the same process to me: being more interested in the difference between two values than in the absolute magnitude of them. All that makes anchoring and adjustment so interesting is that the two values have nothing in common with one another.
This process also has applications to happiness set points, status seeking, morality, dieting, larger-scale purchasing behavior, and akrasia which deserve a separate post