A series exploring over 50 core design concepts, from the 80/20 rule to storytelling, all based on Will Lidwell's landmark design books, Universal Principles of Design.
- Hi, I'm Jill Butler and this is Universal Principles of Design in this movie, Yellow Effects, or why there is nothing mellow about the color yellow. What's the best color to paint a firetruck? It turns out that the answer to this question is more complicated than you might think. There are two basic perspectives to consider when deciding the best color for anything. How we perceive color and how we think and feel about color.
The perception research tells us clearly that when it comes to seeing different colors the easiest color to see in all lighting conditions is greenish-yellow. For example, a study published in 1995 found that painting firetrucks greenish-yellow rather than red reduced the risk of visibility related accidents by three times. You heard that right, three times. So given this, it seems like a no brainer that firetrucks and other emergency vehicles should be painted greenish-yellow.
And in fact, that's what many fire departments did. In the 1970s, major cities, including Dallas, Cleveland, San Jose, Boston, and Jersey City followed the perception research and ordered yellow firetrucks. And how are those trucks doing today? All of these fire departments have switched back to red trucks. So what happened? In short, firefighters don't like yellow trucks. And why would this be, if yellow trucks are more easily detected and better at reducing accidents? This is where we get into how we think and feel about colors.
The color red is widely associated with courage, power, and dominance, characteristics commonly attributed to firefighters, about which they are rightfully proud. Take a big mighty truck, paint it red, give it a blaring siren and flashing lights, and it's the embodiment of everything firefighters stand for. Compare this to the color yellow. Have you ever heard the term yellow belly, or yellow streak? Yes, the color yellow is often associated with cowardice.
And the pukeish yellow green color of many of these firetrucks is also commonly associated with weakness and jaundice. So yellow is not just a symbol of cowardice, but of sickliness and weakness as well. Who wants to drive the big red firetruck in the parade? Everybody. Who wants to drive the big puke yellow firetruck in the parade? Nobody. And according to anecdotal reports, when cities started purchasing yellow firetrucks, firefighter morale plummeted, turnover increased, performance decreased.
And so after years of purchasing greenish-yellow firetrucks many cities switched back to red. Firefighter morale increased overnight, at least according to one Santa Monica Deputy Fire Chief who said, "They're real proud to have red again. "A lot of people will laugh at that, but... "I'm not making this up." The challenge of determining the one best color for firetrucks demonstrates the complexity of picking the one best color for anything. We interact with colors on many different levels at once.
Perceptual, cognitive, and emotional. And it's not always easy to net out all of the competing responses and predict the one overriding response. No color is more complex in this regard than the color yellow. Yellow effects are a set of cognitive and behavioral effects triggered by exposure to the color yellow. Let's look at a couple of context specific effects of yellow, and then briefly touch on some practical applications for designers.
First, the subtle effects of yellow on skin complexion and attractiveness. People who eat lots of ripe fruits and vegetables absorb yellow orange pigments called carotenoids, and these pigments give the skin a subtle yellow glow. Studies show that people with this yellow glow are rated more attractive than people without it. The thinking is that we've evolved to recognize this shade of yellow as a sign of good health and nutrition.
But, if the wrong shade of yellow is present, the kind of yellow caused by jaundice or liver disease, ratings of attractiveness plummet. And this association can generalize to related contexts as well. For example, yellow clothing generally decreases attractiveness in both males and females more than any other color, so beware the yellow wardrobe. Now, let's look at yellow in problem-solving contexts, where yellow increases attentional focus and perhaps even cognitive performance.
In a 10 year study carried out by five instructors evaluating the performance of accounting students on 4,000 tests, they found that students who took exams on yellow paper scored significantly higher than students who took the same exam on pastel green, pastel blue, or pastel pink paper. On a 100 point scale, the average score on yellow paper was almost a full 10 points higher than the average on pink paper. That's an increase of almost 10% based on just the color of the paper.
Nobody is sure why this happens, and more studies need to be done to replicate and figure it all out, but for now, it's a really significant result. So, what can designers do with yellow effects? Use yellow to grab attention. Yellow is the most visible color to the eye. This is likely the result of an evolved sensitivity for detecting ripe fruit. People are drawn to bright yellow warning signs, likely because their ancestors were drawn to bright yellow fruits like bananas.
Use bright yellow to signal energy and potency, and possibly to stimulate problem-solving. Yellow pills have stimulative effects, even when they're placebos, and yellow packaging makes products seem more energetic and effective than the same products in other colored packaging. Yellow legal pads and sticky notes may foster concentration and problem-solving. When attractiveness is key, skin tones with a subtle yellow glow can enhance attractiveness, but yellow apparel, especially on light-skinned people, should be avoided.
Yellow effects can be confusing because the color induces conflicting responses, like potency and weakness, or attractiveness and unattractiveness. Remember that the context as well as the specific shades and intensities of a color can make a big difference. Fluorescent yellow will create different reactions than light, pale yellow. The key is getting the right shade of yellow in the right context to achieve the desired result.
So whether you use yellow effects to attract and focus attention, to create a new line of cosmetics that gives people that healthy carotenoidal glow or to decrease traffic accidents and demoralize firefighters, remember, there is nothing mellow about the color yellow.
Skill Level Appropriate for all
Q: Why can't I earn a Certificate of Completion for this course?
A: We publish a new tutorial or tutorials for this course on a regular basis. We are unable to offer a Certificate of Completion because it is an ever-evolving course that is not designed to be completed. Check back often for new movies.