As the writer of a blog on design and joy, a lot of what I think about on a daily basis has to do with things that delight us in spite of their apparent non-utility. In addition to rainbows, I write about things like kaleidoscopes and swimming pools, confetti and hot air balloons, bioluminescence and optical illusions. By understanding the aesthetic essence of these simple pleasures—color, light, growth, abundance, magic—my goal is to look for more ways to design delight into our world.

It's not lost on me that this can seem like a frivolous endeavor and from time to time I've been asked to answer for the energy I devote to pleasure and whimsy. While I'm waxing prosaic on treehouses or designing "joyful" service gestures, other designers are engaged in tackling weighty issues of clear importance to humankind. Providing sanitation in the developing world, developing systems for healthy eating, creating sanitary products for women in Africa: these "design for the other 90%" projects make a measurable improvement in the quality of millions of people's lives. Through design, they reduce the spread of disease, enable social change and create thriving new economies that raise entire communities above the poverty line. Their projects highlight the unique contribution of designers and design methods to solving real, thorny systems challenges. By contrast, delight seems like a first-world design problem: something you do only after you have ample food, clean water, safe shelter, clothing, education, healthcare and all the other basics, covered.

But as a design principle, delight is deceptively light. Over the past few years, research has been accumulating to show that positive emotion offers real benefits in terms of physical well-being, social interaction, and professional performance. Through neuroscience, we're learning that pleasure taps into primal pathways in the brain that were formed to help us grow, develop and prosper. And through psychological studies of people and relationships, we're discovering that joy inspires attitudes and behaviors that lead to greater health and success. So when I think about delight in the context of design, it's not just about delight as an end (however appealing that may be), but about delight as a conduit to bigger goals and to better lives.

What follows are four examples of the tangible benefits of designing with joy in mind, a sort of case "in defense" of delight that serves as both support for efforts to integrate positive emotion into design, as well as a design challenge for those inspired to try. Delight facilitates creativity, learning, and innovation.

Contrary to the stereotype of the depressed artistic genius, it's happier people who tend to be more creative. In a much-cited study, subjects who were primed to be in a good mood out-performed subjects with neutral or negative priming on a set of creativity tasks. For example, positively primed subjects came up with more ideas on an ideation task than those who were neutral or negatively primed. Researchers believe this is because positive emotions like delight have a broadening effect on our mind and our senses. While negative emotions make us close down and focus on the things immediately in front of us, positive emotions encourage open-mindedness and exploration. The experience of delight tells the brain it is safe from urgent threats and can afford to daydream, look around and contemplate the new and unusual. Support for this theory that positive emotion widens our perspective comes in the form of studies showing that people in good moods take in more visual information than those in bad moods. In a positive mood, we literally see more out of our peripheral vision which leads us to form more accurate mental maps of the world.

Publicolor, a non-profit organization that uses color to brighten the walls of inner city schools, is an initiative that uses this principle to stimulate positivity in a context of learning and creativity. Through the design of environments that stimulate more positive emotion, they create a setting that primes kids to be open and curious, ready to learn. In contrast, think about the dull grey walls of the typical office cubicle. If we know there's a link between creativity and positivity, how would we redesign these spaces to put our workers in a better frame of mind to generate innovative ideas?

Delight inspires behavioral change.

You've probably already seen one or more videos from The Fun Theory, an initiative from Volkswagen that explores the role of delight in changing behavior. Done as a series of experiments, with data to reinforce the benefits, Fun Theory projects demonstrate the value of positive emotion in motivating personal and social change. In one of the first projects, designers turned a staircase into a giant working piano, and then measured the number of people who took the stairs vs. the escalator. With the piano in place, the stairs saw a 66% increase in usage. In another recent experiment, a speed camera was rigged to offer a random reward to drivers who slowed down below the speed limit (distributing the proceeds from the fines collected by drivers who were over the limit). The lottery offer resulted in a remarkable 22% decrease in average speed on the roadway. In countless other contexts, delight is being used as way to inspire behavioral change, from grassroots to more macro levels. In initiatives like Park Day, movements like guerilla gardening, yarnbombing or favela painting, and efforts like those of Design 99 in Detroit and the street artist, Rainbow Warrior, in Albuquerque, we can see a rising current of "joyful activism" that uses pleasurable aesthetics to make people reconsider their actions and inspire change.

In their book Switch: How to Change When Change is Hard, Chip and Dan Heath note that while most people think a negative state would motivate change (through punishment or fear), it's actually positive emotion that makes people most receptive to change. This may be because enjoyment stimulates dopamine, a neurotransmitter related to pleasure, and the body's natural opioids, painkilling chemicals. Together, these chemicals function as a natural reward system that incentivizes good behavior and may help dull the pain of change.

Though the value of a polka dotted walkway might not be obvious, the emotion it evokes may have real benefits.

Delight increases cooperation and collaboration.

It may sound obvious that delight has strong positive effects when it comes to social interaction, but the results are powerful when it comes to building lasting relationships and achieving goals that require the coordination of many people's efforts. Positive emotions increase hormones that relate to bonding, so stimulating delight through a shared positive experience can cement a group and lead to better outcomes. Psychologists have observed that positive priming increases group identity and desire to collaborate; positive emotions can even increase likelihood to help a stranger. This fits with the finding that positive emotions broaden our view. While sadness, annoyance and frustration make us close in and focus on our own perspective, positive emotions open our minds to engaging with others and considering alternative points of view. Many workshop planners know this intuitively, designing a fun warm-up or outing into the beginning of a day of intense collaboration to make the group feel more unified before rolling up sleeves to dig into the hard stuff. Especially when dealing with strong differences, priming a group with a sense of delight can ease tensions and make overcoming silos easier.

Designers use delight in clever ways to facilitate collaboration. One of my favorite examples is PlayPumps, an economical water pumping system that uses the power of children playing on a merry-go-round to bring clean water up from underground for use. Another example is Contrail, a "bicycle advocacy tool" (recently funded on Kickstarter) that lays a thin line of colored chalk in the path of a rider. As riders continue to cover the same ground, a trail of brightly colored lines emerges, alerting cars to make room for cyclists. Through the design of delight, Contrail turns cyclists into advocates for each other, and makes others aware of the need for safe behavior in a positive way.

Delight contributes to long-term health and well-being.

Though we typically think about delight in the context of emotional well-being, it's becoming an accepted fact that positive emotion has clear benefits in terms of health and longevity. Some of the benefits of joy that studies have demonstrated include increased cell growth rates, lowered heart rates, reduced blood pressure and stress hormones. Scientists suggest positivity can decrease inflammatory responses while strengthening the immune system. Studies have even shown a correlation between positive emotion and a longer life.

This may be the most immediate and relevant of the effects of delight as a design principle. With all the debate around reducing healthcare costs and increasing standards of care, could designing delight be part of a regimen of preventative healthcare? Could there be value in decisions as simple as a fresh coat of paint or some more natural light? In fact, it has been shown that natural light speeds healing and can even reduce the need for pain medication among patients in hospitals. (This makes sense: If positive emotion stimulates our natural opioids, then it would be plausible that it could reduce pain.) A recent New York Times article described the effects of positivity in healthcare in a novel approach to caring for Alzheimer's patients offered at a care center called Beatitudes. There, caregivers have seen dramatic results by using art, music and foods such as chocolate instead of medication to generate positive emotions and calm patients. Even small-scale efforts to design for delight may have positive effects on our health. These canes by Allan Zadeh and Rie Nørregaard, for example, may trigger a small moment of joy that runs counter to the pain of an injured leg.

For an increasing number of people I talk to, delight needs no defending. As the evidence mounts that joy isn't just good for our souls, but also our bodies, businesses and communities, we're starting to take designing for delight seriously. And I think the serious benefits will continue to manifest themselves: whether in more innovative businesses, activist movements that gain greater traction, health initiatives that subtly improve well-being or schools that produce more engaged, prepared students, we'll start to see more measurable evidence that delight can be a powerful tool in shaping a better world.