Design affects the brain. The design of our spaces can heal us, hurt us, and alter the way we think. Scientists and designers are starting to understand how and why. And as they learn more, they’re fueling the development of new design tools and approaches that are rapidly changing the built world around us. More and more, design can be used to achieve specific outcomes or to create certain effects. Scientists know enough to change our lighting or acoustics to do no harm and to enhance mental and physiological and health outcomes and to design cities that curb violence. This is a long and interesting essay.