Neurobiology, psychology, and social sciences study systems that are inherently complex and can't be broken down into simple parts without losing the systems' key properties. A new science, complexity theory, has revealed that the structure and behavior of such systems are often based on surprisingly simple rules. Interestingly, the brain has no intuition for this hidden simplicity. By combining basic theory and hands-on modeling in Mathematica, this course builds a deeper understanding for these systems. While no prior programming experience is required, students are expected to develop coding skills as part of the course.