Great description of engaging the brain in design from frogdesign's Innovation Starts with Empathy:
"The reptilian brain is dedicated solely to survival, whereas the outer neocortex hosts reason and higher intelligence. In between these two, however, lies the sweetest part of the apple: the limbic system. It’s a collection of processors and hormone controllers that govern memory and emotions. The limbic system also enables us to interpret the emotions of others. It is the part of our brain that allows us to care."