By contrast technological change is very logical, as innovations provide greater efficiency and conveniences at lower costs. Our ancestors adopted the spinning wheel not as a “fad,” but because it shortened the time required to twist fibers into yarn. From this perspective cultural change appears bizarre. What were Stu and his imitators hoping to accomplish with a moptop? What changed their taste? Neither evolutionary biology nor economics can explain this behavior—the moptop has no intrinsic value over other styles, nor offers more tactile pleasure. Was the moptop a form of self-expression? If so, how did everyone know what feeling this particular haircut expressed? And why would everyone seek to express the same emotions through the same haircut at the same time?