A fundamental question in the psychological sciences is the degree to which culture shapes core cognitive processes-perhaps none more foundational than how we perceive the world around us. A dramatic and oft-cited "case study" of culture's power in this regard is the Müller-Lyer illusion, which depicts two lines of equal length but with arrowheads pointing either inward or outward, creating the illusion that one line is longer than the other. According to a line of research stretching back over a century, depending on the society you were raised in (and how much carpentry you were exposed to), you may not see the illusion at all-an ambitious and influential research program motivating claims that seemingly basic aspects of visual processing may actually be "culturally evolved byproducts." This