Along the way, Spence has found that a strawberry-flavored mousse tastes ten per cent sweeter when served from a white container rather than a black one; that coffee tastes nearly twice as intense but only two-thirds as sweet when it is drunk from a white mug rather than a clear glass one; that adding two and a half ounces to the weight of a plastic yogurt container makes the yogurt seem about twenty-five per cent more filling, and that bittersweet toffee tastes ten per cent more bitter if it is eaten while you’re listening to low-pitched music. This year alone, Spence has submitted papers showing that a cookie seems harder and crunchier when served from a surface that has been sandpapered to a rough finish, and that Colombian and British shoppers are twice as willing to choose a juice whose label features a concave, smile-like line rather than a convex, frown-like one.