You report that Adam Alter and Daniel Oppenheimer from Princeton University have shown that the value of a coin or banknote depends on its familiarity (“Look and Feel,” April 5, 2008). Their research relied on thirty-seven randomly-selected volunteers from the university’s canteen. Wow! I am sure that many of your readers will be just as impressed as I am. Anyone who has ever exchanged money on the street in a struggling economy anywhere around the world will tell you the same. In some parts of the world, the dollar rules, while the euro or the pound rule in others. In addition, experienced travelers can tell you exactly how much you can get in local currency for a range of foreign ones, regardless of their relative values in New York, London, or Tokyo. All this is so very familiar that I wonder about the Princeton researchers: do they ever travel abroad?