Whether it's milk, carrots, or apple juice, kids ages 3-5 think food just tastes better when wrapped in the golden arches of McDonald's, a recent study finds. The study was aimed at low-income children enrolled in San Mateo, CA's "head start" programs, but the author of the study, Tom Robinson of Stanford University, believes the results would be similar for higher-income children. Quite simply, Robinson states, a child's sense of taste has been "physically altered by the branding."
While the extensive marketing of fast food products to young children has been decried by health advocates and in movies like Supersize Me, the fact that children prefer a branded food is probably heavily influenced by the larger advertising industry, not just McDonald's. I would guess that children prefer a branded grape juice to any generic grape juice, just as I'd guess that most people would give higher ratings to a Prada purse or Calvin Klein underwear than to their generic counterparts. Much of this can be explained by the connotations of happiness, wealth, and enjoyment that the ads convey.
On the other hand, some ads don't seem to convey much of anything, like this recent McDonald's commercial discussed by Slate.