This is partially because children rank texture above taste. Sliminess, according to Pelchat, is a total turnoff (at least in our culture; it's all in what kids are used to). They also do not develop a taste for salt until they are about 5 months old, but from then on they like higher levels of salt than adults do.
Finally, consider what impact memory has on your food. People lose their sense of smell as they age, so our bodies compensate for that loss by allowing memory to help us know what we're eating. What's one thing 5-year-olds are lacking? Remembrances of madeleines past. Or even of cheeseburgers or tacos past.
I'm not saying children cannot be skewed by food snobs who hang out on Chowhound. Dr. Perri Klass, a professor of pediatrics and journalism at New York University, recalls the 4-year-old friend her daughter once brought home for a sleepover who rejected what she was serving for dinner and demanded noodles with pesto. Taken aback, Klass offered to run to the corner store, and the friend informed her contemptuously: "You don't buy pesto. You make pesto."
Even those of us who make pesto can't please children, though. I will never forget the first time I brought some carefully crafted tidbits involving goat cheese and roasted peppers to a party where a toddler was indulgently allowed to grab one with a grubby hand only to spit it out on the carpet.
But this is not just me yelling at kids to get off my lawn—I'm willing to set aside the annoying narcissism of parents who believe they have spawned a cross between Ferran Adria and Brillat-Savarin. On a larger scale, the trend emphasizes the worst of the food frenzy today: the celebration of celebrity and novelty over authenticity and seriousness. Julia Child was 50 years old before she flipped her first omelet on television. She got that gig only after studying at the Cordon Bleu and then devoting 10 years to perfecting Mastering the Art of French Cooking with two collaborators. Today chefs barely out of high school are competing on reality cooking shows, and the bar keeps being lowered, with Internet exposure for every little Thomas Keller. The movement devalues the very subject it pretends to celebrate. As Pelchat put it: "Kids would be excellent culinary guides. For food for other kids."