Well, we know that kids are hard-wired to prefer sweet and salty tastes and umami, which is more of a savory taste. It's thought that these tastes are predispositions that have evolved to help children to be oriented toward foods that contain energy. And at birth, infants tend to reject sour and bitter tastes – the thinking being that these tastes may be signals to avoid certain toxins. While some taste predispositions do vary from child to child, the preferences for those basic tastes are hard-wired