Generally , kids like sweet and salty and dislike sour and bitter. Do they generally like or dislike umami?
(yes, I know, only for certain values of “generally”, your kid may be different)
They love ketchup. Ketchup has a ton of umami.
And hot dogs. Those are nothing but umami, salt, and a bit of sweet.
As a kid, I loved meat.
and ketchup. Which is also umami, or so it seems.
Sweet signals energy. Salty signals, well, salt. Sour and bitter signal poison. Does umami signal anything?
(and pardon the gross oversimplification)
I think Kids are just like adults in their prevalent tastes. Some prefer sweets, some prefer savory, they just have more sensitive taste buds and prefer simpler flavours.
I always liked umami as long as I remember. Even as a toddler I loved soy sauce, pickles, sharp cheddar. Sure I liked ice cream but I would always choose cheese and crackers over cookies for a snack.
Unami is thought to indicate protein in food, glutamate is a salt of glutamic acid, a common amino acid in meats and cheese.
My kids dislike umami but they love mymami
Kids don’t hate sour - kids love sour when it’s with sweet, and often alone. Those insanely sour candies - I don’t think anybody BUT kids like them. And I know I wasn’t the only kid who ordered plates of lemons.
I used to drive my mom nuts because I would eat her bullion cubes. You can’t get much more umami than that.
I know there’s a lot of debate about why kids like the tastes they do, but I tend to think that the bitter/sour linkage to poison is a pretty weak argument. I think it has more to do with dietary requirements. Sweet, salt and umami all indicate necessary nutrients and are intrinsically linked to the presence of those things. Bitter and sour have no direct linkage with anything nutritive, and I think this simple absence of benefit is enough to explain taste preferences.
(That said, I think picky eaters have more to do with behavior issues than with taste issues. Get a kid hungry enough and they’ll eat anything. If they have a high calorie diet and have been snacking all day, they can afford to be picky and they can use it as a relatively harmless way to assert their independence.)
I never heard of “umami” until this thread. Are we in Japan now?
The Japanese have always believed there were five senses of taste. The one for protein was named umami. Apparently, it took the Western world centuries to figure out how our own tongues worked and we stole their word because “meatiness” just sounds stupid. 
Protein?
Is there any scientific evidence for this? I’m hoping to learn something today.
Kids seem to like strong, simple flavors, including sour, but I think they do dislike bitter. They also tend to dislike pungent and aromatic flavors (actually aromas, but often with a bitter flavor componant and/or distinctive mouth sensations like tingling, numbing, cooling, sinus-clearing, etc.) I loved at least some of those aromas/flavors as a kid, but I disliked others. I think that’s typical.
And if you want to taste pure umami, lick a bit of Accent (pure MSG). You’ll note the taste doesn’t correspond to any of the other four tastes. It’s sort of on the salty end of things, but it doesn’t really taste salty. It just tastes “full” and “mouth-watering” and savory.
I understand that some people report tasting it as sweet. Then again, taste is a subjective little thing to ask of random people.
In addition to information above, see Straight Dope Staff Report:
Besides sweet, sour, etc., is there a fifth taste sensation, “umami”? (December 31, 1999)
What is the chemical nature of bitterness, anyway? Sweet is sugar, salty is salt, sour is acid, umami is glutamate; what makes something bitter? Wikipedia mentions some bitter compounds but it doesn’t make it clear what the defining feature is.