THere, little girl. Have a nice, cool glass of apple juice with a dead grasshopper in it.

What's wrong? Not to your liking? A little repulsive, is it?

Excellent.

And so goes another day of research in the lab of psychologist Paul Rozin at the University of Pennsylvania, where 3- to 12-year-olds were offered various foods to figure out at what age children grasp the concept "gross."

In addition to juice containing a dead, sterilized grasshoper, the 65 children were offered juice stirred with a new comb; juice stirred with a comb taken from a purse (to make it look used); a cookie covered with "grasshopper powder" (actually green flour and sugar); and a plain, dead grasshopper.

No child, not even the 3-year-olds, would eat the grasshoppers. Rozin and his colleagues found a gradual increase, starting at about age 6, in the number of other foods rejected, they reported in the journal Developmental Psychology.

Between age 3 and age 6, about 75 percent of the children would drink juice stirred with the "dirty" comb. Between ages 9 and 12, only 9 percent would drink the same juice, according to a synopsis of the study in Science News.

The researchers have not yet figured out why younsters are more willing than adults to consume these foods.

The study was a follow-up of earlier work, in which children were told stories about dog feces in glasses of milk and asked whether they would want to drink the milk. Most rejected it by age 7.