A researcher shows a five-year-old child a nine-inch bowl containing popcorn and an empty six-inch bowl. After watching the researcher pour the popcorn out of the nine-inch bowl and into the six-inch bowl, the child tells the researcher that she is certain the smaller bowl has more popcorn than the larger bowl had in it. The researcher then says, "Okay, let's see what happens when we put the popcorn back into the big bowl." As the child watches, he returns the popcorn to the nine-inch bowl. The child then says that there is now less popcorn in the larger bowl then there was in the smaller bowl. This child has yet to acquire what Jean Piaget called