All babies are born with some natural smarts, but youngsters learn more about the worldwhen this innate intelligence is__(15)__ cognitive psychologists Aimee E. Stahl and LisaFcigenson discovered in a study published recently in the journal Science.The researchers took babies who could not yet talk through four experiments to provetheir theory.        They presented the babies with situations they could predict, as well as some thatwere unexpected, and__(16)__ their reactions.        Early childhood is an important developmental period in a person's life because infantbrains quickly absorb and process reams of information. A small child will pick up a foreignlanguage easier and faster than a teenager or an adult will. What is so exciting about thisrescarch is that how much, at such a young age, children are processing, and problem-solvingand figuring out.
       What the Hopkins psychologists discovered about the babies is no different from thelearning process of adults. Scientists, for instance, who think more intently, run moreexperiments and try to develop new theories when they run across an unusual or unexpectedfinding.
       One way researchers studied the children was by using a ball and a wall. They rolled theball down a ramp and toward the wall. In one trial, the ball hit the wall as a baby wouldnaturally expect.__(17)__ the ball passed through a hidden door in the wall, sparking thebabies' inquisitiveness.
        The response by the infants was not _(18)_ or automatic, Stahl said, but acontemplative attempt to figure out what happened.
        The findings show that when confronted with __(19)__ babies learn about the objectbetter, explore the object more and come up with their own hypothesis for why the objectbehaved in a certain way.
【題組】15.( )
(A) boosted with nutrients
(B) confronted with challenge
(C) infused with insecurity
(D) stimulated by leverage