For some time past it has been widely accepted that babies—and other creatures—learn to do things because certain acts lead to “rewards”, and there is no reason to doubt that this is true. But it used also to be widely believed that effective rewards, at least in the early stages, had to be directly related to such basic physiological “drives” as thirst or hunger. In other words, a baby would learn if he got food or drink or some sort of physical comfort, not otherwise. It is now clear that this is not so. Babies will learn to behave in ways that produce results in the world with no reward except the successful outcome.
Papousek began his studies by using milk in the normal way to “reward” the babies and so taught them to carry out some simple movements, such as turning the head to one side or the other. Then he noticed that a baby who had had enough to drink would refuse the milk but would still go on making the learned responses with clear signs of pleasure. So he began to study the children's responses in situations where no milk was provided. He quickly found that children as young as four months would learn to turn their heads to right or left if the movement “switched on” a display of lights—and indeed that they were capable of learning quite complex turns to bring about this result, for instance, two left or two right, or even to make as many as three turns to one side.
Papousek's light display was placed directly in front of the babies and he made the interesting observation that sometimes they would not turn back to watch the lights closely although they would “smile and bubble” when the display came on. Papousek concluded that it was not primarily the sight of the lights which pleased them, it was the success they were achieving in solving the problem, in mastering the skill, and that there exists a fundamental human urge to make sense of the world and bring it under intentional control.
According to the author, babies learn to do things which ________.
第一段最后部分提到“婴儿追求的是成功的结果”，文章最后一 段后半部分提到“it was the success they were achieving in solving the problem, in mastering the skill…”也印证了作者的观点，由此可知，是会给婴儿带来成功的感觉。故选C。
Papousek notice in his studies that a baby ________.
第二段提到“would refuse the milk but would still go on making the learned responses”，由此可知，即使不给婴儿牛奶，婴儿仍然会做简单的动作。故选C。
In Papousek's experiment babies make learned movements of the head in order to ________.
第二段中提到“if the movement “switched on” a display of lights, and indeed that they were capable of learning quite complex turns to bring about this result,”由此可知，婴儿学习扭头是为了“打开灯”。故选A。
The babies would “smile and bubble” at the lights because ________.
最后一段最后部分中提到“there seems a basic human desire to make sense of the world and bring it under intended control”可判断此项正确。故选D。
According to Papousek's experiment, the pleasure babies get in achieving something is a reflection of ________.
最后一段最后部分中提到，“a fundamental human urge to make sense of the world and bring it under intentional control”，由此可知孩子 成功的快乐是人类渴望认识世界，进而控制这个世界的反映。故选 A。