Along with manipulation goes the examination of objects by the hand, the mouth, the eyes and ears, and all the senses. Listening to a sudden noise is one of the first exploratory reactions. Following a moving light with the eyes, fixing the eyes upon a {155} bright object, and exploring an object visually by looking successively at different parts of it, appear in the first few months of the baby's life. Exploration by the hands and by the mouth appear early. Sniffing an odor is a similar exploratory response. When the child is able to walk, his walking is dominated largely by the exploring tendency; he approaches what arouses his curiosity, and embarks on little expeditions of exploration. Similar behavior is seen in animals and is without doubt instinctive. With the acquisition of language, the child's exploration largely takes the form of asking questions. The stimulus that arouses this sort of behavior is something new and unfamiliar, or at least relatively so. When an object has been thoroughly examined, it is dropped for something else. It is when the cat has just been brought into a strange house that she rummages all over it from garret to cellar. A familiar object is "taken for granted", and arouses little exploratory response. Quite a group of conscious impulses and emotions goes with exploratory behavior. The feeling or impulse of curiosity is something that everybody knows; like other impulses, it is most strongly felt when the end in view cannot be immediately reached. When you are prevented by considerations of propriety or politeness from satisfying your curiosity, then it is that curiosity is most "gnawing". A very definite emotion that occurs on encountering something extremely novel and strange is what we know as "surprise", and somewhat akin to this is "wonder". Exploration, though fundamentally a form of playful activity, has great practical value in making the child acquainted with the world. It contains the germ of seeking for knowledge. We shall have to recur to this instinct more than once, under the head of "attention" and again under "reasoning". {156} Manipulation and exploration go hand in hand and might be considered as one tendency rather than two. The child wishes to get hold of an object, that arouses his curiosity, and he examines it while handling it. You cannot properly get acquainted with an object by simply looking at it, you need to manipulate it and make it perform; and you get little satisfaction from manipulating an object unless you can watch how it behaves. Tendencies running counter to exploration and manipulation. Just as playful activity in general is limited by the counter tendencies of fatigue and inertia, so the tendency to explore and handle the unfamiliar is held in check by counter tendencies which we may call "caution" and "contentment".