"Attention!" shouts the officer as a preliminary to some more specific command, and the athletic starter calls out "Ready!" for the same purpose. Both commands are designed to put the hearer in an attitude of readiness for what is coming next. They put a stop to miscellaneous doings and clear the way for the specific reaction that is next to be called for. They nullify the effect of miscellaneous stimuli that are always competing for the hearer's attention, and make him responsive only to stimuli coming from the officer. They make the hearer clearly conscious of the officer. They arouse in the hearer a condition of keen alertness that cannot be maintained for more than a few seconds unless some further command comes from the officer. In all these ways "attention" in the military sense, or "readiness" in the athletic sense, affords a good picture of the psychology of attention. Attention is preparatory, selective, mobile, highly conscious. To attend to a thing is to be keenly conscious of that thing, it is to respond to that thing and disregard other things, and it is to expect something more from that thing. Attention is, in a word, exploratory. To attend is to explore, or to start to explore. Primitive attention amounts to the same as the instinct of exploration. Its natural stimulus is anything novel or sudden, its "emotional state" is curiosity or expectancy, and its instinctive reaction consists {245} of exploratory movements. Its inherent impulse is to explore, examine, or await. Attention belongs fundamentally among the native forms of behavior. The child does not have to learn to attend, though he must learn to attend to many things that do not naturally get his attention. Some stimuli naturally attract attention, and others attract attention only because of previous experience and training. In considering the whole subject of attention, then, we shall in part be dealing with native responses, and in part with responses that are acquired. But the great laws of attention, which will come to light in the course of the chapter, are at the same time general laws of reaction, and belong under the head of native characteristics. The Stimulus, or What Attracts Attention We can attend to anything whatever, but are more likely to attend to some things than to others. As stimuli for attention, some objects are much more effective than others, and the question is, in what way one object has the advantage over another. There are several ways, several "factors of advantage", we may call them.