The "flexion reflex" of the arm or leg, which pulls it away from a pinch, prick or burn, is the type of a host of defensive reactions--winking, scratching, rubbing the skin, coughing, sneezing, clearing the throat, wincing, limping, squirming, changing from an uncomfortable position--most or all of them instinctive reactions. With each goes some sort of irritating sensation, as pain, itching, tickling, discomfort; and a conscious impulse to get rid of the irritation is often present. When the simpler avoiding reactions do not remove the irritating stimulus, they are repeated more vigorously or give way to some bigger reaction tending towards the same result. The climax of the avoiding reactions is flight or running away. Akin to flight are cowering, shrinking, dodging or warding off a blow, huddling into the smallest possible space, getting under cover, clinging to another person; and most or all of these, too, are instinctive reactions. With flight and the other larger danger-avoiding reactions there is often present, along with the impulse to escape, the stirred up organic and conscious state of fear.
The stimuli that arouse movements of escape are of two sorts: those that directly cause some irritating sensation, and those that are simply signs of danger. The smaller avoiding reactions--flexion reflex, coughing, etc.--are [{143}] aroused by stimuli that are directly painful or irritating; whereas flight, cowering, etc., are mostly responses to mere signs of danger. A "sign of danger" is usually seen or heard at some distance, not felt directly on or in the body. Now, while avoiding reactions are attached by nature to the irritating stimuli, it is not at all clear whether escape movements are natively attached to any signs of danger, or, if they are, to what particular signs of danger they are attached. What visual or auditory stimuli, that are not directly irritating, will arouse escape movements in a young child? For the youngest children, no such stimuli have been found. You can easily get avoiding reactions from a little baby by producing pain or discomfort; you can get the clinging response by letting the child slip when he is being held in your arms; and you get crying and shrinking on application of a loud, grating noise, such a noise as is irritating in itself without regard to what it may signify. But you cannot get any shrinking from stimuli that are not directly irritating.
For example, you get no sign of fear from a little child on suddenly confronting him with a furry animal. With older children, you do get shrinking from animals, but it is impossible to be sure that the older child has not learned to be afraid of them. I have seen a child of two years simply laugh when a large, strange dog came bounding towards him in the park; but a year later he would shrink from a strange dog. Whence the change? There are two possibilities: either a native connection between this stimulus and the shrinking response only reached its maturity when the child was about three years old--and there is nothing improbable in this--or else the child, though actually never bitten by a dog, had been warned against dogs by his elders or had observed his elders shrinking from dogs. Children do pick up fears in this way; for example, children who are [{144}] naturally not the least bit afraid of thunder and lightning may acquire a fear of them from adults who show fear during a thunderstorm.
On the whole, the danger-avoiding reactions are probably not linked by nature to any special signs of danger. While the emotion of fear, the escape impulse, and many of the escape movements are native, the attachment of these responses to specific stimuli--aside from directly irritating stimuli--is acquired. Fear we do not learn, but we learn what to fear.
Crying.
We have the best of evidence that this is a native reaction, since the baby cries from birth on. He cries from hunger, from cold, from discomfort, from pain, and, perhaps most of all, as he gets a little older, from being thwarted in anything he has set out to do. This last stimulus gives the "cry of anger", which baby specialists tell us sounds differently from the cries of pain and of hunger. Still, there is so much in common to the different ways of crying that we may reasonably suppose there is some impulse, and perhaps some emotional state, common to all of them. The common emotion cannot be anger, or hunger, or discomfort or pain. To name it grief or sorrow would fit the crying of adults better than that of little children. The best guess is that the emotional state in crying is the feeling of helplessness. The cry of anger is the cry of helpless anger; anger that is not helpless expresses itself in some other way than crying; and the same is true of hunger, pain and discomfort. Crying is the reaction appropriate to a condition where the individual cannot help himself--where he wants something but is powerless to get it. The helpless baby sets up a wail that brings some one to his assistance; that is the utility of crying, though the baby, at first, does not have this result in view, but simply cries because he is hungry and helpless, uncomfortable and [{145}] helpless, thwarted and helpless. The child cries less as he grows older, because he learns more and more to help himself.
With the vocal element of crying goes movement of the arms and legs, which also has utility in attracting attention; but what may be the utility of shedding copious tears remains a mystery, in spite of several ingenious hypotheses that have been advanced to explain it.
Fatigue, rest and sleep.
That fatigue, primarily an organic state, gives rise to fatigue sensations and to a neural adjustment for rest--a disinclination to work any longer--and that drowsiness is a somewhat different organic state that gives an inclination to sleep--all this has been sufficiently set forth in earlier chapters. Going to sleep is a definite act, an instinctive response to the drowsy state. In the way of preparatory reactions, we find many interesting performances in birds and mammals, such as the curling up of the dog or cat to sleep, the roosting of hens, the standing on one leg of some birds; and we see characteristic positions adopted by human beings, but do not know how far these are instinctive and how far acquired. Closing the eyes is undoubtedly a native preparatory reaction for sleep.
Like the other responses to organic needs, rest and sleep figure pretty largely in the behavior of the adult, as in finding or providing a good place to sleep. Certainly if fatigue and sleep could be eliminated, as some over-enthusiastic workers have pretended to hope, life would be radically changed.