Just as the touch and pain nerves enmesh closely our body, warning us against hurtful stimulations, so we may say that fear, through our distant receptors of sight, hearing and smell, surrounds us, warning us against enemies, or inimical, suspicious objects, and forces. Were it not for the fear instinct, directly awakened, the animal threatened with danger would not have the time and the strong impulse to get ready for defense or for escape, by running or by hiding.

The fear instinct is of the utmost importance in animal life. Looked at from this standpoint the fear instinct is as important in animal economy as the skin which covers our body, which, by pain and hurts, warns of external injurious objects, and has an important function of warding off incessant invasion of disease-bearing organisms. In nervous ills we find the same fundamental factors:—self-preservation and the fear instinct.

[CHAPTER II]
STAGES OF FEAR

The fear instinct in its course of development passes through three stages:

I.The Stimulating Stage
II.The Arrestive, or Inhibitory Stage
III.The Paralyzing Stage.

In its milder forms when the fear instinct is but nascent, it serves as a sort of trigger to the activities of the organism. The animal may for a moment stop whatever activities and pursuits in which it happens to be engaged, and have its interest turn in the direction of the particular new stimulus, whether it be of an auditory, visual, or olfactory character. The fear instinct is just strong enough to suspend present interests, and direct its activities to the new source of the unknown stimulus.

When the source is unfamiliar, the animal becomes prepared for action. The energies are aroused for attack, or for hiding, freezing, or running, according to the mode of defense to which the animal has been adapted in its adjustments to the stimulations of its environment. The lion, the tiger, the skunk, the snake, the bird, the rabbit, the squirrel will act differently, according to their natural disposition in response to external objects and stimuli.

While the motor system may react differently in various animals, the fear instinct is alike in all of them. This stage of the fear instinct should be regarded as the healthy physiological reaction to strange and new stimuli, and is essentially protective, inasmuch as it serves for the arousal of energy and proper reactions of self-defense, characteristic of the particular individual.