The Origin and Nature of Emotions(9)

The type of adequate stimuli of the solesof the feet, the distribution of the ticklish points upon them,and the associated response, leave no doubt that these ticklish pointswere long ago established as a means of protection from injury.Under present conditions they are of little value to man.The adequate stimulus for the ticklish points of the ribs,the loins, the abdomen, and the neck is deep isolated pressure,probably the most adequate being pressure by a tooth-shaped body.The response to tickling in these regions is actively and obviouslyself-defensive. The horse discharges energy in the form of a kick;the dog wriggles and makes a counter-bite; the man makes effortsat defense and escape.There is strong evidence that the deep ticklish points of the bodywere developed through vast periods of fighting with teeth and claws(Fig. 9). Even puppies at play bite each other in their ticklishpoints and thus give a recapitulation of their ancestral battlesand of the real battles to come (Fig. 10). The mere fact that animalsfight effectively in the dark and always according to the habitof their species supports the belief that the fighting of animalsis not an intellectual but a reflex process. 

There are no ruleswhich govern the conduct of a fight between animals. The eventsfollow each other with such kaleidoscopic rapidity that the processis but a series of automatic stimulations and physiologic reactions.Whatever their significance, therefore, it is certain that man didnot come either accidentally or without purpose into possessionof the deep ticklish regions of his chest and abdomen.Should any one doubt the vast power that adequate stimulationof these regions possesses in causing the discharge of energy,let him be bound hand and foot and vigorously tickled for an hour.What would happen? He would be as completely exhausted as though he hadexperienced a major surgical operation or had run a Marathon race.A close analogy to the reflex process in the fighting of animalsis shown in the role played by the sexual receptors in conjugation.Adequate stimulation of either of these two distinct groupsof receptors, the sexual and the noci, causes specific behavior--the one toward embrace, the other toward repulsion.

 Again, one ofthe most peremptory causes of the discharge of energy is that dueto an attempt to obstruct forcibly the mouth and the nose so thatasphyxia is threatened. Under such conditions neither friendnor foe is trusted, and a desperate struggle for air ensues.It will be readily granted that the reactions to prevent suffocationwere established for the purpose of self-preservation, but the dischargeof nerve-muscular energy to this particular end is no more specificand no more shows adaptive qualities than do the preceding examples.Even the proposal to bind one down hand and foot excites resentment,a feeling originally suggested by the need for self-preservation.No patient views with equanimity the application of shacklesas a preparation for anesthesia.We have now considered some of the causes of those discharges of nervousenergy which result from various types of harmful physical contact,and have referred to the analogous, though antithetical,response to the stimulation of the sexual receptors.The response to the adequate stimuli of each of the several receptorsis a discharge of nerve-muscular energy of a specific type; that is,there is one type of response for the ear, one for the larynx,one for the pharynx, another for the nose, another for the eye,another for the deep ticklish points of the chest and the abdomen,quite another for the delicate tickling of the skin, and stillanother type of response to sexual stimuli.According to Sherrington, a given receptor has a low thresholdfor only one, its own specific stimulus, and a high thresholdfor all others; that is, the doors that guard the nerve-pathsto the brain are opened only when the proper password is received.