The influence of pain extends everywhere through mental development, however. Its general effect is to dampen down or suppress the function which brings the pain; and in this its action is just the contrary to that of pleasure, which furthers the pleasurable function.
_Control Suggestion._--This covers all cases which show any kind of restraint set upon the movements of the body short of that which comes from voluntary intention. The infant brings the movements of his legs, arms, head, etc., gradually into some sort of order and system. It is accomplished by a system of organic checks and counter-checks, by which associations are formed between muscular sensations on the one hand and certain other sensations, as of sight, touch, hearing, etc., on the other hand. The latter serve as suggestions to the performance of these movements, and these alone. The infant learns to balance his head and trunk, to direct his hands, to grasp with thumb opposite the four fingers--all largely by such control suggestions, aided, of course, by his native reflexes.
_Contrary Suggestion._--By this is meant a tendency of a very striking kind observable in many children, no less than in many adults, to do the contrary when any course is suggested. The very word "contrary" is used in popular talk to describe an individual who shows this type of conduct. Such a child or man is rebellious whenever rebellion is possible; he seems to kick constitutionally against the pricks.
The fact of "contrariness" in older children--especially boys--is so familiar to all who have observed school children with any care that I need not cite further details. And men and women often become so enslaved to suggestions of the contrary that they seem only to wait for indications of the wishes of others in order to oppose and thwart them.
Contrary suggestions are to be explained as exaggerated instances of control. It is easy to see that the checks and counter-checks already spoken of as constituting the method of control of muscular movement may themselves become so habitual and intense as to dominate the reactions which they should only regulate. The associations between the muscular series and the visual series, let us say, which controls it, comes to work backward, so that the drift of the organic processes is toward certain contrary reverse movements.