the end a most surprising thing
may happen. The moral values may get reversed in the boy's mind. Bad may
come to represent the sum total of the satisfactory and desirable, while
good may represent the sum total of the unsatisfactory and the
undesirable. To the pained adult such a consequence is utterly
inexplicable, only because he fails to realize that all mental products
are developments. There is always a kind of reciprocity in emotional
transfer. The value of the modified factor recoils to the modifying
factor.

The whole mechanism of the transfer and of the recoil may best be
expressed in terms of the conditioned reflex of Pavlov. The flow of
saliva in a dog is a natural consequence to the sight and smell of food.
If concurrently with the smelling of food the dog is pinched, the pinch
ceases to be a matter for resentment. By a process of emotional
transfer, on being pinched the dog may show the lively delight that
belongs to the sight and smell of food. Even the salivary secretions may
be started by the transfigured pinch. It was the great operating
physiologist Sherrington who exclaimed after a visit to Pavlov that at
last he understood the psychology of the martyrs. But it is possible so
to load the smell of food with pain and damage that its positive value
breaks down. Eating-values may succumb to the pain values instead of the
pain to the eating-values. This is the prototype of the concept bad when
it gets overloaded with the emotional value of the intrinsically
desirable. The law of recoil seems to be a mental analogue of the
physical law that action and reaction are equal and in opposite
directions.

The second limitation to propaganda occurs when the reciprocal effects
of transfer exhaust the available motive forces of a mind. Propaganda
certainly weakens the forces that are appealed to too often. We are
living just now in a world of weakened appeals. Many of the great human
motives were exploited to the limit during the war. It is harder to
raise money now than it was, harder to find motives for giving that are
still effective. One of my former colleagues once surprised and shocked
me by replying to some perfectly good propaganda in which I tried to
tell him that certain action was in the line of duty, to the effect that
he was tired of being told that something was his duty, and that he was
resolved not to do another thing because it was his duty. There seems to
be evidence that in some quarters, at lea