Through learning, new bonds are formed.

Consequently a stimulus that originally caused crying may later cause us to get up, go to the bathroom, and put iodine on a scratched finger.

Or the olive, to which our original response was to spit it out of the mouth, is now eagerly sought for and eaten.

Or, the activity of shouting louder than the other boys and girls in order to get attention may in time be eliminated and in its place may develop a great interest in winning Phi Beta Kappa.

Relation of Formula to the Three Factors : Heredity, Environ- ment, and Training.