Animals do, as a matter of fact, commonly repeat responses many times before changing them,[44] so that if only the law of exercise operated, learning would not be adaptive. It is the _effect_ of 2 that gives it the advantage over 1 and 3. Of two responses to the same annoying situation, one continuing and the other relieving it, an animal could never learn to adopt the latter as a result of the law of exercise alone, if the former was, originally, twice as likely to occur. 1 1 2 would occur as often as 2 and exercise would be equal for both. The convincing cases are, of course, those where learning equals the strengthening to supremacy of an originally very weak connection and the weakening of originally strong bonds. An animal’s original nature may lead it to behave as shown below:— 1 1 1 3 1 1 4 1 1 2 1 1 1 1 3 1 1 1 3 1 1 4 2 4 1 1 3 3 1 1 4 4 1 1 1 1 1 2, etc., and yet the animal’s eventual behavior may be to react to the situation always by 2. The law of effect is primary, irreducible to the law of exercise. THE EVOLUTION OF BEHAVIOR The acceptance of the laws of exercise and effect as adequate accounts of learning would make notable differences in the treatment of all problems that concern learning. I shall take, to illustrate this, the problem of the development of intellect and character in the animal series, the phylogenesis of intellectual and moral behavior. The difficulties in the way of understanding the evolution of intellectual and moral behavior have been that neither what had been evolved nor that from which it had been evolved was understood.