The restriction of studies of human intellect and character to studies of conscious states was not without influence on a scientific studies of animal psychology.

Human beings are accustomed to think of intellect as the power of having and controlling ideas and of ability to learn as synonymous with ability to have ideas. But learning by having ideas is really one of the rare and isolated events in nature.

On the whole, the psychological work of the last quarter of the nineteenth century emphasized the study of consciousness to the neglect of the total life of intellect and character.

To the intelligent man with an interest in human nature it must often appear strange that so much of the energy of the scientific world has been spent on the study of the body and so little on the study of the mind.

Psychology helps to measure the probability that an aim is attainable.

So the animal finally performs in that situation only the fitting act.