He thus tends, as psychologists say, to "generalize," that is, to take up certain general attitudes which will answer for a great many details of experience.

On the side of the reception of his items of knowledge this was called Assimilation, as will be remembered.

This saves him enormous trouble and risk; for as soon as an object or situation presents itself before him with certain general aspects, he can at once take up the attitude appropriate to these general aspects without waiting to learn the particular features of the new.

The ability to do this shows itself in two rather different ways which seem respectively to characterize man on the one hand and the lower animals on the other.
With the animals this tendency to generalize, to treat objects in classes rather than as individuals, takes the form of a sort of composition or direct union of brain pathways.

Different experiences are had, and then because they are alike they tend to issue in the same channels of action.