Traits that were suited to the earlier habits of life then became relatively useless in the individual struggle for existence.
And those elements of the population, or those ethnic groups, which were by temperament less fitted to the predatory life were repressed and pushed into the background.

On the transition to the predatory culture the character of the struggle for existence changed in some degree from a struggle of the group against a non-human environment to a struggle against a human environment.

This change was accompanied by an increasing antagonism and consciousness of antagonism between the individual members of the group.

The conditions of success within the group, as well as the conditions of the survival of the group, changed in some measure; and the dominant spiritual attitude for the group gradually changed, and brought a different range of aptitudes and propensities into the position of legitimate dominance in the accepted scheme of life.

Among these archaic traits that are to be regarded as survivals from the peaceable cultural phase, are that instinct of race solidarity which we call conscience, including the sense of truthfulness and equity, and the instinct of workmanship, in its naive, non-invidious expression.
Under the guidance of the later biological and psychological science, human nature will have to be restated in terms of habit; and in the restatement, this, in outline, appears to be the only assignable place and ground of these traits.