Spatial conditions have played an important rôle also in the development of societies. Through movements the individual or the group is able to pick and choose advantageous relations, and by changing its location adjust itself to changes in the food conditions. That the success of the group is definitely related to its motor capacity is revealed by the following law of population, worked out by statisticians for the three predominant races of modern Europe: In countries inhabited jointly by these three races, the race possessing the smallest portion of wealth and the smallest representation among the more influential and educated classes constitutes also the least migratory element of the population, and tends in the least degree to concentrate in the cities and the more fertile regions of the country; and in countries inhabited jointly by the three races, the race possessing the largest portion of wealth and the largest representation among the more influential and educated classes is also the most migratory element of the population, and tends in the greatest degree to concentrate in the cities and the more fertile portions of the country.[156] The primitive movements of population necessitated by climatic change, geological disturbances, the failure of water or exhaustion of the sources of food, were occasions for the expression of the superior motor disposition of the male and for the dislodgment of the female from her position of advantage. We know that the migrations of the natural races are necessary and frequent, and the movements of the culture races have been even more complex. The leadership of these mass-movements and spatial reaccommodations necessarily rests with the men, who, in their wanderings, have become acquainted with larger stretches of space; and whose specialty is motor co-ordination. The progressive races have managed the space problem best. At every favorable point they have pushed out their territorial boundaries or transferred their social activities to a region more favorable to their expansion. Under male leadership, in consequence, territory has always become the prize in every conflict of races; the modern state is based not on blood but on territory, and territory is at present the reigning political ideal. In the process of coming into control of a larger environment through the motor activities of the male, the group comes into collision with other groups within which the same movement is going on, and it then becomes a question which group can apply force more destructively and remove or bring under control this human portion of its environment. Military organization and battle afford the grand opportunity for the individual and mass expression of the superior force-capacity of the male. They also determine experimentally which groups and which individuals are superior in this respect, and despotism, caste, slavery, and the subjection of women are concrete expressions of the trial.