The country of Dantonia increased the size of its military force because its leaders inappropriately anticipated that their rival, the country of Ervintonia, would do the same. The Ervintonians subsequently felt it was necessary to respond to the Dantonian military buildup with a military expansion of their own. The Ervintonian response best illustrates the danger of:.

self fulfilling prophecies                          

Explanation:

In simple words, Self-fulfilling expectation relates to anyone "trying to predict" or anticipating something out of the social and economic-psychological phenomenon, so this "forecast" or assumption comes to fruition simply since one assumes it will, and their subsequent actions converge to satisfy certain beliefs.

This indicates that the values of the communities affect their behaviors.For instance anxiety is a self fulfilling prophecy as thinking that someone or something will cause you harm will eventually lead to mental stress and pressure.

answer; overt behavior;