The formation of such feelings of obligation and loyalty to any group with which one is identified is of the highest significance to good morale. It is the essence of the powerful patriotic feelings which are stimulated in times of war, but which have their origins in earliest childhood. …Not all Americans have been able to develop a range of identification large enough to include the nation and thus to develop strong feelings of loyalty and obligation. To some extent this ability seems to be a measure of social maturity.

p. 40 cited in: The Clare Spark Blog (2009) Strategic Regression in the greatest generation December 9, 2009 - Men Under Stress, 1945