...they were set off on a thousand mile march—called to this day "the trail of tears" by the Cherokee—that was one of the notable death marches in hi… - Peter Farb

As this cultural inadequacy becomes apparent even to the most conservative of its members, the culture may deteriorate to such an extent that it literally dies.

The seventeenth-century Iroquois... practiced a dream psychotherapy that was remarkably similar to Freud's discoveries two hundred years later. The Iroquois recognized the existence of an unconscious, the force of unconscious desires, the way in which the conscious mind attempts to repress unpleasant thoughts, the emergence of unpleasant thoughts in dreams, and the mental and physical (psychosomatic) illnesses that may be caused by the frustration of unconscious desires. The Iroquois knew that their dreams did not deal in facts but rather in symbols. ...And one of the techniques employed by the Iroquois seers to uncover the latent meanings behind a dream was free association...

After the Spaniards settled the Southwest, the Navajo began another burst of cultural borrowing—or, more actually, stealing. Spanish ranches and villages were so depleted of horses—not to mention sheep—that by 1775 the Spaniards had to send to Europe for 1,500 additional horses. After the Pueblo Rebellion against the Spaniards was put down in 1692, many Pueblo took refuge with their Navajo neighbors—and taught them how to weave blankets, a skill for which the Navajo are still noted, and to make pottery. During this time the Navajo probably absorbed many Pueblo religious and social ideas and customs as well, such as ceremonial paraphernalia and possibly the Pueblo class system.