Inspired by the teachings of Smohalla, Chief Joseph of the Nez Percé in Idaho rebelled in 1877. Before he was trapped only thirty miles short of refu… - Peter Farb

The Hopewell fused elements of the Adena, the Archaic, and other Woodland patterns of life. Thus, it cannot technically be identified as a culture. ...Rather, the Hopewell people were an amalgam of many societies whose customs varied greatly, but who were bound together by... a cult of the dead and a trade bond... a network of trade linked widely separated areas of the continent.

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...

To say that the invention "was in the air" or "the times were ripe for it" are just other ways of stating that the inventors did not do the inventing, but that the cultures did.