Final answer:
The term referring to societies that developed without outside cultural influences is 'isolationism.' These societies have often maintained their cultural identity despite external pressures such as colonization, as seen in the forced assimilation in boarding schools in the 19th-century United States.
Step-by-step explanation:
The term for placing a group of people at a time when their culture had no outside influences is isolationism. This concept applies to societies that have developed their customs, traditions, and ways of life without the impact of external societies. These isolated communities are often referenced when discussing the effects of colonialism, imperialism, and globalization on indigenous cultures. Many groups have continuously existed dating back to periods before their lands were invaded or colonized, maintaining their unique cultural identity. Boarding schools' establishment in the late 19th century in the United States serves as a historical example of forced assimilation where native youth were stripped of their culture, tradition, and ways of worship to integrate them into the dominant society.