Societies that formerly relied solely on flint and stone as their main materials for making tools and weapons now began to use copper and bronze as well. Society itself seems to change in this period with a shift away from a focus on the group to that of the individual, hinted at by a move from communal burial to single burials or cremations. This may indicate the development of hierarchies in society and the migration of people or new ideas from the continent. There is also evidence of greater competition for the control of land leading to the beginnings of tribal life and warfare.