The word invention is strange because most things are based on previous things, and thus I think it is important to mention human network formations.
Spatial and social orientation regarding the complex spread of the human population and how information was quickly spread from one set of groups to another. Hunter-gatherers used to know when potential problems were looming because, through complex networks, words traveled fast, which means the transition of culture and adaptation for specific things was possible on a higher and more efficient level in dynamic socio-interactive dimensions.
People seriously don't understand how crucial this was:
"Central-place foraging (CPF), where foragers return to a central location (or home), is a key feature of hunter–gatherer social organization. CPF could have significantly changed hunter–gatherers’ spatial use and mobility, altered social networks and increased opportunities for information-exchange. We evaluated whether CPF patterns facilitate information-transmission and considered the potential roles of environmental conditions, mobility strategies and population sizes. We built an agent-based model of CPF where agents moved according to a simple optimal foraging rule, and could encounter other agents as they moved across the environment. They either foraged close to their home within a given radius or moved the location of their home to new areas. We analysed the interaction networks arising under different conditions and found that, at intermediate levels of environmental heterogeneity and mobility, CPF increased global and local network efficiencies as well as the rate of contagion-based information-transmission. We also found that central-place mobility strategies can further improve information transmission in larger populations. Our findings suggest that the combination of foraging and movement strategies, as well as the environmental conditions that characterized early human societies, may have been a crucial precursor in our species’ unique capacity to innovate, accumulate and rely on complex culture."
You could forge relatively large extended mega populations: think of it as greater metro area of a city probably housing double the population of some urban cities with smaller sub-regions existing as an extension of that broad human complex. There is no doubt the foragers were not that extensive and that using sedentary analogy is not perfect but the population could widen by 10 times than what people thought if you factor in the networks on a regional scale:
That is an example of an emergent behavior among hunter-gatherer networks that, depending on environmental drivers and demographic settings, especially with types of subsistence and scales of collective lifeways, could construct everchanging synergistic motions of human macro interdependence that really can speculatively reach even beyond the complexity of sedentary citizen-states while being more eco-friendly, and adaptive.