There is an earlier comment by Kaj Sotala, that I just read, that states, better and more succintly, what I was trying to say with 'our great brains have always been outside'. Let me quote

One central idea is that social communities are cognitive architectures the same way that individual minds are [4]. The argument is as follows. Cognitive processes involve trajectories of information (transmission and transformation), so the patterns of these information trajectories, if stable, reflect some underlying cognitive architecture. Since social organization - plus the structure added by the context of activity - largely determines the way information flows through a group, social organization may itself be viewed as a form of cognitive architecture.