Humans are, in essence, evolved great apes, sharing a very high percentage of their genes with the three great apes: chimpanzees, gorillas, and orangutans. The neurology of all great apes allows them to communicate in episodes of interaction; and indeed, the genetic wiring for language comprehension exists among all great apes. The interpersonal capacities of great apes are outlined with an eye to understanding the neurological basis of human social interaction. Interaction among humans is very much the same as that among great apes but, at the same time, is very unique because of a much larger brain, both sub-cortically where emotions are generated, and neo-cortically where cognitions are formed and stored. Moreover, while great apes can understand human languages, they cannot speak because they lack the requisite vocal tract and key neurological structures, such as Broca’s area, but they can communicate via sign languages and computers using pictograms that can be arrayed to produce sentences carrying common meanings. By comparing great ape and human brains, it is possible to understand not just speech and symbolic culture that differentiates humans from great apes, but also the elaboration of the dimensions along which human interaction occurs. These dimensions make human interaction more complex than among great apes, but the neurology involved is not all that unique, except for a few key structures and, more importantly, the size and connectivity within and among sub-cortical and neo-cortical areas of the human brain. An effort is made to conceptualize these interpersonal dynamics in an expanded view of the approach employed by George Herbert Mead but with an emphasis on the neurological basis of human interaction.