The idea of some kind of social being forming when we gather for a joint purpose has been around for a while. This quote is from 1924. It was published by sociologists Park and Burgess in the Introduction to the Science of Sociology.
Whoever be the individuals that compose it, however like or unlike be their mode of life, their occupations, their character, or their intelligence, the fact that they hare been trans- formed into a crowd puts them in possession of a sort of collective mind which makes them feel, think, and act in a manner quite different from that in which each individual of them would feel, think, and act, were he in a state of isolation. There are certain ideas and feelings which do not come into being or do not transform themselves into acts except in the case of individuals forming a crowd. The psychological crowd is a provisional being formed of heterogeneous elements, which for a moment are combined, exactly as the cells which constitute a living body form by their reunion a new being which displays characteristics very different from those possessed by each of the cells singly.