Mead never used the term "symbolic interactionism" and published no systematic statement of the theory in his lifetime; Mind, Self, and Society (1934) was assembled by his students from lecture notes after his death, and Blumer built and named the formal theory decades later, working from that posthumously edited material rather than a text Mead himself finalized, leaving open how much of "Meadian" theory is Mead's own view versus his editors' and Blumer's synthesis.
What would resolve this A comparison of surviving primary lecture transcripts and Mead's own published journal articles against Blumer's later three-premise formulation, checking which elements can be traced directly to Mead's own words versus editorial or Blumer's interpretive additions.
OpenHistory of sociological theoryWikipedia: Symbolic Interactionism