https://en.wikipedia.org/wiki/Colwyn_Trevarthen
https://www.ncbi.nlm.nih.gov/pubmed/11205623
https://ddpnetwork.org/blog/parent-child-relationships/colwyn-trevarthens-chapter-infant-intersubjectivity/
http://www.psychology.emory.edu/cognition/rochat/lab/Three%20Levels%20of%20Intersubjectivity%20in%20Early%20Development.pdf
Trevarthen (Bråten & Trevarthen, 2007; Trevarthen, 1974) described what he called stages of primary and secondary intersubjectivity as appearing in the first year (tertiary intersubjectivity appears in ages 3–6). “Primary Intersubjective Dialogues [involve] protoconversations and reciprocal sympathetic imitation … [leading] to more lively jokes and games rich in emotions of ‘other awareness’” (Bråten & Trevarthen, 2007, p. 22). Secondary intersubjective attunement involves subject-subject-object interactions in which infant and mother jointly inspect objects, emotionally referenced in a process laden with trust.
Leffert, Mark. Psychoanalysis and the Birth of the Self (p. 99). Taylor and Francis. 2018, Kindle edition.
