I know this is still weak and there are a couple of unapologetic handwaving steps toward the end, but this was my thinking ...
Initially after birth, the mother is largely responsible for regulating the emotions of the infant through touch and feeding (Kopp, 1989). One of the first developmental tasks of the infant is to regain some of that control. But throughout the early months, crucial acts such as sucking, maternal contact, and hand-to-mouth movements can modulate negative emotional states. Infants are then exquisitely sensitive to affective communication from others, in a way that is contagious in both directions (Tomkins; Malatesta-Magai, 1991).
During active movement, the infant seeks out the mother during arousing events to help guide their own affective and behavioral response to the event. They thus not only seek out social information, but also use to to help self-regulate emotional states (Walden, 1991; Izard and Koback, 1991). Gradually, the child learns to perform the regulatory function themself to a greater degree, and eventually to use language for that purpose as well. Play becomes one of the most important developmental processes involved in coordinating the regulation of emotion.
The emotions that lead children to seek out their mother for emotional response information are probably rooted in attachment behavior. Children at play still continually reference their caretaker at moments of arousal. The frequency and intensity of this is temperamental, related especially to fearfulness and shyness (Izard and Koback, 1991).
Object relations theory, arising largely from Harry Stack Sullivan and Donald Winnicott, extends this notion to the internallization of the caretaker relationship, citing data that the mother is biologically synchronized with the child's needs. Bowlby (1969) contributed the idea that important internal models of self and others arise from early caretaker relating. Bowlby (1988) later emphasized that attachment behavior was analagous to physiological homeostasis, for regulating distance and accessibility. Sroufe and Waters (1977) indicated that attachment behavior revolved around an infant's sense of security in attachment behavior. Sroufe (1985) demonstrated that the stability of attachment cannot simply be attributed to temperament. Placid newborns become anxious and demanding if their mothers and rejecting and insensitive (Ainsworth, 1973). Thompson (1991) reviews the various assumptions about attachment behavior and its plasticity.
There is a tendency to impose earlier earlier attachment patterns onto current social interactions, a modified concept of "transference," which hypnotists often find accelerated or accentuated in their clients. In addition, in hypnosis, various observers have noted the presence of interaction synchrony. Interaction synchrony is a phenomenon observed in intimate communications in both humans and other animals where the posture, vocal qualities, movements, and other rhythmic behaviors of the participants subtly mirror each other in various ways, probably not coincidentally similarly to the way mother and baby reflect each other in subtle ways while they regulate each other's emotions from early after childbirth. (Reite; Banyai; Condon; Stern, Chapple).
My synthesis of this has been that early attachment behavior provides the biological template for playful synchronized interaction in hypnosis. This is only one dimension of hypnotic phenomena. Other demensions include (1) the cognitive mode associated with experiential mindset vs. observational mindset, (or inner focused exploration vs. exploring the environment); and (2) the use of language patterns to communicate expectations and help regulate emotional states.
References:
Kopp, C.B. (1989). "Regulation of distress and negative emotions: A developmental view." Developmental Psychology, 25:343-354.
Tomkins, SS. (1962, 1963, 1991, 1992). "Affect, imagery, and consciousness" Springer-Verlag.
Malatesta-Magai, C. (1991). "Development of emotional expression in infancy: General course and patterns of individual difference." in J. Garber and K.A. Dodge (eds). The development of emotion regulation and dysregulation, pp. 49-68. Cambridge University Press.
Walden, T.A. (1991). "Infant social referencing." in J. Garber and K.A. Dodge (eds). The development of emotion regulation and dysregulation, pp. 69-87. Cambridge University Press.
Izard, C.E. and Koback, R.R. (1991). "Emotions system functioning and emotion regulation." in J. Garber and K.A. Dodge (eds). The development of emotion regulation and dysregulation, pp. 303-321.. Cambridge University Press.
Bowlby, J. (1969). "Attachment and loss." Basic Books.
Bowlby, J. (1988). "Developmental psychiatry comes of age." American Journal of Psychiatry, 145: 1-10.
Sroufe, L.A. and Waters, E. (1977). "Attachment as an organizational construct." Child Development, 48:1184-1199.
Sroufe, L.A. (1985). "Attachment classification from the perspective of infant-caregiver relationships and infant temperament." Child Development, 56: 1-14.
Ainsworth, M.D. (1973). "The development of infant-mother attachment." In B.M. Caldwell and H.N. Riciutti (eds). Child development research, 1-95. Chicago University Press.
Thompson, R.A. (1991). "Construction and reconstruction of early attachments: Taking perspective on attachment theory and research." In D.P. Keating and H. Rosen (eds). Constructivist perspectives on developmental psychopathology and atypical development, pp. 41-67. Lawrence Erlbaum.
Reite, M. and Field, T. (eds.), (1985), Behavioral biology : The psychobiology of attachment and separation. Orlando: Academic Press. p. 415.
Banyai, E.I., (1985, August), On the interactional nature of hypnosis : A social psychophysiological approach. Paper presented at the 10th International Congress of Hypnosis and Psychosomatic Medicine, Toronto.
Banyai, E.I., Meszaros, I., Csokay, L. (1984, May), Further data on the psychophysiological factors of the interaction between hypnotist and subject. Paper presented at the 2nd European Congress of Hypnosis, Abano Terme-Padova, Italy.
Condon, W.S. and Ogston, W.D. (1967). A segmentation of behavior. Journal of Psychiatric Research, 5, 221-235.
Stern, D., (1982), Some interactive functions of rhythm changes between mother and infant. In M. Davis (Ed.), Interaction rhythms : Periodicity in communicative behavior, (pp. 101-117)New York : Human Sciences Press.
Chapple, E.D., (1982). Movement and sound : The musical language of body rhythms in interaction. In M. Davis (Ed.), Interaction rhythms : Periodicity in communicative behavior, (pp. 101-117)New York : Human Sciences Press.