The Infant

At the origin, the boundary between persons does not give way. It has not yet been drawn.

What was observed

In the still-face procedure devised by Edward Tronick and colleagues (1978), a mother stops responding to her infant while continuing to look at it. Nothing is withdrawn but her live response. Within a minute or two the infant's attention, affect and posture begin to disorganize, and recovery on reunion is partial. Tronick's later work described ordinary interaction as mutual regulation: most of an infant's regulation of arousal is accomplished in the exchange, not in either partner. The still face removes one party from a process that requires two.

Daniel Stern described affect attunement: from about the ninth month, parents answer the dynamic shape of an infant's expression in another modality, many times an hour and largely without awareness. On his account, the sense of possessing a private interior is constructed in the second half of the first year, out of these matchings. The interior is built from the outside in.

The coordination is not confined to behaviour. Ruth Feldman and colleagues (2011) found that the heart rhythms of mothers and three-month-old infants coordinate during behavioural synchrony and lapse with it. Myron Hofer found, in infant rats separated from the mother, that each physiological system had been regulated by a different feature of her presence: his hidden regulators. Parts of the infant's physiology were, in a working sense, located in the mother.

States also appear in the infant that it never witnessed. Sara Waters, Tessa West and Wendy Berry Mendes (2014) stressed mothers out of their infants' sight; on reunion the infants showed heightened physiological stress of their own. Tiffany Field and colleagues (1988) found that infants of mothers with depressive symptoms carried the subdued style of that interaction into encounters with an unfamiliar adult.

What it shows

The received account holds that co-regulation yields to self-regulation, and the scaffold is removed once the self stands. James Coan (2006) placed married women under threat of mild shock: a stranger's hand reduced the neural response to threat, a husband's reduced it further, in proportion to the quality of the marriage. His social baseline theory proposes that the brain treats proximity to trusted others as its default. Adults are not released from regulation by others. It becomes invisible, and shows itself only when withdrawn.

The separate self was never the original condition. It is a construction, raised on a connection the construction does not abolish.