Bowlby's monotropic theory- social releasers and the critical period
Babies born with social releasers- set of innate 'cute' behaviours (smiling, cooing and gripping) that encourage attention from adults by activating their attachment system (i.e. love the baby). Attachment is a reciprocal process- both mother and baby have an innate predisposition to become attached.
Interplay between infant and adult attachment system builds relationship. Critical (sensitive) period = 2 years. No attachment= difficult later on