Lasting emotional tie between people such that the individual strives to maintain closeness to the object of attachment and acts to ensure the relationship continues
Securely attached infants are more sociable with peers, better problem solvers, more persistent and enthusiastic, more socially competent, fewer behavioural problems, and more likely to remember positive emotional events
Rutter found 2,000 boys aged 9-12 were four times more likely to become delinquent if separation related to family discord rather than through illness or death of their mother
Gross early privation (psychological rather than nutritional) resulted in cognitive deficits at age 4 if it went on longer than the first 6 months of the child's life