Developed by developmental psychologist Mary Ainsworth, the secure base phenomenon describes how the primary caregiver (typically the mama) is attached to her baby or, in more technical terms, maternal-infant attachment patterns. Within this phenomenon, the primary caregiver, serves as a "secure base" for the baby's exploration of his physical environment. Ainsworth researched her secure base model in her experiment, the Strange Situation. Within the Strange Situation experiment, infants 12 months old are observed with their mothers in progressively more stressful situations. The infants and their mothers are placed in a room with toys for 21 minutes. During this time, a stranger comes into the room and begins to play with the child; the mother leaves the room and then returns on two occasions, and, lastly, the stranger leaves and again enters the room. Throughout the experiment, the infants’ behaviors of “proximity seeking, contact maintaining, avoidance [of interactions with the mother], and resistance [to any of the mother’s attempts at interaction]” (Huth-Bocks, Levendosky, Bogat, & von Eye, 2004, p.487) are observed. Based upon these observations, infants are classified as secure, insecure-avoidant, insecure-ambivalent, or disorganized-disoriented. The Strange Situation was combined with home observations to determine the mother's treatment of the infant during daily routines.
In the observations, securely attached babies typically only cried when they noticed their mothers were missing, whereas crying by insecurely attached infants was unpredictable and seemingly unrelated to the mother’s actions. So, securely attached babies look for and depend on their secure bases (mothers) for support in stressful situations, but babies that are not securely attached know that they cannot necessarily depend on their mothers.
Based upon these findings (which have been repeated by many researchers), we can conclude that responding to our babies needs is the most effective way to develop a secure attachment pattern with our babies. Popular "cry it out" methods certainly do not meet this criteria!
Ainsworth, M. & Marvin, R.S. (1995). On the shaping of attachment theory and research: An interview with Mary D. S.Ainsworth (Fall 1994). Monographs of the Society for Research in Child Development, 60(2/3), 2-21. Retrieved from http://www.jstor.org/stable/1166167
Allen, J.P., McElhaney, K.B., Land, D.J., Kuperminc, & Jodl, K.M. (2004). Stability and change in attachment security across adolescence. Child Development, 75(6), 1792-1805. Retrieved from http://www.jstor.org/stable/3696677
Huth-Bocks, A.C., Levendosky, A.A., Bogat, G.B., & von Eye, A. (2004). The impact of maternal characteristics and contextual variables on infant-mother attachment. Child Development, 75(2), 480-496. Retrieved from http://www.jstor.org/stable/3696653