Each month, Dr. Levy answers a common question he has received from professionals, caregivers and parents during three decades of pioneering work on attachment theory, treatment and training.

The human brain, especially the emotional limbic system, is an open-loop system because its growth and development are influenced by outside input.

This is in comparison to a “closed-loop” system like the circulatory system which regulates itself with no help from the outside world. The blood keeps flowing inside our body regardless of how others around us behave.

An old concept of the brain was that it also was a self-contained, hardwired machine that was unchangeable. We now know, when we look at the limbic system, that it relies on attuned and caring input from attachment figures for healthy growth and functioning.

A baby’s experiences with caregivers actually shape the way their brain forms and operates. Most affected are the parts of the brain that regulate self-control, the release of stress hormones and the way genes are expressed. Thus, it is common for children with histories of abuse, neglect and compromised attachment to have elevated stress hormone levels and problems with self-control.  They are often impulsive, inflexible and have temper tantrums. Inherited tendencies, such as mental illness, alcoholism and hyperactivity, are also more likely to emerge without the buffer of secure attachment.

A study with premature babies, by Ingersoll & Thomas, highlights the open-loop nature of an infant’s physiology. The researchers observed premature infants who slept with either a regular teddy bear or a “breathing bear” – a plush bear that inflates or deflates in sync with the breathing of the baby. They found that infants with breathing bears were able to sleep better and develop healthier respiration than those with static plush toys. (Of course, it would have been even better if they could have slept in their parent’s arms.)

Another example of the open-loop nature of the infant-mother connection is the hormone oxytocin. Oxytocin is a substance released during birth to induce contractions and during nursing to promote caregiving and attachments. As the newborn suckles the mother’s breast, more oxytocin is released in the mother’s body, which helps shrink the uterus, enhances the flow of milk and relaxes both mother and baby, affecting one another’s bodies, emotions and attachment.


Previous articles addressed questions about the Seven Functions of Secure Attachment, the Dependency Paradox, the importance of talking about trauma, the First Year Attachment Cycle, traits of successful and healthy adult relationshipsthe importance of hope as a part of treatment for traumathe core concepts of child development and parenting strategies for deescalating conflict.