UCLA researchers examine impact on amygdala.
Children who experience profound neglect have been found to be more prone to a behavior known as “indiscriminate friendliness,” characterized by an inappropriate willingness to approach adults, including strangers.
UCLA researchers are now reporting some of the first evidence from human studies suggesting that this behavior is rooted in brain adaptations associated with early-life experiences. The findings appear in the Dec. 1 issue of the peer-reviewed journal Biological Psychiatry.
The UCLA group used functional magnetic resonance imaging (fMRI) to demonstrate that youths who experienced early maternal deprivation — specifically, time in an institution such as an orphanage prior to being adopted — show similar responses to their adoptive mother and to strangers in a brain structure called the amygdala; for children never raised in an institutional setting, the amygdala is far more active in response to the adoptive mother.
This reduced amygdala discrimination in the brain correlated with parental reports of indiscriminate friendliness. The longer the child spent in an institution before being adopted, the greater the effects.
“The early relationship between children and their parents or primary caregivers has implications for their social interaction later in life, and we believe the amygdala is involved in this process,” said Aviva Olsavsky, a resident physician in psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA and the study’s first author. “Our findings suggest that even for children who have formed attachments to their adoptive parents, this early period of deprivation has led to changes in the brain that were likely adaptations and that may persist over time.”
Indiscriminate friendliness is in some sense a misnomer. The behavior is not characterized by a deep friendliness but simply by a lack of reticence that most young children show toward strangers.
“This can be a very frightening behavior for parents,” said Nim Tottenham, an associate professor of psychology at UCLA and the study’s senior author. “The stranger anxiety or wariness that young children typically show is a sign that they understand their parents are very special people who are their source of security. That early emotional attachment serves as a bedrock for many of the developmental processes that follow.”