An intriguing new research effort suggests a child’s temperament is related to hormonal responses to stress.
In particular, temperamental patterns such as being cautious and submissive when confronting new environments, or bold and assertive in unfamiliar settings, are different responses that may help children navigate threatening environments.
The study is published online in the journal Development and Psychopathology.
“Divergent reactions — both behaviorally and chemically — may be an evolutionary response to stress,” said psychologist Dr. Patrick Davies, the lead author of the study.
“These biological reactions may have provided our human ancestors with adaptive survival advantages. For example, dovish compliance may work better under some challenging family conditions, while hawkish aggression could be an asset in others.”
This evolutionary perspective, said Davies, provides an important counterpoint to the prevailing idea in psychology that “there is one healthy way of being and that all behaviors are either adaptive or maladaptive.”
Coauthor Melissa Sturge-Apple, Ph.D., agreed: “When it comes to healthy psychological behavior, one size does not fit all.”
She added that the findings “give us insight into how basic behavioral patterns are also chemical patterns.”
In an attempt to understand the role of stress in children’s reactions, the researchers focused on parental conflict in young families.
“Research has shown that exposure to repeat aggression between parents is a significant stressor for children,” said Davies.
Two hundred and one two-year old toddlers, all from impoverished families with similar socioeconomic profiles, were studied. Based on interviews and questionnaires with the mothers, the authors assessed children’s exposure to levels of aggression between parents.
Investigators also documented the dove or hawk tendencies of the toddlers in a variety of unfamiliar situations. Children who showed dovish tendencies were vigilant and submissive in the face of novelty.
The toddlers clung to their mothers, cried, or froze when encountering new surroundings. Hawks used bold, aggressive, and dominating strategies for coping with challenge. They fearlessly explored unknown objects and new environments.
The next part of the study involved exposing the children to a mildly stressful simulated telephone argument between their parents — this caused distinct patterns of hormonal reactions to emerge among the 2-year olds.
Children exposed to high levels of interparental aggression at home showed different reactions to the telephone quarrel. Doves with parents who fought violently produced elevated levels of cortisol, a hormone that is thought to increase a person’s sensitivity to stress.
Hawks from such stressful home environments put the breaks on cortisol production, which is regarded as a marker for diminishing experiences of danger and alarm.
According to the authors, this high- and low-cortisol reactivity provides different developmental advantages and disadvantages. Heightened cortisol levels characteristic of the doves were related to lower attention problems but also put them at risk for developing anxiety and depression over time.
By contrast, the lower cortisol levels for hawks in aggressive families were associated with lower anxiety problems; however, at the same time, these children were more prone to risky behavior, including attention and hyperactivity problems.
Source: University of Rochester