Judith Morgan, Ph.D.
University of Pittsburg
As my readers surely know, the nature-nurture debate in science
continues unabated. Especially in psychiatry. When it comes to certain
repetitive emotional reactions shown by a given individual, many in the field
prefer to believe that the individual was just born that way. The truth, as
described in Robert Sopolsky excellent book Behave,
is that we have hundreds or even
thousands of genes that make certain behaviors either a little more or a little
less likely. No complex human behavior is determined entirely by a gene or group
of genes. We are also strongly programmed to tend to react in certain ways to
the behavior of our kin group, although we can still make the difficult choice not
to once we reach a certain age.
There is without a doubt a strong genetic component to true
brain diseases like Major Depressive Disorder or schizophrenia, but the situation
for other emotional reaction patterns is that they, IMO, are far more affected
by the family environment than by any specific genes.
Some studies sure do point in this direction. For example, in a
recent study published in Biological Psychiatry: Cognitive Neuroscience
and Neuroimaging, Judith Morgan, Ph.D., recruited 49 children aged six to
eight without a history of psychiatric
illness. Half the kids' mothers had a history of clinical depression, and half had no
psychiatric history. To measure reward-related brain activity, children played
a video game in which they
guessed which of two doors contained a hidden token while they underwent
functional magnetic resonance imaging (fMRI).
Depression may disrupt parents' capacity for emotional
socialization, a process by which kids learn from their parents' reactions to
their emotional
responses. Positive socialization responses include
acknowledgment, imitation, and elaboration, whereas negative or emotionally
dampening parental responses may be dismissive, invalidating, or punitive.
Mothers participating in the study completed an extensive
questionnaire designed to measure parental emotional socialization by
presenting a dozen situational vignettes of children's displays of positive
emotions and collecting parents' reactions to them. Children with a maternal
history of depression were more likely to have reduced reward-related activity
in a part of their brains that handles this, but only if their mothers reported
less enthusiastic and more dampening responses to their children's positive
emotions, the researchers found.
"In our study, mothers' own history of depression by itself
was not related to altered brain responses to reward in early school-age
children," said Dr. Morgan. "Instead, this history had an influence
on children's brain responses only in combination with mothers' parenting
behavior, such as the ability to acknowledge, imitate, or elaborate on their
child's positive emotions."
