Overprotective parents inhibit more than their kids’ freedom:
they may also slow brain growth in an area linked to mental illness. Children
whose parents are overprotective or neglectful are believed to be more
susceptible to psychiatric disorders—which in turn are associated with defects
in part of the prefrontal cortex. To investigate the link,
Kosuke Narita of Gunma University, Japan, scanned the brains of 50 people in
their 20s and asked them to fill out a survey about their relationship with
their parents during their first 16 years. The researchers used a survey called
the Parental Bonding Instrument, an internationally recognized way of measuring
children’s relationships with their parents. It asks participants to rate their
parents on statements like "Did not want me to grow up", "tried to control
everything I did" and "tried to make me feel dependent on her/him". Narita’s
team found that those with overprotective parents had less grey matter in a
particular area of the prefrontal cortex than those who had had healthy
relationships. Neglect from fathers, though not mothers, also correlated with
less grey matter. This part of the prefrontal cortex develops during childhood,
and abnormalities there are common in people with schizophrenia and other mental
illnesses. Narita and his team propose that the excessive release of the stress
hormone cortisol (皮质醇)—due either to neglect, or to too much attention and
reduced production of dopamine as a result of poor parenting leads to stunted
grey matter growth. Anthony Harris, director of the Clinical
Disorders Unit at Westmead Hospital in Sydney, Australia, says the study is
important for highlighting to the wider community that parenting styles can have
long-term effects on children. But he adds that such brain differences are not
always permanent. "Many individuals show great resilience (恢复力，弹性)," he says.
Stephen Wood, who studies adolescent development at the Melbourne
Neuropsychiatry Centre in Australia, says the brain abnormalities cannot
necessarily be blamed on children’s relationship with their parents. He points
out that the subjects studied may have been born with the abnormalities and as a
result didn’t bond well with their parents, rather than vice versa. Wood also
takes issue with the study team’s decision to exclude individuals with low
socioeconomic status and uneducated parents two factors known to contribute to
poor performance in cognitive tests. "The effect they found may be real, but why
worry about parenting if there are other factors that are so much larger" he
says. If parents are overprotective or neglectful, children are ______.