By Megan Olden, published on May 1, 2003 - last reviewed on April 10, 2007
Sibling animosity may be a universal truth, but that doesn't mean
it is well understood. In a first attempt to link behavioral problems in
early adulthood to the relationship with a brother or sister, researchers
found that boys with older siblings who were critical of them were more
likely to be arrested or to abuse drugs and alcohol.
In the study, 20-year-old boys with older siblings who had negative
attitudes toward them were also more likely to associate with deviant
peers and have sexual intercourse at a younger age than were boys with
noncritical siblings. They exhibited the same antisocial behavior two
The study, published in the Journal of Family Psychology (2003), required
73 men and women to describe their relationship with a younger brother.
These findings do not imply that criticism causes deviance: Indeed, the
siblings could have been highly critical because their brothers' behavior
was problematic. But they do illustrate the potentially harmful impact of
sibling interaction, says Bernadette Bullock, Ph.D., a research scientist
at the University of Oregon's Child and Family Center and co-author of
"Sibling influence is part of an ongoing multidirectional dynamic,"
says Bullock. The relationship is in turn influenced by parental
attitudes and each child's temperament.
Jeanne Safer, Ph.D., a psychoanalyst and author of The Normal One:
Life With a Difficult or Damaged Sibling, agrees: "How siblings relate to
one another very often has to do with how the parents see the siblings
and create the relationship between them."
Researchers including Bullock are now exploring the associations
between parental and sibling attitudes, including the possibility of a
contagion effect, in which the opinions of one family member affect the
perceptions of others in the home.