Posted by: R. Douglas Fields | October 30, 2010

Sticks and Stones–Hurtful words damage the brain

 
 
 
 
 

Verbal abuse by peers damages a child's brain

 

            Sticks and stones may break my bones, but words will never hurt me…  We all know how untrue that childhood incantation is.  Words do hurt.  Ridicule, distain, humiliation, taunting, all cause injury, and when it is delivered in childhood from a child’s peers, verbal abuse causes more than emotional trauma.  It inflicts lasting physical effects on brain structure.

            The remarkable thing about the human brain is that it develops after birth.  Unlike most animals whose brains are cast at birth, the human brain is so underdeveloped at birth that we cannot even walk for months.  Self awareness does not develop for years.  Personality, cognitive abilities, and skills, take decades to develop, and these attributes develop differently in every person.  This is because development and wiring of the human brain are guided by our experiences during childhood and adolescence.  From a biological perspective, this increases the odds that an individual will compete and reproduce successfully in the environment the individual is born into, rather than the environment experienced by our cave-man ancestors and recorded in our genes through natural selection.  Developing the human brain out of the womb cheats evolution, and this is the reason for the success of our species.

            When that environment is hostile or socially unhealthy, development of the brain is affected, and often it is impaired.  Early childhood sexual abuse, physical abuse, or even witnessing domestic violence, have been shown to cause abnormal physical changes in the brain of children, with lasting effects that predisposes the child to developing psychological disorders.  This type of brain scarring is well established now by human brain imaging studies, but prior to the recent study by Martin Teicher and colleagues at Harvard Medical School, taunting and other verbal abuse experienced by middle school children from their peers was not thought to leave a structural imprint on the developing brain.  But it does, according to their new study published on-line in advance of print in the American Journal of Psychiatry

            Young adults, ages 18-25, with no history of exposure to domestic violence, sexual abuse, or parental physical abuse, were asked to rate their childhood exposure to parental and peer verbal abuse when they were children, and then they were given a brain scan. 

            The results revealed that those individuals who reported experiencing verbal abuse from their peers during middle school years had underdeveloped connections between the left and right sides of their brain through the massive bundle of connecting fibers called the corpus callosum.  Psychological tests given to all subjects in the study showed that this same group of individuals had higher levels of anxiety, depression, anger, hostility, dissociation, and drug abuse than others in the study. 

            Verbal abuse from peers during the middle school years had the greatest impact, presumably because this is a sensitive period when these brain connections are developing and becoming insulated with myelin.  (Myelin is formed by non-neuronal cells, brain cells that are also known as “the other brain”, or glia.) 

            The environment that children are raised in molds not only their mind, but also their brain.  This is something many long suspected, but now we have scientific instruments that show us how dramatically childhood experience alters the physical structure of the brain, and how sensitive we are as children to these environmental effects.  Words–verbal harassment–from peers (and, as a previous study from these researchers showed, verbal abuse from a child’s parents) can cause far more than emotional harm. 

            Early childhood experience can either nourish or stifle brain development, and the consequences are physical, personal, and societal.             Childhood taunting and verbal bullying have always been a problem, but many feel that civility, courtesy, polite social interactions, have declined markedly from the environment that today’s adults experienced as children.  Many schools are more hostile places than schools once were, and new technologies, such as the internet, offer more opportunities for taunting and humiliation of children.  If this is true, modern conditions or attitudes that tolerate verbal abuse of children by their peers are an incubator for developing brains with abnormalities in the corpus callosum and an elevated risk of psychiatric problems.  The critical concern for ridding our environment of neurotoxins must also include “neurotoxins” children are exposed to in their social environment.

 

            (Note:  for new research showing an impaired ability to make moral judgments in people with defects in the corpus callosum connecting the left and right sides of their brain, see http://www.huffingtonpost.com/dr-douglas-fields/of-two-minds-on-morality_b_738916.html.)

 

Photo credit:  dailymail.co.uk

 

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Responses

  1. ‘Develop to the mode of statistical norm within a given population’ may be more accurate than referring to certain brains as damaged.

    Indeed. Interesting article … from a Cyrushansonian perspective.

  2. It would be interesting to know how a girl’s brain is affected by the kind of exclusion and clique-formation that middle-school girls engage in rather than overt verbal abuse. They use more subtle ways to put outsiders down and make them feel inferior. Come to think of it, many women do the same in adulthood!

  3. How can we be certain the bullying is causing the abnormal brain development and not vice versa? For example, a high-functioning autistic child, or even just a child unusually inclined to introspection, melancholia etc, is surely more likely to be bullied?

    • Mike, This is certainly possible, because this was a retrospective study. Children who are in any way “different” can find themselves bullied. The authors discuss this alternative hypothesis. To test it, future research will have to be done using a “longitudinal” experimental design; i.e., following children over time rather than looking back.

      • Thanks for that clarification. I will be interested to see how this one develops. By the way, I found this blog after hearing your interview on the Brain Science Podcast from last year – the book sounds fascinating, will have to order it!

        Thanks, Mike


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