Two physical fights can destroy a teenagers IQ to the equivalent of losing a whole year of school, researchers from Florida State University reported in the Journal of Adolescent Health. For girls, a similar loss of IQ is possible after just one fight.
The researchers say the findings of their study are significant, because falls in IQ are linked to lower academic and professional performance, behavioral problems, mental disorders, and decreased lifespans.
Joseph A. Schwartz, a doctoral student who carried out the study with Professor Kevin Beaver in FSU’s College of Criminology and Criminal Justice, said:
“It’s no surprise that being severely physically injured results in negative repercussions, but the extent to which such injuries affect intelligence was quite surprising.”
Schwarts and Beaver claim that their study, titled “Serious Fighting-Related Injuries Produce a Significant Reduction in Intelligence”, is among the very few to examine the long-term consequences of fighting during a child’s teenage years.
Several studies have linked some contact sports with brain injuries, lower IQ and neurological problems. Even frequently heading a soccer ball has been shown to increase the risk of brain injury.
Adolescence is a critical period in neurological development.
Each year, approximately 1 in every 20 high school students is injured because of a physical fight, the authors wrote.
Beaver and Schwartz wanted to determine what impact serious fighting-related injuries might have on IQ over a five-to-six year time span. They gathered and examined data from the National Longitudinal Study of Adolescent Health (1994-2002).
In this longitudinal study, 20,000 middle and high school children were periodically monitored until they were adults. The authors described the sample population as “a nationally representative” one.
Each time they were monitored, the participants answered questions regarding their social relationships, frequency of specific behaviors and personality traits.
The researchers were not surprised to find that teenage boys got into considerably more physical fights than girls of the same age. However, physical injuries from fights affected girls’ IQs much more than boys’.
The investigators attributed this to the “physiological differences that give males an increased ability to withstand physical trauma.”
The study found that each fight-related injury resulted in:
- A drop of 1.62 IQ points for boys
- A fall of 3.02 IQ points for girls
These figures were calculated after the authors had controlled for changes in race, age, and status.
According to previous studies, missing a whole academic year is equivalent to a loss of between 2 and 4 IQ points.
When the researchers just looked at head injuries from fights, the impact on IQ was even greater.
Beaver said that communities and schools need to develop policies aimed at minimizing injuries suffered during a child’s teenage years through contact sports, bullying or fighting.
“We tend to focus on factors that may result in increases in intelligence over time, but examining the factors that result in decreases may be just as important.
The first step in correcting a problem is understanding its underlying causes. By knowing that fighting-related injuries result in a significant decrease in intelligence, we can begin to develop programs and protocols aimed at effective intervention.”