New study explores connection between physical fights and long-term cognitive decline
A Florida State University study finds that fighting-related injuries during adolescence are associated with measurable drops in intelligence scores, with girls showing larger average losses than boys.
Researchers at Florida State University analyzed long-term data and report that teenagers who suffer injuries from physical fights experience significant declines in IQ over time. The study reports that boys who sustained two fighting-related injuries showed IQ losses roughly equivalent to missing an entire year of school, while girls experienced a similar reduction after just one injury. These findings raise important concerns about the lasting cognitive and social consequences of adolescent violence.
The research, published as “Serious Fighting-Related Injuries Produce a Significant Reduction in Intelligence” in the Journal of Adolescent Health, uses a nationally representative longitudinal data set to examine how serious injuries from fights affect intelligence during the critical developmental period of adolescence. The authors emphasize that even moderately sized drops in IQ are meaningful because reductions in measured intelligence are linked to lower educational attainment, diminished occupational outcomes, elevated risk of mental health problems and behavioral difficulties, and even shorter life expectancy.
To assess the long-term cognitive impact of fighting-related injuries, the researchers used data from the National Longitudinal Study of Adolescent Health collected between 1994 and 2002. That study began with an initial nationally representative sample of about 20,000 middle and high school students and followed participants into adulthood through multiple waves of data collection. At each wave, participants provided detailed information on behaviors, social relationships, personality traits and demographic factors that allowed the researchers to control for confounding influences.
Findings from the analysis indicate that boys report a higher frequency of fighting-related injuries, but the average cognitive impact per injury appears larger for girls. After controlling for socio-economic status, age and race, each fighting-related injury corresponded to an average loss of 1.62 IQ points for boys and 3.02 IQ points for girls. Prior research has estimated that missing an entire academic year is associated with a loss of roughly 2 to 4 IQ points, which provides context for the educational significance of the reported declines.
The study authors also note that their analysis included all serious injuries resulting from fights and did not isolate head trauma specifically. Because head injuries are particularly damaging to brain function, the true impact on intelligence might be larger when examining only injuries that involve the head. The current results therefore likely represent a conservative estimate of the cognitive toll of fight-related trauma during adolescence.
Approximately 4 percent of high school students report being injured as a result of a physical fight each year, according to the data used in this study. Given the prevalence of such injuries and the measured association with IQ decline, the researchers argue that schools, families and communities should prioritize prevention strategies and policies to reduce adolescent injury from fighting, bullying and contact sports. Preventive measures and effective intervention programs could help protect young people at a stage when the brain remains highly sensitive to injury.
Joseph A. Schwartz, a doctoral student, and Professor Kevin Beaver of FSU’s College of Criminology and Criminal Justice conducted the analysis. “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,” said Schwartz. The authors contend that focusing not only on factors that increase intelligence but also on those that cause decreases is essential for designing public health and educational responses.
By identifying and documenting the cognitive consequences of fighting-related injuries, the study aims to inform the development of targeted programs and school-level protocols for prevention and intervention. Early recognition and mitigation of risk factors, combined with policies that reduce exposure to physical violence, may help preserve cognitive development and improve long-term educational and social outcomes for adolescents.
Notes about this neuropsychology research
Contact: Kevin Beaver – Florida State University
Source: Florida State University press release
Image Source: Fist image credited to Flickr user Richard North, licensed as Creative Commons Attribution 2.0 Generic
Original Research: Abstract for “Serious Fighting-Related Injuries Produce a Significant Reduction in Intelligence” by Joseph A. Schwartz and Kevin M. Beaver, Journal of Adolescent Health. Published online July 26, 2013. DOI: 10.1016/j.jadohealth.2013.06.007