The Fatal Relationship Between Firearm Policy and Brain Development

By Vincent A Medina

Gun deaths in the United States far exceed those of every other developed country in the world (Sam & Rupp, 2022). This has prompted frequent discussions about public policy change. Much of the dialogue as it relates to psychology has focused on mental illness, as it is relatively easy for individuals in the United States with serious mental illnesses to pass background checks and legally purchase guns (Philpott-Jones, 2018). Calls to limit firearm access for those of unsound mind are certainly of great importance. However, perhaps there is also a need to discuss how firearm policy relates to the natural development of the human brain. Federal law states that the minimum age for purchasing firearms is 18. According to Everytown Research & Policy (2022), fourteen states have raised the minimum age to 21 for handguns specifically, and fewer than half of the fifty states have raised the age for firearms across the board. Regardless, all of the above age requirements are inadequate given that the brain undergoes dramatic developments—also known as adolescence—until the age of 24. Incomplete cognitive control has dire consequences when paired with firearms, so the minimum age for civilian firearm use should be raised to at least 25.

According to the World Health Organization (2022), adolescence is the age range of 10-19. However, researchers studying human development have defined it as the age range of 10-24 (Arain et al., 2013; Berman et al., 2009; Sawyer et al., 2018) with respect to the time course of structural brain changes. That is, brain development is incomplete until the age of 24, particularly for the prefrontal cortex (Casey et al., 2008). The prefrontal cortex is a region of the brain responsible for executive function, which consists of a range of important skills involved in cognitive control. Examples of such skills include inhibiting one’s actions, weighing the consequences of behavior, exercising self-control, and engaging in long-term thinking (Fuster, 2019; Steinberg, 2005).

Neuroimaging work has shown that the limbic system (a group of structures consisting of the amygdala, hippocampus, and hypothalamus that is chiefly involved with emotions) is used more than the prefrontal cortex by adolescents because of a maturation mismatch: during adolescence, the prefrontal cortex is still developing while the limbic system is already mature (Arain, 2013; Giedd, 2015). Greater reliance on the “emotional” limbic system instead of the “logical” prefrontal cortex can explain why individuals below the age of 25 are prone to behaviors that older individuals would consider inappropriate or dangerous (Arain et al., 2013; Giedd, 2015). This maturation mismatch aligns with the pattern of the deadliest mass shooters in recent history falling into the age range of 18-24 (Cha et al., 2022). Take, for example, the individuals responsible for the incidents at Robb Elementary School (age 18), Stoneman Douglas High School (age 19), Sandy Hook Elementary School (age 20), and Virginia Tech (age 23). To put it plainly, 18-24 is the critical age range where individuals can legally access guns in the United States, but are still more vulnerable than the average adult to giving into negative emotions (e.g., anger or despair) while their cognitive control skills are still immature. To account for this, federal policymakers need to set the age requirement for purchasing firearms to at least 25.

Some nations do not set minimum age requirements for gun ownership to at least 25, but do pair their minimum age requirements of 18 with different, more stringent conditions (Lopez, 2018). Canada requires licenses that must be renewed every five years, as well as safety courses, third-party character references, and safe gun storage to prevent theft or unlicensed use. The United Kingdom requires licenses that must be renewed every five years, a “good reason” for purchase beyond self-defense, and has a general ban on handguns and military-grade firearms. Japan, which has some of the strictest gun restrictions in the world, requires a rigorous license (that includes a mental health test, physical test, written test, and drug test) that must be renewed every three years, a separate permit for ammunition purchase, documentation of gun storage location that is open to random inspection by authorities, annual inspection of the firearm by authorities, an agreement to surrender the firearm to authorities in the case of an unrelated public incident, and has a general ban on handguns.

While there is no example of other countries setting the minimum age requirement to 25, it is clear that more restrictive policies are associated with less lives lost to gun homicides. While adopting other national policies is certainly one approach and addressing topics in the field of clinical psychology (i.e., mental illness treatment, detection regarding firearm access) are certainly another, a more stringent minimum age requirement guided by the brain development literature could save many lives in the United States in particular. This is because approximately 30% of all mass shootings in the country since 1982 have been perpetrated by individuals below the age of 25 (Follman et al., 2022). This paints an urgent picture when combined with the fact that the deadliest mass shootings in recent history have also been carried out by individuals below the age of 25 (Cha et al., 2022). Bearing all of the above in mind, new policy raising the minimum age requirement to 25 in the United States should have great preventative impact for the future.

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Written by Vincent Medina

Illustrated by Kayla Lim

Edited by Lauren Wagner and Carolyn Amir

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References

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