When Marion Bowman was arrested at age 20 for the murder of Kandee Martin, society did not consider him mature enough to drink alcohol, rent a car, or enter a casino. Yet he was deemed old enough to be sentenced to death. Now 44, he has spent over half his life on South Carolina’s death row and is scheduled for execution on January 31. “Retribution is not proportional if the law’s most severe penalty is imposed on one whose culpability or blameworthiness is diminished, to a substantial degree, by reason of youth and immaturity,” the United States Supreme Court reasoned when it prohibited the death penalty for criminal defendants under the age of 18 in Roper v. Simmons (2005). A growing body of neuropsychological research has found that the same deficits in critical thinking, impulse control, and susceptibility to peer pressure that motivated the Roper Court to exempt juveniles from execution also apply to “emerging adults” aged 18 – 20. And evidence suggests that the death penalty is disproportionately applied to youthful Black offenders like Mr. Bowman, who if his execution proceeds will become the fifth Black prisoner in South Carolina put to death in the modern era for a crime committed under age 21 — compared to just one white prisoner.
Emerging Adults Experience Same Neurocognitive Deficits as Juveniles
The Constitution limits the death penalty to offenders who commit “a narrow category of the most serious crimes” and “whose extreme culpability makes them the most deserving of execution.” In Roper, the Supreme Court held that juveniles were less culpable because of their diminished capacity to control their behavior. Justice Anthony Kennedy, writing for the majority, relied on scientific studies that highlighted juveniles’ “lack of maturity and underdeveloped sense of responsibility, [which] often result in impetuous and ill-considered actions and decisions”; noted that they are “more vulnerable or susceptible to negative influences and outside pressures, including peer pressure”; and argued that “the character of a juvenile is not as well formed as that of an adult,” making rehabilitation a greater possibility.
Mr. Bowman’s case demonstrates several common elements of youthful offenses. He was convicted and sentenced to death for the murder of Ms. Martin, age 21, in connection with a drug-dealing dispute. Three other young people were arrested as participants, and according to Mr. Bowman’s defense team, “the only alleged eyewitness confessed to committing the murder himself.” Mr. Bowman has maintained his innocence. “I regret the role I had in dealing to Kandee and know that her addiction probably led to her death. But I did not do this,” he said in a written statement.
The past two decades of neuropsychology and human development research have revealed that emerging adults share the key brain function characteristics with juveniles that formed the basis of Roper. The sensation-seeking and reward-seeking features of the brain develop during puberty, but the “cognitive control system” that regulates impulses, promotes long-term planning, and resists peer pressure does not fully develop until around age 25. In 2018, the American Bar Association called for the prohibition of the death penalty for “any individual who was 21 years old or younger at the time of the offense,” referring to the “growing medical consensus that key areas of the brain relevant to decision-making and judgment continue to develop into the early twenties.”
