The Brain Locked Up: Neuroscience and the Criminal Justice System

Introduction

Since the 1970s, the population of U.S. prisons and jails has increased 500%, giving the country the highest incarceration rate in the world [1] [2]. This staggering statistic points to a problem, and with almost two million Americans living in prisons and jails today, it is imperative to evaluate the criminal justice system through a lens of modern science [3]. Recent studies in psychology and neuroscience have elucidated the court and prison systems’ devastating effects on brain functioning, as well as the way that biases and prior trauma play into these processes. However, this research often remains unacknowledged in government and politics - the spheres where this evidence could have a real impact. By demonstrating how different parts of the criminal justice system affect the individuals involved, psychology and neuroscience research plays an essential role in shedding light on specific issues within correctional institutions and guiding changes in policy that would lessen their negative impacts. 

Courts 

Long-term involvement in the criminal justice system begins in the court, an institution created to bring justice to victims of crime, but that at times fails to do so. Despite their commitment to fairness and objectivity, U.S. courts are notorious for their bias, part of which comes from their reliance on eyewitness testimony. Humans are innately unreliable narrators; eyewitness testimony contributes to almost 30% of cases of false imprisonment where an individual is cleared of a crime from DNA evidence after they have already been convicted, and this rate increases to almost 70% when looking at sexual assault charges alone [4]. Bias in eyewitness testimony results from the brain’s inability to accurately process memories during high-stress situations [5]. However, this bias is an unconscious process – the eyewitness is not aware that they have these biases and may still feel confident in their inaccurate testimonies, which can tremendously sway a jury’s decision [6]. 

In addition to eyewitness testimony, some investigative techniques do not withstand scientific testing despite their effect on the outcome of criminal trials. For example, polygraph tests, otherwise known as a “lie-detector” test, have been the primary method of gathering evidence of deception, but their reliability is still highly debated and can range anywhere from 50% to 90% accuracy [7]. During a polygraph test, an individual is connected to sensors, which detect heart rate, breathing rate, sweat, and other physiological and neural signs of fear or stress that might indicate deception [8]. However, signs of deception are not consistent in every individual and may even be caused by anxiety from the questioning process alone, making the use of polygraphs questionable for determining truth [8]. Although they are inadmissible in court due to their inconsistency, these techniques can lead to long and cruel investigative techniques, false or coerced confessions, and subsequent unjust convictions [9] [10] [8]. 

Since the invention of the polygraph, more reliable methods of lie detection have come into play due to the contribution of neuroscience, such as functional magnetic resonance imaging (fMRI) [7]. Brain areas called the frontal and parietal cortex, located at the front and sides of the brain, are activated when an individual is lying. By tracking the subtle changes in blood flow to these areas, fMRI can detect this activation with 80%-90% accuracy in determining if a person is being deceptive [11] [7]. Although fMRI still has limitations, such as cost and practicality, funding for and promotion of more modern neuroscientific techniques like this may significantly decrease wrongful convictions and lead to a fairer court system.

Corrections

After courtroom proceedings, the next step for many involved in the criminal justice system is serving time in prison or jail. Recent neuroscience research has revealed that the prison environment – where one is deprived of visual and auditory stimulation, social interaction, and stress relief methods – can have a negative impact on the brain and its ability to function normally [12] [13]. Studies have found that prolonged imprisonment can weaken one’s executive functioning skills, which include but are not limited to, attention, memory, problem-solving, and emotional and behavioral regulation [12] [13]. Decreased executive functions can increase the risk of recidivism – meaning additional arrests in the future – as well as exacerbate the difficulty of obtaining a job upon release [13]. 

In addition to the effects of the daily prison environment, common punishments for breaking prison rules can worsen these effects or have added consequences for inmates. The most prominent example of this is the practice of solitary confinement, in which an individual is disciplined by being isolated to a single cell and excluded from all contact with other prisoners. Solitary cells are even more deprived of stimuli than the ordinary prison environment as they contain only a bed and toilet and have no aspect of socialization, and therefore can have an even greater impact on the aforementioned executive functioning skills [14]. Solitary confinement also has a profound effect on inmate mental health [15]. The punishment has been shown to exacerbate symptoms of existing mental illness, as well as bring on new symptoms of depression, anxiety, guilt, loss of identity, distorted sensory processing, and even self-harm [15].

Aside from the cognitive and emotional consequences that may be sustained inside of prisons and jails, there is also a large, disproportionate percentage of incarcerated individuals who enter these environments with pre-existing mental health conditions. This stems from the deinstitutionalization movement of the 1960s, when activists advocated for the closing of state psychiatric hospitals in order to provide more humane care to those with mental health disorders and disabilities [16]. However, due to the lack of community-based care options, such as outpatient therapy or support groups, this movement led to the mass incarceration of former patients and exponentially increased the number of mentally ill prisoners [16]. 

Today, almost half of incarcerated individuals – over one million people – suffer from at least one diagnosed mental illness [17]. Of these individuals, 29% are considered to have “serious” mental illnesses, including bipolar disorders, depressive disorders, and psychotic disorders [17]. However, almost two-thirds of these individuals did not receive treatment for these illnesses while incarcerated, and 40-50% of those taking psychiatric medication before incarceration report not having access to these medications in prisons and jails [18] [19]. This can lead to a relapse of symptoms, increasing the risk of violating prison rules due to the mental strain these mental illnesses cause [20]. In turn, violation of these rules leads to punishments like solitary confinement that may further stress the mind and brain, creating a cycle of trauma [20]. 

Unfortunately, release from jail or prison does not mean the end of these struggles. Life on the outside requires taking the initiative to find housing, employment, and a new social life. However, prison’s effect on aspects of brain functioning, including attention and self-control, makes it challenging to sustain focus on these tasks, which leads to higher rates of unemployment and houselessness, as well as a high likelihood of recidivism for the formerly incarcerated [21]. Additionally, there are few resources for free mental health care, including medication, after release. For example, only 5% of inmates are referred to a community mental health team in preparation for their release, which causes many individuals to experience a relapse in symptoms once they are released from prison [22]. Changes in policy that require prisons to provide these resources to every soon-to-be-released inmate could substantially decrease rates of recidivism and assist these individuals in the stabilization of their lives post-release. 

Causes of Crime & Prevention of Trauma

Psychology and neuroscience can also help to reveal the causes of some criminal behavior and inform policy on reducing it before arrests occur. Most prominently, a large body of research has shown that individuals with many adverse childhood experiences - or ACEs - are significantly more likely to be incarcerated at some point in their lifetime than those with little to none [23]. An individual’s ACE “score” reflects how many traumatic events they have experienced out of ten categories, including physical, emotional, or sexual abuse; emotional or physical neglect; and growing up with mental illness, domestic violence, divorce, incarceration, or substance abuse present in the household [24]. 

ACEs and other kinds of trauma have a direct impact on the way an individual produces and responds to cortisol. Cortisol is a hormone normally released into the bloodstream during stressful events to trigger the “fight or flight” response, telling the body to either stay and fight the danger or run away from it [25]. ACEs can lead to both increased or decreased cortisol production and sensitivity depending on the type of trauma experienced [26]. If the stressful event comes on suddenly and ends quickly, cortisol levels may remain increased, and the individual will react as if they are consistently in danger [26]. However, if the trauma is long-lasting and occurs repeatedly, the body may build a tolerance to constant surges of cortisol and react less strongly to it when it is needed, even after the trauma is over [26]. Additionally, because of cortisol’s additional role in heart health and the immune system, ACEs can increase the risk of chronic health issues and can decrease life expectancy by up to twenty years [27]. 

While the CDC estimates that only 17% of the U.S. population has four or more ACEs, some studies have found that this percentage jumps to 45% in incarcerated populations [28][29]. Other traumatic experiences that are not included in the ten ACEs categories, such as bullying and community violence, also occur at vastly disproportionate rates in incarcerated populations [23]. This is, in part, due to the constant state of biological stress from the production of cortisol and the chronic illness it can lead to over time [30][31].

By changing attitudes and social norms surrounding violence, fostering community within families and communities, and improving economic and educational outlooks for populations in which ACEs are most common, these traumas can be prevented for future generations [32]. Additionally, all hope for recovery is not yet lost for those who have already experienced these traumas. Once ACEs occur, there are many methods that work to repair the damages that they incur, not only through therapy but also through nutrition, sleep, and mindfulness that can help reduce stress and therefore improve physical and mental health [33]. Implementing policies that work to combat the systemic issues that contribute to the risk of ACEs - whether in economics, education, or law enforcement - could help lower the overall prevalence of trauma. Creating or expanding policies in healthcare access and increasing funding for programs that work to spread awareness of various treatment options could also have a drastic effect on the population of prisons and the future prospects of those who previously experienced ACEs as well. 

Conclusion

With these new research findings, neuroscience has the chance to eliminate bias in court procedures, propel the criminal justice system into a new era of recovery and reentry, and reduce the exponentially rising rates of imprisonment and recidivism before they ever occur [34]. It is essential that everyone working in law enforcement and U.S. courts educate themselves on the impact of ACEs and prison experiences on the brain in order to mold the system to foster empathy and rehabilitation [35]. By using psychological and neuroscientific evidence to advocate for policy changes regarding bias, trauma, and mental health, the U.S. can ensure that impartial justice and healing become a permanent fixture in criminal justice.

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