Insanity Defense:
The insanity defense is asserted when a criminal defendant has been charged with a crime that of which the defendant admitted that they have committed, but lacks culpability based upon impairment from mental illness (Cornell Law). For a defendant to plea insanity, they “must prove to the court that they didn’t understand what they were doing; failed to know right from wrong; acted on an uncontrollable impulse; or some variety of these factors” (FindLaw). Whether or not the defendant is guilty or not guilty by reason of insanity, the courts use one or more of the following tests to determine legal insanity: The M’Naghten Rule, The Irresistible Impulse Test, The Durham Rule and The Model Penal Code Test (FindLaw). Based upon the results of these tests can result in a successful defense as well as capacity evidence, volitional control and mental disease evidence (Knoll & Resnick).
Although there are tests to determine legal insanity, there is a demographic of people that are often acquitted based upon insanity. The demographic of individuals acquitted from insanity show that “the average defendant is male, between the ages of 20 and 29, unmarried, unemployed, minimally educated and has been acquitted for a violent offense and diagnosed with a major mental illness based upon prior contact with both the criminal and mental health systems” (Lymburner & Roesch). The presence of a mental disease that renders the defendant’s mental capacity of meeting legal criteria for responsibility plays a relevant role in determining criminal responsibility (Lymburner & Roesch).
Research provided by Lymburner & Roesch (1997) shows that defendants who are not criminally responsible by reason of insanity were diagnosed with psychotic disorders, many of which were schizophrenics. To dive deeper into the realm of disorders, more than 62% of acquittees were diagnosed with psychotic disorders, 7% with a major affective disorder, 10% were found to have a schizoaffective disorder, 4% were suffering from delusional disorder, 7% had organic disorder, and 10% had a primary diagnosis of personality disorder” (Lymburner & Roesch). One or more disorders may be present within an individual.
The insanity defense is similar to the diminished capacity defense in ways that both of these defenses look into the mental capacity of the defendant. The important difference between these two however, is that “pleading with the “reason of insanity” is a full defense to a crime while diminished capacity is pleading to a lesser crime” (Cornell Law).
Big Five Personality Traits in the Brain:
The Big Five represents the basic structure of all personality traits based upon openness, conscientiousness, extraversion, agreeableness and neuroticism. Through many of the categories of neurobiological methods, researchers are able to explore details of the structure and function of the brain while examining how personality is rooted deeply inside. A few of the neurological categories that has a representative correlation with personality and can be seen through brain scans are neuroimaging techniques such as MRI and fMRI, Electrophysiological techniques (EEG), surface-based morphology analysis (SBM) and positron emission tomography (PET).
Studies of neuroimaging provide supporting evidence that demonstrates the correlation between personality traits and brain structures (Li et al.). “One study has shown that agreeableness is associated with several gray matter regions, such as the superior temporal sulcus and posterior cingulate cortex, which are related to social information processing” (Li et al.). Evidence can show different traits are present within the brain through different scans.
Through neuroimaging techniques, the most prominent method in picturing personality neuroscience is magnetic resonance imaging (MRI) and functional MRI (fMRI) (Allen & DeYoung). An MRI “creates images of the brain based on the magnetic properties of different tissue types while measuring brain function and structure” (Allen & DeYoung). An fMRI relies on the “blood oxygen dependence level that indicates when different regions of the brain are more or less active” as well as showing functional connectivity through temporal pattern of activation and deactivation in different areas of the brain (Allen & DeYoung). Similar to the fMRI, electroencephalography (EEG) measures neural activity at a higher temporal resolution while recording electrical activity along the scalp (Allen & DeYoung). Next, the SBM analyzes cortical indicators of the brain through thickness, surface area, volume, mean curvature and sulcus depth that of which measures different properties of brain cortical surface morphology (Li et al.). Later on, the usage of SBM will show correlations of indicators of psychophysiological and neuropsychological relationships.
Brain Scans and the Relationship between the Big 5 and Psychopathology:
The basis of antisocial and psychopathic behavior is complex and is connected to brain structures that involves the regulation of impulsivity, emotional arousal, affect, and aggressive feelings which can be categorized under the Big 5 factors of neuroticism and openness.
“An increasing body of knowledge from brain imaging research is implicating brain abnormalities in the etiology of psychopathic and antisocial behavior, including abnormalities of the prefrontal cortex, temporal cortex, hippocampus, parahippocampal gyrus, angular gyrus, cingulate, basal ganglia, and amygdala” (Raine et al.).
Using an assessment of magnetic resonance imaging and measuring functional abnormalities of the corpus callosum through electroencephalography will present characteristics that antisocial and violent offenders may have, due to the white matter callosal radiations and interhemispheric asymmetries that are commonly found in psychopathic and antisocial groups (Raine et al.).
The corpus callosum orchestrates the regulation of attention, arousal and emotion but also for psychopathologic status (Raine et al.). The relationship between callosal measures and the dimensional measure of psychopathy show that having an “increase callosal volume was significantly associated with blunted affect, lack of remorse, no close friends, lack of social closeness, and reduced spatial ability” (Raine et al.). When looking at the structural abnormality in psychopathic antisocial individuals and understanding the relationship between the Big 5 and their risk factors for such behavior show that there is an account for a link between psychopathy and callosal structure and function (Raine et al.).
Brain Scans and their Relationship to Criminal Behavior:
Assessing the neuropsychological measures through the use of fMRI demonstrates the ability to predict future antisocial behavior based upon “impulsivity, behavioral disinhibition and the lack of restraint and consideration of consequences” (Aharoni et al.). A study presented by Aharoni et al. at the Massachusetts Institute of Technology, looked into the portion of the brain that deals with regulating behavior and impulsivity from criminal offenders to understand whether there are predictive brain functioning that may or may not lead to reoffending (Aharoni et al.). This area of the brain is known as the anterior cingulate cortex (ACC).
The results of the study showed that criminals who reoffended were more likely to have lower activity seen in the anterior cingulate cortex of the brain (Aharoni et al.). The anterior cingulate cortex is associated with error processing, conflict monitoring, response selection, and avoidance learning. Seen on an MRI, the anterior cingulate cortex may give an explanation as to why that part of the brain may not be working correctly and gives a deeper understanding as to who is more likely to demonstrate impulsive behaviors that could lead to re-arrest (Aharoni et al.).
Another area of the brain that can predict criminal behavior is the amygdala. The amygdala is inside of the temporal lobe of the brain and functionally involves emotions particularly controlling fear, anger and pleasure. “The amygdala has received considerable attention, with numerous studies association psychopathy with abnormal size, shape, or activity of this subcortical structure that associates with structural and functional deficits” (Koenigs).
Even though neuroscience has developed immensely throughout the years, predicting criminal behavior through scans can produce a reverse-inference error. “The reverse-inference error is especially prevalent in the interpretation of brain activity in functional neuroimaging studies” (Choi). As previously stated, the reliance of electroencephalogram data may show the activity within the brain, but depending on the section, the brain may be overactive during such time. When looking at an individual’s amygdala that is characterized as abnormal and overactive can be argued to the point of reverse-inference error due to trying to distinguish what is a normal or abnormal sign of the brain’s fear center (Choi).
Brain Scans Versus Self-Report:
Brain scans provide more complexity to detect brain impairments in individuals despite a clinical psychologist’s findings. A common problem within neurolaw is the group to individual inference problem. Psychologists often identify associations of brain defects with impairments by comparing a group of subjects with a localized defect to a group of subjects without the defect; this can result in overlapping due to the idea that impaired patients may have better control over a specific area in regard to the healthy controls and vice versa (Choi).
The issue with psychological based evidence is that very few neuroimaging-based tests are used in psychiatric diagnosis which lacks the sufficient sensitivity and specificity to be reliable enough for inclusion in diagnostic criteria” (Choi). When looking at the defendants self-reporting of their behavior, brain scans often reveal more than those reports suggest. “While most people’s self-reports are not very accurate, they do not realize their self-reports are wrong so often in predicting future behavior. The brain seems to reveal something important that we may not even realize” (University of California).
Jurors understanding of neuroscientific evidence is based upon whether they make a connection through the aforementioned evidence about the person’s criminal culpability (Kuersten). “Increasing the understanding of the pathology of the brain and the structural insights provided by technologies such as MRI have assisted both prosecution and defense in establishing degrees of harm cause” (Catley & Claydon). When presenting an individual’s criminal liability within the courts, the mental state and capacity of such individual’s brain should include neuroimaging and informative presentations to allow jurors to determine criminal responsibility (Kuersten).
Conclusion:
Based upon empirical evidence, brain scans should not be permitted in court. Neuroscience within courtrooms has been used for medical evidence or mitigating circumstances to prove that an abnormality had an effect on an individual’s behavior, however it has a lack of validated studies (Gaines).
Another issue that brain scans could produce in the courts is how the brain is defined. If the brain is defined as a piece of evidence, the use of electroencephalography could be used to incriminate such individual. Furthermore, if the brain is viewed as a testimony, the defendant has protections against self-incrimination or testifying against themselves (Gaines).
Neuroimaging techniques produce pictures of a brain at the point they are being scanned. At a criminal trial, the mental faculties that the individual possessed is at the forefront of concern. Using brain scans inside of the courtroom to determine mental guilt for a crime post-hoc provides little value. Brain scans provide integral parts of understanding the brain and provide causal links between structural or functional abnormalities, but endangers individual liberties within the Criminal Justice System from freedom of thought, invasions of privacy, self-incrimination, and due process (Kraft & Giordano).
Based upon the findings and research done on brain scans and what information comes forth, brain scans need more evidentiary and legal practice to determine whether they can be successful in courts. Through this research, brain scans have provided a strong correlation between the Big Five personality traits as well as psychopathology and how the brain is structured. Due to the fact that people are not walking around with brain scan monitors strapped to their head, using brain scans to define a guilty verdict within criminal court is going to provide little to no success in a defense all while trying to stay in the means of individual liberties.