Chapter 9 Outline

To successfully prosecute a case, the prosecutor must prove that the defendant committed the guilty act (actus reus) intentionally and with a guilty mind (mens rea)
Affirmative defense: One in which the act is admitted but a guilty mind denied, and include justification defenses (self-defense, victim consent, execution of public duties) and excuse defenses which include duress, age, or the presence of a rationality defect (essentially, legal insanity or mental disability) at the time when the offense was committed, and the burden of proof is on the defense
Exoneration: Official legal relief provided to someone from the burden of responsibility, obligation, or punishment and exoneration occurs when a person convicted of a crime is later deemed to be innocent
DNA evidence is used overwhelmingly in issues of guilt and innocence
Brain imaging is used solely to address issues of mitigation

The issue that now dominates abolitionist arguments is innocence which has influenced public opinion

Some scholars feel that if the “hard” evidence of science is accepted uncritically by the courts, it will undermine traditional ideas of justice because it undermines traditional ideas of human responsibility
MAOA is an enzyme responsible for breaking down neurotransmitters (chemicals that send messages between brain cells), particularly serotonin. Serotonin levels are involved in emotion and mood, such as depression, impulsivity, and problems with anger control
The MAOA gene is the gene most frequently used (although still extremely rare) as a mitigating factor in murder cases
The MAOA mitigation claim saved David Bradley Waldroup’s life. The jury convicted him of voluntary manslaughter instead of first-degree murder because he possessed the MAOA-L gene and had a childhood history of abuse

Gene: A segment of deoxyribonucleic acid (DNA) that codes for a protein. They make protein which is the stuff that builds, maintains, and replaces the tissues in our bodies
DNA is found on our chromosomes
Allele: An alternate form of the same gene. You get one allele of a gene for a given trait from your mother and another from your father

Polymerase chain reaction (PCR): A technique used to greatly amplify the number of copies of a DNA sample from a crime scene to get enough copies for testing

Magnetic resonance imaging (MRI) shows the anatomical structure of the brain, and will inform us if certain parts of the brain contain tumors, are damaged or atrophied, or have some other structural impairment as a result of injuries or infections
Functional magnetic resonance (fMRI) allows us insight to the functioning of the brain in real time. This procedure uses the blood-oxygen-level-dependent (BOLD) contrast

There are physical reasons why adolescents do not show the same level of rational judgment that adults do and why they tend to assign faulty attributions to situations and to the intentions of others
In the mid-20s, the brain reaches its adult state and more adult-like personality traits emerge, such as becoming more conscientious and agreeable and less irritable and neurotic
Neuroscience has shown us that a lower level of culpability attaches to juvenile offenders
In Roper Simmons (2005), brain immaturity was a major factor in ruling juvenile death penalty sentences unconstitutional

The advocacy of DNA as some sort of truth device is a double-edged sword—if it can be used to exonerate the innocent with apparent certitude, it can be used to condemn the guilty with the same apparent certitude
A number of police labs have been accused and found guilty of falsifying and fabricating DNA while others have been shown to be incompetent in their use of PCR and interpreting results, and to have cross-contaminated and mislabeled sample DNA

fMRI results emerge from data averaged over a group of subjects; they are problematic when applied to specific individuals
Ecological fallacy: A mistake in logic made when one makes an inference about individuals deduced from aggregate statistical data derived from the group to which he or she belongs
Imaging of offenders’ brains is typically performed many years after the crime was committed. Today’s brain is not yesterday’s brain, and the images jurors may see in court may be vastly different from what they may have seen shortly after the crime for which the defendant is seeking mitigation
Scanning tells us the probable state of the subject’s mind at the time of the scan; it cannot settle matters of legal responsibility

BOX 6.1 Neuroimaging a Psychopathic Serial Killer: A Case of Successful Exoneration and Failed Mitigation

Brian James Dugan was one of the worst psychopaths ever diagnosed with the condition and his brain imaging showed all the signs of He murdered and raped three females, was given the death penalty even after a neuroscientist testified that he was a psychopath. Illinois Governor Pat Quinn abolished the death penalty in March 2011 and Dugan’s sentence was commuted to life if prison
Classic psychopathy signs show the inability to “tie” the brain’s emotional and rational sides together, and a relatively inactive amygdala, the part of the brain that deals with emotions, particularly fear
The inability to engage the emotions typically means that the person will lack empathy, shame, and guilt, and will thus be callously indifferent to the suffering of other
A relatively inactive amygdala signals a relative lack of fear, which leads psychopaths to take risks that most other people would not