Glossary

And it succeeds even less often. Most people picture it as a loophole. In reality, it is rarely attempted and rarely works.

An almond-shaped structure deep in the brain that processes emotions, especially fear and threat responses. In high-stress situations it can override rational thinking and is relevant to how courts evaluate behavior under extreme duress.

A person with specialized knowledge such as a forensic psychiatrist or neurologist who is permitted to offer professional opinions in court, not just facts. Their testimony often bridges the gap between science and the law.

Neuroscience shows that memory is a reconstruction, not a recording. Every time you recall something, you slightly rewrite it. Courts are still catching up to this fact.

A set of mental skills that includes working memory, flexible thinking, and self-control. Deficits in executive function are central to many forensic psychiatry evaluations.

In Roper v. Simmons (2005), the Court used brain development research as part of its reasoning that executing someone for a crime committed before age 18 is unconstitutional.

A legal standard requiring that a defendant understand the charges against them and be able to participate in their own defense. A person can be found not competent due to severe mental illness and may be sent for treatment before trial proceeds.

The front region of the brain that handles planning, decision-making, impulse control, and understanding consequences. It is the last part of the brain to fully develop, typically finishing around age 25.

A tool called COMPAS was used in U.S. courts to predict whether a person would reoffend. An investigation by ProPublica found Black defendants were flagged as high-risk at nearly twice the rate of white defendants with similar records.

Evidence presented during sentencing that does not excuse a crime but may reduce the punishment. Brain damage, trauma history, and intellectual disability are examples that often involve neuroscience testimony.

A chemical messenger that carries signals between nerve cells in the brain. Imbalances in neurotransmitters like dopamine and serotonin are linked to conditions that frequently appear in criminal cases, including schizophrenia, bipolar disorder, and depression.

A legal argument that a defendant should not be held criminally responsible because, at the time of the crime, a mental disease or defect prevented them from understanding what they were doing or knowing it was wrong.

The prefrontal cortex is the part responsible for judgment, impulse control, and weighing consequences and is the last region to mature. This fact changed how the U.S. Supreme Court sentences young people.

The brain's ability to change and reorganize itself by forming new connections throughout life. Trauma, learning, and environment can all reshape the brain's structure.

Latin for "guilty mind." Most crimes require not just a harmful act but the intent to commit it. This is why mental state is so central to criminal law and why neuroscience is increasingly relevant in court.