Under the M'Naghten standard, the defendant did what?

• A. The person did not know the act was wrong
• B. The person could not control conduct
• C. The person lacks substantial capacity to know the act was wrong
• D. The act was committed under irresistible impulse

Answer: (A)

This item tests the insanity defense standard used in criminal law. Under the M'Naghten rule, a defendant is not responsible for criminal conduct if, due to a mental disease, they did not know what they were doing or did not know that what they were doing was wrong. The statement that best fits this standard is that the person did not know the act was wrong, since M'Naghten focuses on knowledge of wrongfulness (or knowledge of the nature and quality of the act).

The other ideas reflect different insanity standards: inability to control conduct corresponds to a volitional incapacity or irresistible-impulse test, which M'Naghten does not require; lacking substantial capacity to know the act was wrong aligns with the Model Penal Code test, which centers on substantial lack of capacity rather than outright knowledge of wrongness.