Mental states that determine the degree of guilt or culpability in criminal law are generally classified from highest (most worthy of blame or punishment) to lowest as: (1) intentional; (2) knowing; (3) reckless; and (4) criminal negligence.

A person acts with criminal negligence, or is criminally negligent, with respect to circumstances surrounding his conduct or the result of his conduct when he ought to be aware of a substantial and unjustifiable risk that the circumstances exist or the result will occur. The risk must be of such a nature and degree that the failure to perceive it constitutes a gross deviation from the standard of care that an ordinary person would exercise under all of the circumstances, as viewed from the accused person’s standpoint at the time of the alleged criminal negligence.

Criminal offenses or crimes often specify the culpable mental state the prosecution is required to prove to convict a defendant of the offense. These culpable mental states are generally defined in the relevant state or federal statutes—usually in the penal or criminal code.

In Iowa, as in many jurisdictions, the mental state of an individual plays a crucial role in determining their degree of guilt or culpability in criminal law. These mental states are often referred to as 'mens rea' and are categorized from most to least blameworthy as follows: intentional, knowing, reckless, and criminal negligence. Intentional actions are those committed with the purpose of causing a particular result, while knowing actions are those where the individual is aware that their conduct is almost certain to cause a result. Reckless behavior involves conscious disregard of a substantial and unjustifiable risk, and criminal negligence occurs when an individual fails to perceive a substantial and unjustifiable risk that their conduct may cause a certain result, which represents a gross deviation from the standard of care an ordinary person would exercise. In Iowa, these mental states are defined within the Iowa Code, and for a conviction, the prosecution must prove that the defendant acted with the requisite level of culpability as specified by the statute for the particular offense.