"Reasonable person" is a legal expression used in both criminal and tort law. It refers to a theoretical person in the society who shows average judgment, skill or care in his or her conduct. Civil or criminal cases involving negligence use the reasonable person standard as the basis for comparison when deciding issues of liability. In the court system, the reasonable person theory is applied to the following question: In the same circumstances, how would an average person have behaved?
This theoretical person, neither too cautious nor too fearless, provides an impartial standard against which the conduct of others is judged. The reasonable person standard, however, cannot be applied uniformly to all people. There are differing standards of conduct expected based upon a variety of characteristics that an individual might have.
In judging conduct, reasonable person law considers perceptions, experience and knowledge. For example, a person cannot deny knowledge of commonly known facts such as ice being slippery or alcohol impairing driving ability. The conduct of people engaged in activities requiring special skills, experience or training, such as doctors or airplane pilots, is measured against the standards of reasonably skilled members of the same group.
Individual physical characteristics are another factor taken into consideration. A person who is physically impaired is not expected to meet a standard of conduct impossible for him or her. Mental capacity, however, is ignored as a standard. Someone lacking in emotional stability, judgment or intelligence is not excused from failure to act as a reasonable person. Only one, single objective standard of reasonable behavior exists in the law, and it is not mitigated by considerations of either mental health or mental ability.
Certain external factors, though, are relevant in determining reasonableness, because they might affect how a person acts. For example, the pressing conditions of an emergency might cause reasonable people to make mistakes. Available resources also are taken into consideration. If needed resources are scarce, some actions might be reasonable that would be unreasonable otherwise.
Children are not held to the same standards as adults. Unlike adults, subjective factors such as age, intelligence and experience are taken into account. Generally, children under the age of 7 are exempt from criminal or civil liability for negligence.