Acting as a reasonable person.

Ordinarily, the standard of care owed to a plaintiff under tort law is “acting in a manner a reasonably prudent person would use in the same situation.”
Children (18 and under): the law evaluates on a reduced level and considers a child of the same age and intellect.
Children (18 and under) in adult activities: are generally held to the same standard as an adult.
Mentally ill or incompetent: held to the same standard as a normal adult, the law generally does not give any special considerations.
Physical disabilities: the law evaluates on a reduced level and considers a person with a similar physical disability.