Mental retardation (also called mental handicap and, as defined by the UK Mental Health Act 1983, mental impairment and severe mental impairment) is a term for a pattern of persistently slow learning of basic motor and language skills ("milestones") during childhood, and a significantly below-normal global intellectual capacity as an adult. One common criterion for diagnosis of mental retardation is a tested intelligence quotient (IQ) of 70 or below. People with mental retardation are people who are usually described as having developmental disabilities.