Intellectual disability (ID) was once referred to as mental retardation. However, the term 'mental retardation' is still used very popularly. It is characterized by slow learning and an inability to perform day-to-day activities. Individuals with mental retardation, have a below average IQ, which is calculated below 70 to 75. Interestingly, the degree of this condition varies from case to case, making each of its victim, unique.