The difference between "intellectual disability" and "developmental disability"

By now, many of you know that "intellectual disability" (ID) is the new term for a low IQ—what we used to call "mental retardation". In recent times, many people use "intellectual disability" as an umbrella term for any deficit in a person's thought processes. However, this term is actually a diagnostic label for a certain type of developmental disability that slows down learning and logical thought processes. We need another label for those who excel intellectually but struggle with other skills such as social interaction.

The abbreviation "I/DD" is widely understood to stand for "intellectual and developmental disabilities". However, on websites and discussion forums a common example of a "developmental disability" that is not an "intellectual disability" is a physical disability such as being paraplegic. This contributes to a popular perception that autism is a form of intellectual disability. In fact, autism is another diagnostic label for a different set of mental deficits from the ones seen in intellectual disability. An "intellectually disabled" person's limitations stem primarily from deficits in the ability to learn concepts, such as reading, writing, arithmetic, and reasoning, whereas an autistic person's limitations are primarily due to problems recognizing social cues or processing language.

Many people have a perception that autism is a form of intellectual disability. This may be because, in practice, what limits the ability of people with ID to function in daily life are struggles with forms of communication or social activities that require problem-solving abilities that the rest of us take for granted; they often are unable to speak in full sentences or understand more complex social rules. Many autistic people are limited in similar ways, and so daily interactions between neurotypical people, autistic people, and those with ID have many of the same challenges. Statistically, a majority of autistic people do, indeed, have a below-average IQ, though it often is not low enough for them to be considered "intellectually disabled". However, many autistic individuals have an average, or even (as in my case) an above-average IQ. These individuals think quite logically and learn skills such as artistic or even mathematical abilities very quickly, but are delayed in developing language (even to the point of being completely nonverbal) or understanding social cues because the parts of the brain that are involved in those specific areas of functioning develop more slowly than typical. To truly understand the disabilities of people like me requires understanding the difference between the ability to learn concepts and the ability to communicate.

So, the "I/DD" community is not just a mix of intellectually disabled people with people in wheelchairs. It includes people who are quite intelligent and able-bodied but have deficits in other areas of adaptive functioning, such as communication and focus. If society wants to include people with I/DD, it needs to learn not just about the needs and limitations that can be seen at first glance, but the specific areas of help that people need to put the gifts that they have to practical use in solving humanity's problems.