system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do the mental processes of people with Down Syndrome differ from people without it?

(serious)
gpt
People process their environment using their I.Q. and their emotional intelligence. Language skills are particularly important. If someoneone doesn't have a word for something, they can neither process nor remember it. (This is why you cannot recall your infancy. You did not yet have an active vocabulary to categorize and process the things you were seeing and experiencing.)
Typically, a person with Down Syndrome has an I.Q. aproximating that of a child 8 years of age or younger. This means that they also have the vocabulary and reasoning ability of a very young child. Also, much like young children, Down Syndrome people may not have a clear division between the two hemispheres of the brain (as a normal adult does). This inhibits their ability to distinguish between fantasy an reality, between the truth and a lie. The creative side of their brain and the logic center do not correctly categorize information. Also, the transference of learned information from the short term memory to long term memory is compromised in Down Syndrome people. This is why they have difficulty learning new information and skills, and may not recall things like family vacations or certain birthdays unless something unusual happened that would act as a "place marker" to assist in categorizing the memory.