Basic simple cognitive tasks. Keep in mind that isn't an official medical definition, just my own. It's like awareness in the moment, among other things.

One example might be like, not asking certain questions, like asking a woman how much she weighs or a trans person about their genitals. Another example might just be basic tasks like driving without blocking traffic. Another example might be, not being a creep to a girl that you like. (Not following her around and falling in love when she doesn't even know you) Another example might be not looking at the sun and not realizing the black spots in your eyes are actually damage. Another example, thinking it's okay to take medicine when you are pregnant that isn't absolutely necesarey and also advised by a doctor. Another example might be not eating around people with bad hygiene. So many countless examples. It in some contexts refers to your ability to think through simple situations where the answer should be obvious, but can also just refer to your awareness of simple and obvious things.

Once again this isn't a medical definition, I know people on the internet get confused a great deal these days, but this is just my own definition.

Schizophrenics lack this sense to a large extent, because many diagnosed schizophrenics couldn't think their way out of a paper bag, autistic people lack it to varying degrees for different reasons, usually not a degenerated brain. Autism can refer to many different things from lack of mental function to just very abnormal mental function, which isn't always necessarily a negative if they can function well in life. Autism is only really an issue when it makes people have a hard time functioning like a normal human being, (getting a job, making friends, finding loving relationships, taking care of themselves, etc) many autistic people are extremely intelligent in certain fields that they like. They often have an incredible ability to focus beyond normal humans. Schizophrenia is much different. A schizophrenic probably cannot focus on anything. Their minds are full of intrusive and paranoid thoughts and they often cannot easily distinguish reality from their thoughts.