How do you distinguish a human responds from an AI/computer responds?

Question

How do you distinguish a human responds from an AI/computer responds?

Answer 1

The Turing Test.  Proposed by Alan Turing in the 50's, it's used to measure a machine's level of intelligence, or rather, its ability to imitate human intelligence.

Basically, an impartial judge reads a Q&A session between the AI and the Human.  Supposedly, if the machine passes the session, it is said to be of human intelligence.

Then again, if the human doesn't pass, what does it say?

Also, one of the greatest ways to measure intelligence is to determine sentience, or the ability to be self-aware.  Computers are not self aware, humans are.

There's also the ability to distinguish between different meanings of the same word.  For example, the word "dog" could be refering to an animal, a worthless or contemptible person, or even to the word itself.  A human would be able to tell the difference based on context, a computer would not.

Answer 2

A computer's response is more likely to be spelled correctly and have no grammatical answers.