Reactive machines, limited memory, theory of mind, and self-aware AI are the four types of artificial intelligence. The first two are widespread, while the other two are in development.
Reactive machines are most commonly used; they contain no prior knowledge, nor do they store anything in their memory. They, as their name suggests, react to the current state presented to them.
Limited memory AI is now being used in self-driving cars, employing a range of data and machine learning to perform calculations in real-time. Researchers are now trying to reach the point of producing theory of mind machines, which are capable of understanding the intent behind data instead of just processing it.
Self-aware AI is still a science-fiction dream (or nightmare). It requires humans to fully understand what consciousness really is and then replicate it and put it into a machine. This final stage of AI development, if it ever happens, will allow machines to be completely autonomous, synthetic humans – androids, in other words.