The purpose of artificial intelligence research is to extend human intelligence by exploring the essence of intelligence - to prompt intelligent subjects to hear (speech recognition, machine translation, etc.), see (image recognition, text recognition, etc.), speak (speech synthesis, human-computer dialogue, etc.), think (human-computer games, expert systems, etc.), learn (knowledge representation, machine learning, etc.), and act (robots, self-driving cars, etc.). A system’s ability to correctly interpret external data, to learn from such data, and to use those learnings to achieve specific goals and tasks through flexible adaptation.