Artificial intelligence (AI) is the simulation of human intelligence processes by machines, especially computer systems. Specific applications of AI include expert systems, natural language processing, speech recognition and machine vision. AI works by ingesting large amounts of labeled training data to analyze patterns and correlations and use these to make predictions. New AI techniques can generate realistic text, images, music and other media. The four main types of AI are reactive machines, those with limited memory, theory of mind, and self-awareness. AI is incorporated into automation, machine learning, machine vision, natural language processing, robotics, self-driving cars, and text, image and audio generation.