Artificial intelligence is intelligence demonstrated by machines, as opposed to the natural intelligence displayed by humans or animals.
Leading AI textbooks define the field as the study of "intelligent agents": any system that perceives its environment and takes actions that maximize its chance of achieving its goals.
Some popular accounts use the term "artificial intelligence" to describe machines that mimic "cognitive" functions that humans associate with the human mind, such as "learning" and "problem solving", however this definition is rejected by major AI researchers.
AI applications include advanced web search engines, recommendation systems, understanding human speech, self-driving cars, and competing at the highest level in strategic game systems.
As machines become increasingly capable, tasks considered to require "intelligence" are often removed from the definition of AI, a phenomenon known as the AI effect. For instance, optical character recognition is frequently excluded from things considered to be AI, having become a routine technology.