Turing Test
Last Updated: July 29, 2026 | By Mihail Sebastian | AI Dictionary
A test of machine intelligence proposed by Alan Turing in 1950: if a human judge chatting by text cannot tell machine from human, the machine passes.
What is the Turing Test?
The Turing test judges machine intelligence by conversation: a human evaluator exchanges text messages with a hidden machine and a hidden person, and if the evaluator cannot reliably tell which is which, the machine passes. Alan Turing proposed it in his 1950 paper “Computing Machinery and Intelligence,” where he called it the imitation game.
Turing’s move was to replace an unanswerable question, “can machines think?”, with an observable one: can a machine’s conversation pass for a person’s?
How the Turing Test Works
The evaluator sits at a terminal connected to two unseen participants, one human and one machine, and may ask anything: opinions, arithmetic, childhood memories, poetry. Text-only exchange strips away voice and appearance, so only the conversation counts.
The machine’s goal is to be indistinguishable, not to be right. Turing’s own example dialogue has the machine pause thirty seconds over an arithmetic problem and answer it wrongly, because instant, perfect calculation would give the game away.
The test measures whether a machine can imitate a person, not whether it understands anything. Large language models now converse fluently enough to fool casual judges, which makes that limit hard to ignore: a chatbot can produce human-sounding text while confidently hallucinating facts.
Example of the Turing Test
An evaluator opens two chat windows. She asks both to describe the smell of rain, then to divide 355 by 113, then what they had for breakfast. Window A answers the division instantly to ten decimal places; window B hesitates, offers “about 3.14,” and jokes about skipping breakfast.
A machine that answers instantly and exactly betrays itself, so a machine built to pass must imitate human texture: hesitation, approximation, small talk. Run the game many times, and if the evaluator’s guesses are no better than chance, the machine has passed.
Related AI terms: Chatbot · Conversational AI · Weak AI · Expert System · Artificial Intelligence
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Mihail Sebastian — Writes about AI governance, regulation, and the technology behind them. Placeholder bio — replace with a real credential line. About