What is AI? Artificial intelligence, or AI, is machines and computer programs that can imitate smart human behavior, such as making predictions and decisions. AI helps phones understand the words that people say out loud. A computer can be programmed with exact steps, the way a baker follows a recipe. It can also be set up to learn from data. Some tasks are easy for a person but hard to explain to a computer, such as telling pictures of different people apart. Even so, an AI program does not think the way a person does.
In 1950 the mathematician Alan Turing published a paper that asked, "Can machines think?" In the game he described, a person asking questions tries to tell which of two hidden players is the machine. The other is the person. The answers are typed. The name "artificial intelligence" comes from a 1955 proposal for a summer project at Dartmouth College in New Hampshire. That proposal guessed that every part of learning could be described so exactly that a machine could be made to simulate it. The field of AI is said to have started officially in 1956, at a summer conference at Dartmouth.
In May 1997 a chess computer called Deep Blue beat the world chess champion in a six-game match, 3½ to 2½. It was the first time a computer beat a reigning world chess champion in a match under tournament conditions. Some game-playing programs work by brute force: they try a huge number of possible moves and replies. Deep Blue could examine about 200 million chess moves each second. In March 2016 a Go-playing program called AlphaGo beat a top Go player four games to one. Before AlphaGo, many people thought it would be about a decade before computers could challenge skilled Go players. AlphaGo fine-tuned itself by playing games against slightly changed copies of itself.
How does AI learn? Many AI programs learn by looking at lots of examples, such as pictures that people have labeled as dogs. The information that an AI program learns from is called training data. A program usually needs a very large amount of it to work well. Machine learning is one way to make AI: the computer finds patterns in data. A computer program can learn to tell cards marked on the left from cards marked on the right. In 1958 a room-sized computer taught itself this after 50 tries.
A neural network is a kind of AI program made of many simple parts, called nodes, joined together. It is modeled loosely on the human brain. Most of today's neural networks are organized into layers of nodes. When a neural network is trained, the numbers that set how strongly its parts connect are adjusted until it gives the right answers for the training examples. In supervised learning, a program is trained on examples that people have already labeled. Even after an AI program is trained, it can be hard to find out why it gave a certain answer.
A large language model is the kind of AI behind many chatbots. It is trained on text from sources across the internet, such as books and web forum discussions. It works by predicting which word is likely to come next. It breaks what you type into small pieces called tokens. Because a language AI picks words by probability, it can produce a false statement that sounds right. AI chatbots can make up facts and even make up the sources they name.
If the examples an AI learns from leave some people out, the AI can work worse for those people. AI can be used to make decisions that affect people, such as whether a person is admitted to a school or approved for a loan. A spam filter is a program that sorts junk email from email you want. It can wrongly flag a good email as spam, which is called a false positive. A chatbot may also not know about very recent events. It can only use the information it learned from.
AI can make mistakes and can say things that are not true. It can be wrong even when it sounds sure, so a confident answer is not proof. People should check what an AI tells them before they trust it. A good way to check is to open a new tab and look the facts up on other reliable pages, which is called lateral reading. If a chatbot names a book or article, a person should search to confirm that it really exists. An AI should not be asked to check its own work: a person should look for outside sources.
Words to know
- tokens: small word pieces
- nodes: simple parts
- simulate: act like
- lateral: sideways checking
- brute: try everything
