People looking for precursors to artificial intelligence often point to science fiction by authors like Isaac Asimov or thought experiments like the Turing test. But an equally important, if surprising and less appreciated, forerunner is Skinner’s research with pigeons in the middle of the 20th century. Skinner believed that association—learning, through trial and error, to link an action with a punishment or reward—was the building block of every behavior, not just in pigeons but in all living organisms, including human beings. His “behaviorist” theories fell out of favor with psychologists and animal researchers in the 1960s but were taken up by computer scientists who eventually provided the foundation for many of the artificial-intelligence tools from leading firms like Google and OpenAI.
These companies’ programs are increasingly incorporating a kind of machine learning whose core concept—reinforcement—is taken directly from Skinner’s school of psychology and whose main architects, the computer scientists Richard Sutton and Andrew Barto, won the 2024 Turing Award, an honor widely considered to be the Nobel Prize of computer science. Reinforcement learning has helped enable computers to drive cars, solve complex math problems, and defeat grandmasters in games like chess and Go—but it has not done so by emulating the complex workings of the human mind. Rather, it has supercharged the simple associative processes of the pigeon brain.
It’s a “bitter lesson” of 70 years of AI research, Sutton has written: that human intelligence has not worked as a model for machine learning—instead, the lowly principles of associative learning are what power the algorithms that can now simulate or outperform humans on a variety of tasks. If artificial intelligence really is close to throwing off the yoke of its creators, as many people fear, then our computer overlords may be less like ourselves than like “rats with wings”—and planet-size brains. And even if it’s not, the pigeon brain can at least help demystify a technology that many worry (or rejoice) is “becoming human.”
In turn, the recent accomplishments of AI are now prompting some animal researchers to rethink the evolution of natural intelligence. Johan Lind, a biologist at Stockholm University, has written about the “associative learning paradox,” wherein the process is largely dismissed by biologists as too simplistic to produce complex behaviors in animals but celebrated for producing humanlike behaviors in computers. The research suggests not only a greater role for associative learning in the lives of intelligent animals like chimpanzees and crows, but also far greater complexity in the lives of animals we’ve long dismissed as simple-minded, like the ordinary Columba livia.
When Sutton began working in AI, he felt as if he had a “secret weapon,” he told me: He had studied psychology as an undergrad. “I was mining the psychological literature for animals,” he says.
Skinner started his missile research with crows but switched to pigeons when the brainy black birds proved intractable. B.F. SKINNER FOUNDATION
Ivan Pavlov began to uncover the mechanics of associative learning at the end of the 19th century in his famous experiments on “classical conditioning,” which showed that dogs would salivate at a neutral stimulus—like a bell or flashing light—if it was paired predictably with the presentation of food. In the middle of the 20th century, Skinner took Pavlov’s principles of conditioning and extended them from an animal’s involuntary reflexes to its overall behavior.