How Smart Are African Gray Parrots? What Alex Taught Us

What did Alex the parrot learn?

Most of what we know comes from one bird: Alex, an African gray parrot bought from a pet shop in 1977 by the American scientist Irene Pepperberg. Over 30 years, at Purdue University, the University of Arizona, MIT, Harvard and Brandeis, she trained and tested him until his death in September 2007. His name was short for “avian learning experiment”.

By the late 1990s, Alex could:

• name about 50 different objects, such as keys, corks, paper and wood;
• identify seven colors and five shapes;
• say how many items were on a tray, up to six;
• answer “What’s same?” and “What’s different?” about two objects, replying with “color”, “shape” or “matter”;
• tell which of two objects was bigger or smaller.

Alex used more than 100 English words in total. What impressed scientists most was that he could apply these words to new objects. Shown a key of a size and color he had never seen, he still called it a key and could name its color.

How did Pepperberg teach Alex?

Earlier attempts to teach parrots had largely failed. Pepperberg used a method called the model/rival technique. Two humans would act out the lesson in front of the parrot: one asked a question about an object, and the other answered. A correct answer earned the object itself, and a wrong answer meant the object was taken away. The humans then swapped roles.

This approach made the link between word and object clear and gave the bird a reason to pay attention. Alex was rewarded with the item he had named rather than with food, so the word “cork” brought him a cork. Over time he began to use words to ask for things and places, such as “wanna go back” when he was tired of a session.

Alex’s most famous moments

Several moments made Alex well known far beyond science.

The first question. Looking at himself in a mirror, Alex asked what color he was. He learned the word “gray” after being told six times. He is often described as the first non-human animal known to have asked a question.

A zero-like concept. In tests where he was asked which color group had a certain number of items, Alex sometimes answered “none” when no group matched. Pepperberg described this as a concept similar to zero.

Inventing words. Alex called an apple “banerry”, which seemed to combine “banana” and “cherry”, two fruits he already knew.

When he died at about 31, Pepperberg reported that his last words to her the evening before were “You be good. See you tomorrow. I love you”, a phrase he said every night.

What have later studies shown?

Research on gray parrots continued after Alex. Pepperberg went on to work with other gray parrots, especially one named Griffin. In a 2020 study, Griffin did about as well as Harvard undergraduates, and better than young children, on a demanding memory version of the “shell game”, in which the player has to track items hidden under moving cups.

Other researchers have tested untrained gray parrots too:

• Reasoning by exclusion. Gray parrots in Vienna learned to find food hidden under one of two cups after being shown that the other cup was empty, a simple form of logical inference.
• Reasoning from sound. In a later study, gray parrots chose the right cup after hearing it shaken, using sound alone to work out where food was.
• Self-control. Griffin was able to wait for a better reward instead of taking a less preferred food at once, an ability linked to planning.
• Helping others. In a 2020 study by researchers at the Max Planck Institute for Ornithology, gray parrots passed tokens through a hole to a neighbor so that the neighbor could trade them for food, even when they got nothing themselves. Blue-headed macaws tested the same way did not.

Why are gray parrots so clever?

Birds once had a reputation for being “bird-brained”, but research has overturned this. Parrots and crows have relatively large brains for their body size, and their forebrains are packed with very large numbers of neurons, more tightly than in mammals of similar brain size. This dense wiring may help explain why some birds rival apes in certain problem-solving tasks.

Life in the wild also rewards intelligence. Gray parrots live for decades, travel long distances to find fruiting trees, live in large social groups and must learn which foods are safe. They learn calls from their flock and can imitate a wide range of sounds. A social, long-lived animal that must remember places, relationships and food sources has good reasons to evolve a flexible mind. Gray parrots appear among the smartest animals for this reason, alongside corvids, apes and dolphins; see also how smart crows are.

Do gray parrots really understand language?

Not all scientists accept that Alex used language. Critics, including the psychologist Herbert Terrace, argued that his answers might be well-trained responses to cues, similar to the famous horse Clever Hans, who seemed to count but was reading his owner’s body language. Pepperberg herself never claimed that Alex had human language; she described it as a two-way communication code.

Supporters point out that Alex answered correctly about 80% of the time when tested, often with strangers asking the questions, and that he could label new objects he had never been trained on. The safest conclusion is that gray parrots can link words to meanings far better than most people expected, without matching the grammar and creativity of human speech. For other species that can copy human words, see which birds can talk.