Accomplishments
Pepperberg was modest in her descriptions of Alex's accomplishments, not claiming that he could use "language" but instead saying that he used a two-way communications code. Listing Alex's accomplishments in 1999, Pepperberg said he could identify 50 different objects and recognize quantities up to six; that he could distinguish seven colors and five shapes, and understand the concepts of "bigger", "smaller", "same", and "different", and that he was learning "over" and "under". Alex passed increasingly more difficult tests measuring whether humans have achieved Piaget's Substage 6 object permanence. Alex showed surprise and anger when confronted with a nonexistent object or one different from what he had been led to believe was hidden during the tests.
Alex had a vocabulary of about 150 words, but was exceptional in that he appeared to have understanding of what he said. For example, when Alex was shown an object and was asked about its shape, color, or material, he could label it correctly. He could understand that a key was a key no matter what its size or color, and could figure out how the key was different from others. He asked what color he was, and learned "grey" after being told the answer six times.
Alex understood the turn-taking of communication and often the syntax used in language. He called an apple a "banerry", which Pepperberg thought to be a combination of "banana" and "cherry", two fruits he was more familiar with.
Alex could even add, to a limited extent, correctly giving the number of like objects on a tray. Pepperberg said that if he could not count, the data could be interpreted as his being able to quickly and accurately estimate the number of something, better than humans can. When he was tired of being tested, he would say “Wanna go back,” meaning he wanted to go back to his cage, and in general, he would request where he wanted to be taken by saying "Wanna go...", protest if he was taken to a different place, and sit quietly when taken to his preferred spot. He was not trained to say where he wanted to go, but picked it up from being asked where he'd like to be taken. If the researcher displayed irritation, Alex tried to defuse it with the phrase, “I’m sorry.” If he said “Wanna banana,” but was offered a nut instead, he stared in silence, asked for the banana again, or took the nut and threw it at the researcher or otherwise displayed annoyance, before requesting the item again. When asked questions in the context of research testing, he gave the correct answer approximately 80% of the time.
Once, Alex was given several different colored blocks (two red, three blue, and four green—similar to the picture above). Pepperberg asked him, "What color three?" expecting him to say blue. However, as Alex had been asked this question before, he seemed to have become bored. He answered "five!" This kept occurring until Pepperberg said "Fine, what color five?" Alex replied "none". This suggests that parrots, like children, get bored. Sometimes, Alex purposely answered the questions incorrectly, despite knowing the correct answer.
Preliminary research also seems to indicate that Alex could carry over the concept of four blue balls of wool on a tray to four notes from a piano. Pepperberg was also training him to recognize "4" as "four". Alex also showed some comprehension of personal pronouns; he used different language when referring to himself or others, indicating a concept of "I" and "you".
In July 2005, Pepperberg reported that Alex understood the concept of zero. If asked the difference between two objects, he also answered that; but if there was no difference between the objects, he said “none", which meant that he understood the concept of nothing or zero. In July 2006, Pepperberg discovered that Alex's perception of optical illusions was similar to human perception.
Pepperberg was training Alex to recognize English phonemes, in the hope that he would conceptually relate an English written word with the spoken word. He could identify sounds made by two-letter combinations such as SH and OR.
Read more about this topic: Alex (parrot)