And he can recognize quantities up to six. Many pet owners give parrots a few toys and leave them alone for eight or nine hours a day. But like children, they need interaction. He also has learned the concepts of categorization same and different, bigger and smaller, and he is now working on the idea of over and under giant steps in human intellectual development. Therefore, he seems to understand not only the concepts of same and different but also the abstract concept of absence.
Many scientists say that only people can think.
The question is to what extent do other animals think, and to what extent is their thinking similar to ours. But there's certainly enough data from experimental psychological labs to show that these animals can process information. While she was studying for a Ph.D. in theoretical chemistry, which she received from Harvard University in 1976, she got the idea to study parrots. She had seen PBS Nova documentaries on how animals learn and was amazed. The films focused on chimps using sign language, communication with dolphins, and research on singing whales and birds.