He was part of a study under animal psychologist Irene Pepperberg since 1977 at two different universities: Brandeis University in Massachusetts and before that, University of Arizona. He died on Sept 7, 2007, of yet unknown causes. He knew about 100 words as of 2000, and was not ordinary because he appeared to understand 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. If he was asked the difference between two things, he would also answer that, but if there was no difference between the things, he would say “none.”