Irene Pepperberg Has Been Working with an African Grey Parrot

Multiple Choice

Irene Pepperberg has been working with an African grey parrot named Alex. Her research has revealed that

A) Alex is able to make requests and to answer simple questions about objects.
B) Alex's linguistic abilities are limited to the "parroting" of phrases that he has heard Irene speak.
C) Alex shows no evidence of cognitive abilities, because his brain is the size of a walnut.
D) Alex is capable of addition, subtraction, multiplication, and division problems, showing an innate understanding of numbers.