Cognition in an African gray parrot (Psittacus erithacus): Further evidence for comprehension of categories and labels.

Abstract

This experiment was designed to examine further the comprehension skills of an African gray parrot (Psittacus erithacus). For each test trial the parrot was shown a different collection of 7 physical exemplars (each collection chosen from among 100 objects of various combinations of shapes, colors, and materials); was asked 1 of 4 possible vocal questions, each of which requested a different type of information (e.g., «What color is [designated object]?») about a single object in the collection; and was required to reply vocally to each question