Proficient performance of a conjunctive, recursive task by an African gray parrot (Psittacus erithacus).

Abstract

The comprehension skills of an African gray parrot (Psittacus erithacus), Alex, were tested on a taks that included a conjunctive condition. For each trial, Alex was shown different collections of 7 items, each collection chosen from among 100 objects of various combinations of shapes, colors, and materials, and he was asked to provide (vocally) information about the specific instance of one category of an item that was uniquely defined by the conjunction of two other categories (e.g., "What color is the [object defined by shape and material]?"). Other objects exemplified one, but not both, of these defining categories. Alex responded with an accuracy of 76.5%, which indicated that he understood all the elements in the question, including the conjunctive condition, and that he used these elements to guide his search for the one object in the collection that provided the requested information.

A comparative study of human and parrot phonation: Acoustic and articulatory correlates of vowels

“…Specifically, what in the human system is required for speech if a parrot can produce the same sounds without benefit of lips and teeth, and with lungs, nasal cavities, tracheas, bronchi, larynxes, and tongues that differ considerably from those of humans? Is it the parrot's perceptual ability to decode ongoing speech (note Kuhl and Miller, 1978;Pepperberg, 1992), a critical similarity with humans, that enables its production? Might it be such abilities that enable at least the Grey parrot to learn a limited form of human-based semantic communication (e.g., Pepperberg, 1990a) and use the semantic information, like humans (e.g., Pepperberg, 1988; references in Kuhl and Miller, 1978), to further its communicative abilities?…”

Grey parrot number acquisition: The inference of cardinal value from ordinal position on the numeral list

“…The felt-covered tray on which we put stimuli for all trials had been used in earlier studies: label comprehension (Pepperberg, 1990a,b, 1992), object permanence (Pepperberg & Kozak, 1986), other number tasks (Pepperberg, 1994, 2006a,b; Pepperberg & Gordon, 2005). It was concurrently used to train spatial concepts, phoneme recognition (Pepperberg, 2007), and test optical illusions (Pepperberg, Vicinay, & Cavanagh, 2008); it did not cue numerical tasks.…”

“…As whenever he acted thusly (Pepperberg, 1992; Pepperberg & Gordon, 2005; Pepperberg & Lynn, 2000), we ended the session. He received a brief time-out; trials were duly noted and repeated in later sessions.…”

Toward a Cross-Species Measure of General Intelligence

“…5. Sentential: Pepperberg's (1992) African Grey parrot Alex (which died in 2007 at the age of 30) could count two objects ("one, two") and speak in sentences that organized nominal labels and words. When a new question was introduced, "What matter [is this] four corner blue [object made of]?"…”