Dr. Irene Pepperberg has been studying the intelligence and reasoning abilities of the African Grey parrot for almost 30 years. She has published consistently and extensively in some of the most highly respected scientific journals in her field.

Below is a partial list of her papers that can be downloaded in PDF format, requiring Acrobat Reader for viewing. If you don’t already have Acrobat Reader, you can download it for free by clicking here.

These papers are being provided for private use only, and cannot be published or reprinted without the express permission of the publisher. Quotes from these articles can be used only within the specifications of each publisher. Please consult the individual publishers about their particular guidelines.

This list of papers available for downloading will be expanded as time permits.

We think you’ll enjoy reading the work of Dr. Pepperberg, her work that has demonstrated the amazing intelligence of African Grey parrots to the scientific world.


Pepperberg, I.M., Carey, S. (2012). Grey Parrot Number Acquisition: The Inference of Cardinal Value from Ordinal Position on the Numeral List COGNIT2474

Pepperberg, I.M., Vicinay, J., Cavanagh, P. (2008) The Muller-Lyer illusion is processed by a Grey Parrot (Psittacus erithacus). Perception 37:765-781.

Pepperberg, I.M. (2007a). Grey parrots do not always “parrot”: Phonological awareness and the creation of new labels from existing vocalizations. Language Sciences 29: 1-13.

Pepperberg, I.M. (2006a). Ordinality and inferential abilities of a Grey Parrot (Psittacus erithacus)Journal of Comparative Psychology, 120: 205-216.

Pepperberg, I.M. (2006b). Grey Parrot (Psittacus erithacus) numerical abilities: addition and further experiments on a  zero-like concept. Journal of Comparative Psychology, 120: 1-11.

Pepperberg, I.M., and Gordon, J.D. (2005). Number Comprehension by a Grey Parrot (Psittacus erithacus), Including a Zero-Like ConceptJournal of Comparative. Psychology, 2005, Vol. 119, No. 2, 197-209

Pepperberg, I.M. (2001). Lessons from cognitive ethology: Animal models for ethological computing. Proceedings of the First Conference on Epigenetic Robotics, C. Balkenius, J. Zlatev, H. Kozima, K. Dautenhahn, & C. Breazeal, Eds., Lund University Cognitive Science Series No. 85, Lund, Sweden, (online only)

Pepperberg, I.M., Willner, M.R., and Gravitz, L.B. (1997). Development of Piagetian object permanence in a Grey parrot (Psittacus erithacus). J. Comp. Psych. 111:63-75.

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