title: Ordinality and inferential abilities of a grey parrot (Psittacus erithacus).
abstract: A grey parrot (Psittacus erithacus), able to label the color of the bigger or smaller object in a pair (I. M. Pepperberg & M. V. Brezinsky, 1991), to vocally quantify < or =6 item sets (including heterogeneous subsets; I. M. Pepperberg, 1994), and separately trained to identify Arabic numerals 1-6 with the same vocal English labels but not to associate Arabic numbers with their relevant physical quantities, was shown pairs of Arabic numbers or an Arabic numeral and a set of objects and was asked for the color of the bigger or smaller one. The parrot's success showed he (a) understood number symbols as abstract representations of real-world collections, (b) inferred the relationship between the Arabic number and the quantity via stimulus equivalence, and (c) understood the ordinal relationship of his numbers.
authors.affiliation: Department of Psychology, Brandeis University, Waltham, MA 02454, USA. impepper@media.mit.edu
authors.forename: Irene M
authors.initials: IM
authors.lastname: Pepperberg
mesh_terms: D000818:Animals; D001245:Association Learning; D003118:Color Perception; D032882:Comprehension; D003210:Concept Formation; D004193:Discrimination Learning; D008433:Mathematics; D010311:Parrots; D010364:Pattern Recognition, Visual; D011340:Problem Solving; D011601:Psychophysics; D012858:Size Perception; D013561:Symbolism; D014828:Vocalization, Animal