Choosing and Using Tools: Capuchins (Cebus apella) Use a Different Metric Than Tamarins (Saguinus oedipus)
Cotton-top tamarins (Saguinus oedipus) selected canes positioned so that a straight inward pull brought food within reach (M. D. Hauser, 1997; see also record 1997-41347-003). Tamarins failed to retrieve food with canes in other positions, and they did not reposition these canes. In this study, tufted capuchin monkeys (Cebus apella) preferred canes they could pull […]
Grey parrot (Psittacus erithacus) numerical abilities: Addition and further experiments on a zero-like concept
A Grey parrot (Psittacus erithacus), able to quantify 6 or fewer item sets (including heterogeneous subsets) by using English labels (I. M. Pepperberg, 1994), was tested on addition of quantities involving 0-6. He was, without explicit training, asked, “How many total X?” for 2 sequentially presented collections (e.g., of variously sized jelly beans or nuts) […]
Ordinality and inferential abilities of a grey parrot (Psittacus erithacus)
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 […]