ИСТИНА

Two juvenile Orange-winged amazons (Amazona amazonica) were trained in a two-alternative simultaneous matching-to sample task with stimulus sets of three different categories: color (black versus yellow), shape (Arabic numbers 1 and 2), and number of elements (arrays of one and two items). The training was continued until the criterion (80% correct choices over 96 consecutive trials) had been reached for each of the three sets. The birds needed a total of 1152 and 1876 training trials before the testing began. In the experiment 1, the parrots successfully transferred the matching rule to sets of novel stimuli: blue and red colors, different types of shading, numbers and arrays ranging from 3 to 8. In the experiment 2, the birds proved to be able to match items based on the relationship between the sample and comparison stimuli (same size, first-order relation) at above-chance levels. They made 89 and 97 correct choices, correspondently, over 120 trials. In the experiment 3, both parrots were able to perceive the relationship between items in the sample stimulus pair and match this relation to that between items in the comparison stimulus pair (same size, same shape and same color between items, second-order relation). They made 83 and 93 correct choices over 120 trials (same size), 73 and 72 correct choices over 96 trials (same shape) and 69 and 67 correct choices over 96 trials (same color). This latter finding demonstrates that young amazons are capable of abstracting relations between relations.