Analogical reasoning in keas, ravens and pigeons
One of the most controversially debated topics about animal pre-linguistic abilities is the ability of analogical reasoning (reasoning based on the inference that if two or more things agree with one another in some respects it is likely that they will agree in others). Until now, only language-trained animals have unequivocally shown this ability. In our lab, some dogs and all human participants successfully inferred class membership by exclusion, but pigeons failed. However, the failure of evidence is not the evidence of its failure, thus further experiments are necessary to determine the underlying mechanisms and their taxonomic distribution.
Among birds, corvids and parrots are prime candidates for advanced cognitive abilities. For comparative avian cognition, these two groups are particularly interesting as their cognitive abilities are most likely the result of convergent evolution. Still, hardly anything is known about cognitive similarities and dissimilarities between corvids and parrots. As inconsistent methodology might have contributed to the revealed inter-species differences in previous studies, this PhD project will examine reasoning by exclusion in pigeons, keas and ravens under almost equal experimental conditions. Keas and ravens are added to pigeons, as they are the most promising candidates among corvids and parrots that are available in our lab at Haidlhof. Of course, it would also be interesting to test New Caledonian crows and grey parrots, but this will depend on their availability (actually, we have already started to test NC crows in Bavaria and grey parrots in the Zoo Schönbrunn).
We will start by using the new inference by exclusion paradigm developed in our lab. Another test for inference by exclusion reasoning abilities in non-linguistic species is to infer the location of hidden food based on information about its absence in another location. In a recent study, we tested ravens and keas in a choice task requiring the search for food in two differently shaped tubes. Keas were more successful and chose the baited tube more often than ravens. On the other hand, ravens applied the more efficient strategies, using inference by exclusion more frequently than keas. However, none of them demonstrated an understanding for the impact of the tubes’ shapes. An additional experiment confirmed that ravens and keas either do not possess the same reasoning skills or may apply them differently. To disentangle the possibly different cognitive mechanisms and species-specific behavioral dispositions, further comparison studies will be necessary. If possible, the range of species will be extended to New Caledonian crows and grey parrots, and to pigeons as control group.