title: More than one way to see it: Individual heuristics in avian visual computation.
abstract: Comparative pattern learning experiments investigate how different species find regularities in sensory input, providing insights into cognitive processing in humans and other animals. Past research has focused either on one species' ability to process pattern classes or different species' performance in recognizing the same pattern, with little attention to individual and species-specific heuristics and decision strategies. We trained and tested two bird species, pigeons (Columba livia) and kea (Nestor notabilis, a parrot species), on visual patterns using touch-screen technology. Patterns were composed of several abstract elements and had varying degrees of structural complexity. We developed a model selection paradigm, based on regular expressions, that allowed us to reconstruct the specific decision strategies and cognitive heuristics adopted by a given individual in our task. Individual birds showed considerable differences in the number, type and heterogeneity of heuristic strategies adopted. Birds' choices also exhibited consistent species-level differences. Kea adopted effective heuristic strategies, based on matching learned bigrams to stimulus edges. Individual pigeons, in contrast, adopted an idiosyncratic mix of strategies that included local transition probabilities and global string similarity. Although performance was above chance and quite high for kea, no individual of either species provided clear evidence of learning exactly the rule used to generate the training stimuli. Our results show that similar behavioral outcomes can be achieved using dramatically different strategies and highlight the dangers of combining multiple individuals in a group analysis. These findings, and our general approach, have implications for the design of future pattern learning experiments, and the interpretation of comparative cognition research more generally.
authors.affiliation: Department of Cognitive Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Language Evolution and Computation Research Unit, University of Edinburgh, EH8 9AD Edinburgh, UK. Electronic address: andrea.ravignani@gmail.com.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ravignani
authors.affiliation: Department of Cognitive Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Gesche
authors.initials: G
authors.lastname: Westphal-Fitch
authors.affiliation: Department of Cognitive Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Aust
authors.affiliation: Department of Cognitive Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Haidlhof Research Station, University of Vienna/University of Veterinary Medicine Vienna/Messerli Research Institute, 2540 Bad Vöslau, Austria.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Schlumpp
authors.affiliation: Department of Cognitive Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Haidlhof Research Station, University of Vienna/University of Veterinary Medicine Vienna/Messerli Research Institute, 2540 Bad Vöslau, Austria. Electronic address: tecumseh.fitch@univie.ac.at.
authors.forename: W Tecumseh
authors.initials: WT
authors.lastname: Fitch
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D010856:Columbidae; D004193:Discrimination Learning / Q000502:physiology*; D000066506:Heuristics; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011563:Psittaciformes; D011930:Reaction Time / Q000502:physiology; D013045:Species Specificity; D014796:Visual Perception / Q000502:physiology*
keywords: Artificial grammar learning; Language evolution; Local/global processing; Maximum likelihood; Model selection; Species differences