title: Reasoning by exclusion in the kea (Nestor notabilis).
abstract: Reasoning by exclusion, i.e. the ability to understand that if there are only two possibilities and if it is not A, it must be B, has been a topic of great interest in recent comparative cognition research. Many studies have investigated this ability, employing different methods, but rarely exploring concurrent decision processes underlying choice behaviour of non-human animals encountering inconsistent or incomplete information. Here, we employed a novel training and test method in order to perform an in-depth analysis of the underlying processes. Importantly, to discourage the explorative behaviour of the kea, a highly neophilic species, the training included a large amount of novel, unrewarded stimuli. The subsequent test consisted of 30 sessions with different sequences of four test trials. In these test trials, we confronted the kea with novel stimuli that were paired with either the rewarded or unrewarded training stimuli or with the novel stimuli of previous test trials. Once habituated to novelty, eight out of fourteen kea tested responded to novel stimuli by inferring their contingency via logical exclusion of the alternative. One individual inferred predominantly in this way, while other response strategies, such as one trial learning, stimulus preferences and avoiding the negative stimulus also guided the responses of the remaining individuals. Interestingly, the difficulty of the task had no influence on the test performance. We discuss the implications of these findings for the current hypotheses about the emergence of inferential reasoning in some avian species, considering causal links to brain size, feeding ecology and social complexity.
authors.affiliation: Department of Cognitive Biology, University of Vienna, Vienna, Austria. mark.ohara@univie.ac.at.|Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria. mark.ohara@univie.ac.at.
authors.forename: Mark
authors.initials: M
authors.lastname: O'Hara
authors.affiliation: Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria.
authors.forename: Raoul
authors.initials: R
authors.lastname: Schwing
authors.affiliation: Department of Cognitive Biology, University of Vienna, Vienna, Austria.
authors.forename: Ira
authors.initials: I
authors.lastname: Federspiel
authors.affiliation: Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria.
authors.forename: Gyula K
authors.initials: GK
authors.lastname: Gajdon
authors.affiliation: Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Huber
mesh_terms: D000818:Animals; D002755:Choice Behavior; D003071:Cognition; D007858:Learning; D010311:Parrots; D012201:Reward
keywords: Avian cognition; Categorisation; Inference by exclusion; Kea (Nestor notabilis); Touch screen