Versteckte Eigenschaften: Das Gewichtsverständnis des Kea Papageis

Nearly every aspect of our daily lives involves dealing to some extent with the property of weight. For example, we take the weight of objects into account before we lift them, use clues such as size or movement to predict the weight of new objects, and even select objects that are ideally-weighted to solve various problems. It has been proposed that while nonhuman animals can take into account the weight of objects they are directly handling, only humans can reason about weight more abstractly as a constant, unobservable property that exists beyond our direct experience with it. This has significant implications for understanding how animals perceive and reason about their physical environments, however to date we know surprisingly little about other species’ understanding of weight. Thus far, research on this topic remains sparse, typically focusing on tool-using primates, and often on a single aspect of weight understanding. Consequently, we lack a clear picture of how and understanding of weight might reveal itself across different contexts and in different taxa, and the extent to which our own reasoning about weight is unique. The proposed project systematically investigates weight understanding in kea, a highly innovative species of parrot that is not known to use tools in the wild. It presents eight studies that examine this topic across several levels of increasing complexity to address three overarching questions: 1) Can kea attribute weight to objects they are not directly interacting with? 2) What visual or causal cues do kea use to infer the weight of novel objects?3) Can kea use information about weight flexibly to solve different physical problems?The project uses a uniform approach in which each bird is trained to attend to single target weight (light or heavy), and must drop the object of that target weight into a container. Over the course of the studies, the birds are then given varying information (targeting different cognitive abilities) about the weight of different objects, which they can use to select the correct object. This object-choice task structure has been chosen to reduce potentially confounding variables, allowing for clearer interpretation of results, meaningful comparisons of performance between studies and adaptation for comparative work with additional species. Weight is likely to factor into virtually every aspect of problem-solving, including tool use, and yet until now has been surprisingly understudied relative to other aspects of physical cognition. The studies outlined represent the first comprehensive research effort into this topic outside of the primate order, introducing new paradigms that draw on studies of human psychology (e.g., the size-weight illusion) and focusing on a non-tool using species.

FWF Elise-Richter Programm

Messerli Forschungsinstitut für Mensch-Tier-Beziehung
Messerli Forschungsinstitut für Mensch-Tier-Beziehung